| 1. |
- Anderson, Emma S., 1975-, et al.
(författare)
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Developing chicken oligodendrocytes express the type IV oligodendrocyte marker T4-O in situ, but not in vitro
- 2000
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Ingår i: Neuroscience Letters. - 0304-3940 .- 1872-7972. ; 284:1-2, s. 21-24
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Tidskriftsartikel (refereegranskat)abstract
- Accumulating data suggest that the oligodendrocyte population includes morphological and biochemical subtypes. We recently reported that a polyclonal antiserum against an unknown antigen, the T4-O molecule, labels a subpopulation of chicken oligodendrocytes, obviously representing the type IV variety of Del Rio Hortega. The present study examines the developmental expression of the T4-O molecule in situ and in vitro. The results show that T4-O immunoreactive cells first appear at E15 in the ventral funiculus. But, oligodendrocytes cultured in vitro with or without neurones do not develop a T4-O immunoreactivity. We conclude that oligodendrocytes in the spinal cord of chicken embryos first express the T4-O molecule some time after onset of myelination, and that the T4-O immunoreactive phenotype does not develop in vitro.
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| 2. |
- Anderson, Emma S., 1975-, et al.
(författare)
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Molecular heterogeneity of oligodendrocytes in chicken white matter
- 1999
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Ingår i: Glia. - 0894-1491 .- 1098-1136. ; 27:1, s. 15-21
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Tidskriftsartikel (refereegranskat)abstract
- The classical studies by Del Rio Hortega (Mem. Real. Soc. Espan. Hist. Nat. 14:40–122, 1928) suggest that the oligodendrocyte population includes four morphological subtypes. Recent data from the cat and the rat show that the anatomy of oligodendrocytes related to early myelinating prospective large fibers differs from that of oligodendrocytes related to late myelinating prospective small fibers. After application of a polyclonal antiserum to cryostat sections from the chicken CNS, we noted that glial cells in the spinal cord white matter had become labeled. Analysis of the occurrence and cellular localization of this immunoreactivity—the T4-O immunoreactivity—in the CNS of the adult chicken showed that T4-O immunoreactive cells are enriched in the ventral funiculus and superficially in the lateral funiculus of the spinal cord, where they are co-localized with large fibers. Double staining with T4-O antiserum and anti-GFAP or the lectin BSI-B4 revealed that T4-O immunoreactive cells are not astrocytes or microglia. Staining with anti-HSP108, a general marker for avian oligodendrocytes, showed that T4-O immunoreactivity defines an oligodendroglial subpopulation. A search for T4-O immunoreactivity in spinal cord white matter of some other vertebrates revealed that T4-O immunoreactive cells are not present in sections from fish, frog, turtle, rat, and rabbit spinal cord white matter. These results suggest the presence of a fiber size-related molecular heterogeneity among chicken white matter oligodendrocytes.
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| 3. |
- Anderson, Emma S., et al.
(författare)
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Myelination of prospective large fibres in chicken ventral funiculus
- 2000
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Ingår i: Journal of Neurocytology. - 0300-4864 .- 1573-7381. ; 29:10, s. 755-764
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Tidskriftsartikel (refereegranskat)abstract
- In mammals, the oligodendrocyte population includes morphological and molecular varieties. We reported previously that an antiserum against the T4-O molecule labels a subgroup of oligodendrocytes related to large myelinated axons in adult chicken white matter. We also reported that T4-O immunoreactive cells first appear in the developing ventral funiculus (VF) at embryonic day (E)15, subsequently increasing rapidly in number. Relevant fine structural data for comparison are not available in the literature. This prompted the present morphological analysis of developing and mature VF white matter in the chicken. The first axon-oligodendrocyte connections were seen at E10 and formation of compact myelin had started at E12. Between E12 and E15 the first myelinating oligodendrocytes attained a Schwann cell-like morphology. At hatching (E21) 60% of all VF axons were myelinated and in the adult this proportion had increased to 85%. The semilunar or polygonal oligodendrocytes associated with adult myelinated axons contained many organelles indicating a vivid metabolic activity. Domeshaped outbulgings with gap junction-like connections to astrocytic profiles were frequent. Oligodendrocytes surrounded by large myelinated axons and those surrounded by small myelinated axons were cytologically similar. But, thick and thin myelin sheaths had dissimilar periodicities and Marchi-positive myelinoid bodies occurred preferentially in relation to large myelinated axons. We conclude that early oligodendrocytes contact axons and form myelin well before the first expression of T4-O and that emergence of a T4-O immunoreactivity coincides in time with development of a Type IV phenotype. Our data also show that oligodendrocytes associated with thick axons are cytologically similar to cells related to thin axons. In addition, the development of chicken VF white matter was found to be similar to the development of mammalian white matter, except for the rapid time course.
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| 4. |
- Edoff, Karin, 1973-, et al.
(författare)
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Neuropeptide effects on rat chondrocytes and perichondrial cells in vitro
- 2003
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Ingår i: Neuropeptides. - : Elsevier BV. - 0143-4179 .- 1532-2785. ; 37:5, s. 316-318
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Tidskriftsartikel (refereegranskat)abstract
- This study examines if cultured chondrocytes and perichondrial cells change the level of cAMP and/or cGMP in response to application of the neuropeptide calcitonin gene-related peptide (CGRP). Cells collected from the knee region of 4–8 days old rat pups were cultured in vitro. Cultures were exposed to 10−10–10−6 M CGRP during 10 minutes. The levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) in the cultures and in controls were determined by radioimmunoassay. The results show that application of CGRP causes a distinctly increased level of cAMP, that was absent when CGRP was applied together with the CGRP1 receptor antagonist. The level of cGMP was not obviously altered. Hence, it is possible that terminals of primary sensory neurones present in developing cartilage influence chondrocytes and perichondrial cells via local release of CGRP.
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| 5. |
- Edoff, Karin, 1973-, et al.
(författare)
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Retrograde tracing and neuropeptide immunohistochemistry of sensory neurones projecting to the cartilaginous distal femoral epiphysis of young rats
- 2000
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Ingår i: Cell and Tissue Research. - : Springer Science and Business Media LLC. - 0302-766X .- 1432-0878. ; 299:2, s. 193-200
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Tidskriftsartikel (refereegranskat)abstract
- Although cartilage is considered to be devoid of innervation, axons occur in the perichondrium and during development in cartilage canals, thereby having a relatively close spatial relationship to chondroblasts and chondrocytes. The present study locates the source of the sensory innervation of the femoral cartilaginous epiphyses of young rats and investigates whether the neuropeptide calcitonin gene-related peptide (CGRP) can influence chondrocytes. Retrograde tracing from the distal femoral epiphysis of young rats with Fast Blue (FB) showed labelled neuronal profiles in the L2-L5 dorsal root ganglia. Sample countings indicated that 50% of the FB-labelled neuronal profiles were located at the L3 level and 25% at the L4 level. The labelled neurones had diameters of 15-40 µm, with a peak at 25-30 µm. Immunohistochemistry showed that about 50% of the FB-labelled profiles contained CGRP. Together with the finding that CGRP influences bone cells to generate the second messenger cAMP, this result suggested the hypothesis that chondrocytes might be similarly influenced by CGRP. However, stimulation of cartilage slices with CGRP in vitro followed by an assay of the cAMP content did not provide support for this hypothesis. We conclude that primary sensory neurones containing CGRP project to the perichondrium and to cartilage canals of growing cartilage, and that exogenous CGRP does not elevate the cAMP content of cartilage slices in vitro.
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| 6. |
- Edoff, Karin, et al.
(författare)
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The developmental skeletal growth in the rat foot is reduced after denervation
- 1997
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Ingår i: Anatomy and Embryology. - : Springer Science and Business Media LLC. - 0340-2061 .- 1432-0568. ; 195:6, s. 531-538
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Tidskriftsartikel (refereegranskat)abstract
- It has long been known that bone is innervated. In recent years it has been suggested that the local nerves may influence the growth and metabolism of bone by way of neuropeptides. The transient local presence of nerve-containing cartilage canals just before formation of secondary ossification centres in rat knee epiphyses seems to support that view. The purpose of the present study was to see if denervation affects the developmental growth of metatarsal bones in the rat hindfoot. We made sciatic and femoral neurectomies in 7- day-old rat pups and examined the hindfeet at various times after surgery. Immunohistochemical analysis showed that denervation was complete. Radiographic examination revealed that the metatarsal bones were significantly shorter in denervated hindfeet 30 days after denervation (average relative shortening 9.9±2.3%). Measurements of total foot length showed that denervated feet were subnormally sized already five days postoperatively, before the onset of secondary ossification. The timing of the latter was not affected by denervation. Control rats subjected to tenotomies exhibited normal metatarsal bone lengths. On the basis of these results we suggest that the local nerves may influence the growth of immature bones but do not affect secondary ossification.
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| 7. |
- Fried, K., et al.
(författare)
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Molecular signaling and pulpal nerve development
- 2000
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Ingår i: Critical Reviews in Oral Biology and Medicine. - : SAGE Publications. - 1045-4411 .- 1544-1113. ; 11:3, s. 318-332
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this review is to discuss molecular factors influencing nerve growth to teeth. The establishment of a sensory pulpal innervation occurs concurrently with tooth development. Epithelial/mesenchymal interactions initiate the tooth primordium and change it into a complex organ. The initial events seem to be controlled by the epithelium, and subsequently, the mesenchyme acquires odontogenic properties. As yet, no single initiating epithelial or mesenchymal factor has been identified. Axons reach the jaws before tooth formation and form terminals near odontogenic sites. In some species, local axons have an initiating function in odontogenesis, but it is not known if this is also the case with mammals. In diphyodont mammals, the primary dentition is replaced by a permanent dentition, which involves a profound remodeling of terminal pulpal axons. The molecular signals underlying this remodeling remain unknown. Due to the senescent deterioration of the dentition, the target area of tooth nerves shrinks with age, and these nerves show marked pathological-like changes. Nerve growth factor and possibly also brain-derived neurotrophic factor seem to be important in the formation of a sensory pulpal innervation. Neurotrophin-3 and -4/5 are probably not involved. In addition, glial cell line-derived neurotrophic factor, but not neurturin, seems to be involved in the control of pulpal axon growth. A variety of other growth factors may also influence developing tooth nerves. Many major extracellular matrix molecules, which can influence growing axons, are present in developing teeth. It is likely that these molecules influence the growing pulpal axons.
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| 8. |
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| 9. |
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| 10. |
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| 11. |
- Hildebrand, Claes, et al.
(författare)
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The structure of myelinated axons in the CNS
- 2005. - 1
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Ingår i: Multiple Sclerosis As A Neuronal Disease. - New York : Elsevier Academic Press. - 0127387617 - 9780127387611 ; , s. 1-28
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This book examines the role of neurons in multiple sclerosis (MS) and the changes that occur in neurons as a result of MS. It places MS in a new and important perspective that not only explains the basis for symptom production, remission, and progress in MS, but also promises to open up new therapeutic possibilities. * Brings together the latest information from clinical, pathological, imaging, molecular, and pharmacological realms to explore the neurobiology of Multiple Sclerosis* Places MS in a new and important perspective that promises to open up new therapeutic avenues* Superbly illustrated and referenced
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| 12. |
- Hildebrand, Claes, 1941-, et al.
(författare)
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Tusen miljarder dynamiska individer
- 2000
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Ingår i: Läkartidningen. - 0023-7205 .- 1652-7518. ; 97, s. 2952-2954
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 13. |
- Hoe-Hansen, Carsten, et al.
(författare)
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Acute local inflammation elicits sprouting of sensory axons in the rat supraspinatus tendon
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Inflammation activates nociceptive nerve endings and can elicit local sprouting of axons. We hypothesized that axon sprouting might be one factor behind the emergence of painful inflammatory conditions in the shoulder. Here we examine the distribution of sensory and sympathetic axons in the rat subacromial space under normal conditions and after local induction of inflammation with carrageenan. Furthermore, we measured the neuropeptide content in the supraspinatus tendon. In normal rats protein gene product 9.5- (POP 9.5-), substance P- (SP-), calcitonin gene related peptide- (CGRP-), neuropeptide Y- (NPY-) and tyrosine hydroxylase- (TH-) like immunoreactive (LI) axon profiles occurred in the subacromial space and around the glenohumeral joint. In the supraspinatus tendon axon profiles were limited to the tendon-muscle junction. After carrageenan injection inflammatory cells invaded the tendon and the subacromial bursa with a maximum at 2-3 weeks. Moreover, the tendon and the bursa showed signs of sprouting of PGP-9.5-, SP- and CGRP-LI axons, but not NPY- and TH-LI axons. The tendon was also invaded by blood vessels. The occurrence of axon profiles had a maximum at 2 weeks after injection and then subsided. Also, these axons were GAP-43-LI indicating collateral sprouting of nociceptive nerve fibres. There was no significant increase in the concentration of the neuropeptides SP and CGRP in the supraspinatus tendon. No inflammatory reaction or sprouting of nerve fibres was seen in saline-injected controls. We conclude that an acute inflammation in the subacromial space of the rat shoulder region can elicit a transient local sprouting of sensory axons in the tendon stroma and associated aberrant blood vessels.
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| 14. |
- Hoe-Hansen, Carsten, et al.
(författare)
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Increased Occurrence of Nerve Fibres and some Neuropeptides in Subacromial Tissue Biopsies from Patients with Impingement Syndrome of the Shoulder
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Background: The pathophysiology of subacromial inflammation is not fully understood. In the present study we evaluate the presence of sensory and sympathetic nerve fibres and some neuropeptides in biopsies from the supraspinatus tendon and the subacromial bursa of patients with chronic subacromial inflammation as well as of control cases.Methods: The occurrence of nerve fibres was subjectively assessed by immunohistochemistry. The concentration of substance P (SP), calcitonin generelated peptide (CGRP) and neuropeptide Y (NPY) was measured by radioimmunoassay (RIA).Results: In tendon biopsies from patients with an intact or partially ruptured tendon protein gene product 9.5-like immunoreactive (LI), SP-LI and CGRP-LI nerve fibres were abnormally abundant. In patients with a total tendon rupture nerve fibre occurrence was normal. All biopsies from the bursa exhibited an abnormally high occurrence of SP- and CGRP-LI nerve fibres. In all biopsies the tendon and the bursa contained more blood vessels than normal. The vessels were surrounded by NPY- and tyrosine hydroxylase-LI nerve fibres in a subjectively normal pattern. RIA analysis revealed that the concentration of all three neuropeptides was abnormally high in tendon biopsies from patients with an intact or partially ruptured tendon. Tendon biopsies from patients with total tendon rupture showed statistically normal levels. Biopsies from the bursa showed abnormally high levels of SP and CGRP but normal levels of NPY in all patients.Conclusion: We conclude, that the supraspinatus tendon and the subacromial bursa exhibit an increased occurrence of nerve fibres and some neuropeptides in patients with chronic subacromial inflammation.Clinical relevance: Patients with chronic subacromial inflammation have a disabling pain problem. The increased local occurrence of sensory andsympathetic axons in the inflamed tissues as well as the elevated tissue concentration of certain neuropeptides may represent important factors behind that problem.
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| 15. |
- Jamali, Reza, 1967-
(författare)
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Peripheral Hypoglycaemic Neuropathy in Type 1 Diabetic Rats : Morphologic and Metabolic Studies
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hyperglycaemia caused by insulin deficiency is believed to play a major role in the de-velopment of neuropathy in diabetic patients. The clinical and pathological features of diabetic neuropathy vary considerably, although sensory and autonomic dysfunctions are the most common characteristics. Normalisation of the blood glucose level by ef-fective insulin treatment decreases the incidence of diabetic neuropathy in patients. However, intensive insulin therapy may result in more frequent hypoglycaemic epi-sodes than are provoked by less ambitious diabetes control. Neuropathy might also be induced by severe hypoglycaemia in diabetes or insulinoma. Accordingly, it seems that the diversity in clinical symptoms of diabetic neuropathy may be due to the combined effects of hyperglycaemia and hypoglycaemia. Based on that assumption, the general aim of this project was to study the relationship between severe hypoglycaemia and pe-ripheral neuropathy in diabetic rats. To understand how the development of neuropathy is related to glycaemic control, we needed to be aware of the glucose dynamics in the animal model that we used. The aim was to ascertain whether the diabetic rats were similar to type 1 diabetic patients with regard to such dynamics. To achieve that goal, we used a MiniMed continuous glucose monitoring system (CGMS®) to measure sub-cutaneous glucose in freely moving rats over a period of 72 hours. The glucose monitor worked well, and it showed that the insulin-treated diabetic BB/Wor rats with a hyper-glycaemic insulin regimen have a glycaemic status similar to that of type 1 diabetic patients with poor glycaemic control. The diabetic rats with a hypoglycaemic regimen generally had low blood glucose levels.Prolonged hypoglycaemia led to axonal de- and regeneration of large myelinated fibres in vagus nerve destined to the laryngeal muscle. Axonal de- and regeneration was also observed in the gastrocnemius and sural nerves, although the frequency of degeneration was much lower in the sural nerve. Small myelinated and unmyelinated nerve fibres were normal in these nerves. These results suggest that hypoglycaemia preferentially damages muscle-related nerve fibres. In contrast, in the diabetic rats exposed to pro-longed hyperglycaemia, only the sural nerve exhibited decreased myelinated fibre diameter in the absence of obvious axonal degeneration.In situ glucose measurements by microdialysis showed that the glucose concentrations in blood and subcutaneous tissue were similar in healthy, diabetic hyperglycaemic, and diabetic hypoglycaemic rats. In the healthy and hyperglycaemic animals, the lowest glucose level was found in the peripheral nerve. Moreover, in controls, the glucose level was lower in muscle than in blood. In hypoglycaemic rats, there were no signifi-cant differences in glucose concentrations between different tissues.
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| 16. |
- Jergovic, Davor, 1959-, et al.
(författare)
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Changes in a rat facial muscle after facial nerve injury and repair
- 2001
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Ingår i: Muscle and Nerve. - : John Wiley & Sons. - 0148-639X .- 1097-4598. ; 24:9, s. 1202-1212
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Tidskriftsartikel (refereegranskat)abstract
- This study describes changes in a rat facial muscle innervated by the mandibular and buccal facial nerve branches 4 months after nerve injury and repair. The following groups were studied: (A) normal controls; (B) spontaneous reinnervation by collateral or terminal sprouting; (C) reinnervation after surgical repair of the mandibular branch; and (D) chronic denervation. The normal muscle contained 1200 exclusively fast fibers, mainly myosin heavy chain (MyHC) IIB fibers. In group B, fiber number and fiber type proportions were normal. In group C, fiber number was subnormal. Diameters and proportions of MyHC IIA and hybrid fibers were above normal. The proportion of MyHC IIB fibers was subnormal. Immediate and delayed repair gave similar results with respect to the parameters examined. Group D rats underwent severe atrophic and degenerative changes. Hybrid fibers prevailed. These data suggest that spontaneous regeneration of the rat facial nerve is superior to regeneration after surgical repair and that immediacy does not give better results than moderate delay with respect to surgical repair. Long delays are shown to be detrimental.
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| 17. |
- Jergovic, Davor, et al.
(författare)
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Repair of the mandibular branch of the rat facial nerve through transmedian grafting in one or two stages : Morphological evaluation
- 1997
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Ingår i: Journal of the peripheral nervous system. - 1085-9489 .- 1529-8027. ; 2:2, s. 181-188
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Tidskriftsartikel (refereegranskat)abstract
- This study examined by electron microscopy the normal fibre composition of the mandibular branch (MB) of the rat facial nerve and the outcome of axon regeneration in the MB after transmedian grafting in one or two stages. The average normal MB contained 2,185 axons, 17 % of which were unmyelinated. The myelinated axons had a unimodal diameter distribution (range 1.5-9.5 μm, mode 4.5 μm). After superior cervical ganglionectomy, the MB lost 1/3 of the C-fibres and 10% of the myelinated axons. In neonatally capsaicin-treated rats the occurrence of unmyelinated axons was reduced by about 50%. After repair in one or two stages the MB contained more myelinated and unmyelinated axons than normal. The myelinated axons showed a unimodal size distribution with a subnormal diameter range. Statistical comparisons showed that MBs from both experimental groups were significantly abnormal with respect to total axon number as well as numbers of unmyelinated and myelinated axons. In these respects the grafted MBs did not differ significantly from each other. However, the myelinated axons in MBs from one-stage cases showed larger mean and maximum diameters compared to MBs from two-stage cases. These data suggest that the normal MB of the rat contains myelinated and unmyelinated sympathetic axons and that about half the C-fibres in the normal MB come from capsaicin-sensitive sensory neurons. The comparison of the two reparative procedures used provides evidence in favor of the one-stage alternative.
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| 18. |
- Jergovic, Davor, et al.
(författare)
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Repair of the mandibular branch of the rat facial nerve through transmedian grafting in one or two stages : Functional evaluation
- 1998
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Ingår i: Journal of the peripheral nervous system. - 1085-9489 .- 1529-8027. ; 3:1, s. 54-62
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Tidskriftsartikel (refereegranskat)abstract
- A previous study examined the morphological outcome of axonal regeneration in the mandibular branch (ramus marginalis mandibulae) of the rat facial nerve after transmedian nerve grafting in one or two stages. The present study supplements the morphological data with a functional evaluation. Recordings of the force of tetanic muscle contractions elicited through stimulation of the mandibular branch showed that upper and lower lip data obtained from animals grafted in one stage did not differ significantly from control data. However, animals grafted in two stages exhibited significantly lower muscle forces compared to one-stage data and to control data. Electromyographic recordings of the M-response showed multiple prolonged potential fluctuations with subnormal amplitudes in grafted cases. In both groups of grafted rats, the mean voltage amplitudes recorded from the upper lip were weaker than the amplitudes seen at the angle of the mouth or the lower lip. The two-stage cases exhibited the most obvious deficit. In conclusion, the present results show that, with respect to the functional restoration achieved three months after nerve injury, repair through transmedian grafting in one stage gives better results than repair in two stages. This finding, which conforms with previous morphological data, suggests that the one-stage procedure should be considered for clinical use.
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| 19. |
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| 20. |
- Jerregård, Helena, et al.
(författare)
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Fibroblast-like cells from rat plantar skin and neurotrophin-transfected 3T3 fibroblasts influence neurite growth from rat sensory neurons in vitro
- 2001
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Ingår i: Journal of Neurocytology. - 0300-4864 .- 1573-7381. ; 29:9, s. 653-663
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Tidskriftsartikel (refereegranskat)abstract
- Our previous finding that skin-derived and muscle-derived molecules can be used to sort regenerating rat sciatic nerve axons evoked questions concerning neuron-target interactions at the level of single cells, which prompted the present study. The results show that dorsal root ganglion (DRG) neurons co-cultured with fibroblast-like skin-derived cells emit many neurites. These have a proximal linear segment and a distal network of beaded branches in direct relation to skin-derived cells. Electron microscopic examination of such co-cultures showed bundles of neurites at some distance from the target cells and single profiles closely apposed to subjacent cells. RNase protection assay revealed that cultivated skin-derived cells express nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and neurotrophin-4 (NT-4). In co-cultures of DRG neurons and 3T3 fibroblasts overexpressing either of the neurotrophins produced by skin-derived cells the picture varied. NT-3 transfected 3T3 fibroblasts gave a growth pattern similar to that seen with skin-derived cells. Neurons co-cultured with mock-transfected 3T3 fibroblasts were small and showed weak neurite growth. In co-cultures with a membrane insert between skin-derived cells or 3T3 fibroblasts and DRG neurons few neurons survived and neurite growth was very sparse. We conclude that skin-derived cells stimulate neurite growth from sensory neurons in vitro, that these cells produce NGF, BDNF, NT-3 and NT-4 and that 3T3 fibroblasts producing NT-3 mimic the effect of skin-derived cells on sensory neurons in co-culture. Finally the results suggest that cell surface molecules are important for neuritogenesis.
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| 21. |
- Jerregård, Helena, et al.
(författare)
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Sorting of Regenerating Rat Sciatic Nerve Fibers with Target-Derived Molecules
- 2001
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Ingår i: Experimental Neurology. - : Elsevier BV. - 0014-4886 .- 1090-2430. ; 169:2, s. 298-306
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Tidskriftsartikel (refereegranskat)abstract
- The functional outcome of microsurgical repair of divided nerves is disappointing since many regenerating axons fail to reach appropriate targets. Sorting of regenerating axons according to target tissue might be used to improve functional regeneration. The aim of the present study is to see if regenerating axons can be sorted into functionally different bundles with target-derived molecules. The proximal stump of the adult rat sciatic nerve was sutured into the inlet of a silicon Y-tube. The two branches of the Y-tube were filled with agarose primed with filtrates prepared from skin and muscle homogenates from the operated rat. The tibial and sural nerves were inserted in the two branches of the Y-tube. Six weeks later the sciatic nerve axons showed vigorous regeneration into both branches. Electron microscopic examination of regenerated nerve segments showed numerous myelinated and unmyelinated axons. The proportion of myelinated axons was significantly larger in the muscle-gel branch than in the skin-gel branch. Retrograde tracing from the nerve regenerates with Fast Blue and Fluoro-Ruby showed that ventral horn neurons at L4–L5 segmental levels were preferentially labeled from the muscle-gel branch. Neurons in corresponding dorsal root ganglia were labeled from both Y-tube branches (no significant numerical difference). A few neurons of both types contained both tracers. Measurements revealed that sensory neurons labeled from the muscle-gel branch were significantly larger (mean perikaryal area 870 μm2) than neurons labeled from the skin-gel branch (mean area 580 μm2). We conclude that regenerating motor and sensory axons can be sorted with target-derived molecules.
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| 22. |
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| 23. |
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| 24. |
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| 25. |
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| 26. |
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| 27. |
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| 28. |
- Lillesaar, Christina, 1975-, et al.
(författare)
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Denervation does not affect the growth of rat vibrissae
- 1999
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Ingår i: Neuroscience Letters. - 0304-3940 .- 1872-7972. ; 261:1-2, s. 69-72
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Tidskriftsartikel (refereegranskat)abstract
- This study examines the hypothesis that neural factors influence the growth of rat vibrissae. We divided the vibrissae in rows α-δ, 1 and 2 and examined their regrowth during the first complete growth period in normal and nerve-lesioned rats. The lesions used were denervation through neonatal capsaicin treatment, surgical sympathecomy in adult rats, neurectomy of the mandibular and buccal branches of the facial nerve in adult rats or division of the infraorbital nerve in adult rats. Normal vibrissae developed a length of 51.1 mm and a diameter of 178 μm (row α-δ), 44.1 mm and 181 μm (row 1) and 33.2 mm and 165 μm (row 2). In all experimental groups the examined vibrissae developed a normal final length and proximal diameter. This indicates that local nerves do not influence vibrissal growth to any major extent.
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| 29. |
- Lillesaar, Christina, 1975-, et al.
(författare)
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Responses of rat trigeminal neurones to dental pulp cells or fibroblasts overexpressing neurotrophic factors in vitro
- 2003
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Ingår i: Neuroscience. - 0306-4522 .- 1873-7544. ; 119:2, s. 443-451
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Tidskriftsartikel (refereegranskat)abstract
- The adult dental pulp is innervated by sensory trigeminal axons and efferent sympathetic axons. Rat trigeminal ganglia extend neurites when co-cultivated in vitro with pulpal tissue explants, suggesting that pulpal cells secrete soluble molecules that stimulate the growth of trigeminal ganglion axons. In addition, cultured pulpal cells produce mRNAs for neurotrophins and glial cell line-derived neurotrophic factor-family members. These data suggest that neurotrophic factors are involved in the formation of a pulpal innervation. Here, we examine how pulpal cells and 3T3 fibroblasts overexpressing certain neurotrophic factors (nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, neurotrophin-4, glial cell line-derived neurotrophic factor or neurturin) influence survival and growth of single trigeminal ganglion neurones in vitro in quantitative terms. The results show that most of the neurotrophic factor-overexpressing fibroblasts induce similar neuronal soma diameters, but higher survival rates and neurite lengths compared with pulpal cells. With respect to neurite growth pattern, trigeminal ganglion neurones co-cultured with fibroblasts overexpressing nerve growth factor develop a geometry that is most similar to that seen in co-cultures with pulpal cells. We conclude that none of the fibroblasts overexpressing neurotrophic factors can fully mimic the effects of pulpal cells on trigeminal ganglion neurones, and that nerve growth factor promotes a neurite growth pattern most similar to the picture seen in co-cultures with pulpal cells.
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| 30. |
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| 31. |
- Mohseni, Simin, 1959-, et al.
(författare)
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Hypoglycaemic neuropathy : Occurrence of axon terminals in plantar skin and plantar muscle of diabetic BB/Wor rats treated with insulin implants
- 2000
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Ingår i: Acta Neuropathologica. - 0001-6322 .- 1432-0533. ; 99:3, s. 257-262
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Tidskriftsartikel (refereegranskat)abstract
- It is generally believed that diabetic neuropathy is due to chronic hyperglycaemia. However, experience from insulinoma patients and experimental studies show that hypoglycaemia may also cause neuropathy. Accordingly, the plantar nerves of diabetic eu-/hypoglycaemic BB/Wor rats treated with insulin implants exhibit a distinct neuropathy. To what extent hypoglycaemic neuropathy affects axon terminals in skin and muscle is unknown. In the present study we examine the occurrence of epidermal axon profiles and the neuropeptide calcitonin gene-related peptide (CGRP) in plantar skin, and of end plate axon terminals in a plantar muscle of diabetic BB/Wor rats subjected to long periods of hypoglycaemia. The number of protein gene product-immunoreactive axon profiles was found to be normal in heel skin biopsy specimens from eu-/hypoglycaemic rats, but many profiles were short and thin. The content of CGRP in the skin biopsy samples was significantly below normal. After staining with antibodies against the vesicular acetylcholine transporter protein, the occurrence of end plate axon terminals was significantly reduced in sections from the flexor hallucis brevis muscle of eu-/hypoglycaemic rats. Moreover, the end plate axon terminals tended to be abnormally small in these rats. We conclude that the hypoglycaemic neuropathy seen in plantar nerve trunks of diabetic BB/Wor rats treated with insulin implants is accompanied by mild alterations in the epidermal innervation of plantar skin and a more obviously abnormal nerve terminal pattern in plantar muscle.
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| 32. |
- Mohseni, Simin, et al.
(författare)
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Hypoglycaemic neuropathy in BB/Wor rats treated with insulin implants : Electron microscopic observations
- 1998
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Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 96:2, s. 151-156
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Tidskriftsartikel (refereegranskat)abstract
- Insulin-dependent diabetes mellitus is a chronic metabolic disease that causes long-term secondary complications such as neuropathy. The occurrence of diabetic neuropathy has generally been thought of as being associated with hyperglycaemia. However, in a previous light microscopic examination of plantar nerves in diabetic BB/Wor rats treated with insulin implants we found that eu-/hyperglycaemic rats present a normal picture, whereas eu-/hypoglycaemic rats show severe changes. The aim of the present work is to supplement our previous light microscopic report with electron microsocpic data from the lateral plantar nerve of normal, eu-/hyperglycaemic and eu-/hypoglycaemic BB/Wor rats. Under the electron microscope lateral plantar nerves collected from eu-/hyperglycaemic rats presented a qualitatively normal picture. In addition, the fibre numbers and the size distribution of the myelinated fibres were normal. In contrast, specimens from eu-/hypoglycaemic BB/Wor rats showed severe qualitative changes, interpreted as signs of axonal de- and regeneration. The total number of axons was somewhat subnormal and the sizes of the myelinated fibres were strongly shifted towards smaller diameters. These data confirm our previous light microscopic observations. We conclude that eu-/hypoglycaemic BB/Wor rats treated with insulin implants, but not similarly treated eu-/hyperglycaemic animals, develop a neuropathy in their plantar nerves.
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| 33. |
- Mohseni, Simin, et al.
(författare)
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Neuropathy in diabetic BB/Wor rats treated with insulin implants
- 1998
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Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 96:2, s. 144-150
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Tidskriftsartikel (refereegranskat)abstract
- To elucidate the pathophysiology of diabetic neuropathy many workers have examined nerve specimens from diabetic rats. While most workers found that animals with high blood glucose levels develop neuropathy, some researchers report that the peripheral nerves are normal in hyperglycaemic rats. Hypoglycaemia may also cause neuropathy. Some workers suggest that neuropathy is linked to fluctuations of the blood glucose level. In the present study we examine plantar nerves of diabetic BB/ Wor rats maintained on an eu-/hyperglycaemic or an eu-/ hypoglycaemic regime with insulin implants. Treatment with implants worked well. Light microscopic examination of nerve fibres in non-diabetic control rats and in eu-/ hyperglycaemic diabetic rats showed a normal picture. Preparations from eu-/hypoglycemic rats showed irregular myelin sheaths and signs of Wallerian degeneration. The lengths and diameters of the largest internodes were significantly subnormal. We conclude, that periodic moderate hypoglycaemia, but not periodic moderate hyperglycaemia, elicits neuropathy in diabetic BB/Wor rats treated with insulin implants.
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| 34. |
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| 35. |
- Norlin, Rolf, et al.
(författare)
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Shoulder region of the rat : Anatomy and fiber composition of some suprascapular nerve branches
- 1994
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Ingår i: The Anatomical Record. - : Wiley. - 1932-8486 .- 0003-276X. ; 239:3, s. 332-342
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Tidskriftsartikel (refereegranskat)abstract
- Background: The pathophysiology of chronic supraspinatus tendinitis is not fully understood. This may be due to the scarcity of experimental studies on this issue.Methods: In search for a system suitable for experimental analysis, the present study describes the relevant gross anatomy of the rat shoulder region (dissection), and examines the fiber composition of relevant suprascapular nerve branches (electron microscopy, selective denervations).Results: The rat shoulder region is similar to the human shoulder in terms of gross anatomy. The average suprascapular nerve (SSC) is derived mainly from the spinal cord segment C5 and contains 3,435 axons, 74% of which are unmyelinated. The supraspinatus branch (SSP) contains 627 fibers. Of the SSP fibers, 52% are myelinated, including 32% motor and 20% sensory axons. Of the C-fibers in the SSP 16% are sympathetic efferents and 32% are sensory. Many of the latter disappear after neonatal capsaicin treatment. The SSC emits a subacromial articular branch (ART), with some 260 axons, about 90% of which are unmyelinated. The myelinated ART fibers are sensory, and of the unmyelinated ones about 24% are sympathetic efferents and 66% are afferents. The latter resist neonatal capsaicin treatment.Conclusions: In view of the anatomy of the supraspinatus muscle, of the subacromial space, and of relevant nerves, the rat shoulder should be appropriate for experimental studies on inflammatory conditions in the subacromial space.
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| 36. |
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| 37. |
- Stankovic, Nenad, et al.
(författare)
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Indirect effect of sciatic nerve injury on the epidermal thickness of plantar glabrous skin in rats
- 1999
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Ingår i: Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery. - : Taylor & Francis. - 0284-4311 .- 1651-2073. ; 33:3, s. 273-279
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Tidskriftsartikel (refereegranskat)abstract
- In patients with nerve injuries, the skin over the denervated part tends to atrophy. Few experimental studies have dealt with this issue. In this paper we examine the effects of nerve injury on the epidermis in plantar glabrous skin in rats. Analysis of paraffin sections showed that the epidermis becomes abnormally thin after sciatic neurotomy and suture or neurectomy, but not after nerve crush. Autoradiographic analysis showed a subnormal number of thymidine-labelled epidermal cells in plantar skin of rats subjected to sciatic neurectomy. However, after selective division of the sciatic foot branches, with preserved function of thigh and leg muscles, the number of labelled epidermal cells did not differ significantly between the side operated on and the control side. We conclude that the effect of sciatic nerve division on plantar skin in rats is caused by the motor deficiency in the foot rather than by deficient innervation of the skin.
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