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- Edoff, Karin, 1973-, et al.
(författare)
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Neuropeptide content and physiological properties of rat cartilage-projecting sensory neurones co-cultured with perichondrial cells
- 2001
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Ingår i: Neuroscience Letters. - 0304-3940 .- 1872-7972. ; 315:3, s. 141-144
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Tidskriftsartikel (refereegranskat)abstract
- In young rats the cartilaginous epiphyses forming the knee joint are supplied with blood vessels and peptidergic sensory nerve fibres through the perichondrium and cartilage canals. In the present study we show that cartilage-related dorsal root ganglion neurones co-cultured with perichondrial cells develop extensive neurite trees and express calcitonin gene-related peptide (CGRP) and substance P (SP) in in vivo-like proportions using retrograde tracing and immunohistochemistry. Moreover, whole cell patch clamp recordings from these cells showed that the majority is depolarised by application of H+-ions. These results are compatible with the hypothesis that a local imbalance of blood flow and metabolism during normal skeletal maturation may cause tissue acidosis eliciting release of CGRP/SP from sensory nerve endings.
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| 2. |
- Edoff, Karin, 1973-, et al.
(författare)
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Effects of IL-1β, IL-6 or LIF on rat sensory neurons co-cultured with fibroblast-like cells
- 2002
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Ingår i: Journal of Neuroscience Research. - : Wiley. - 0360-4012 .- 1097-4547. ; 67:2, s. 255-263
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Tidskriftsartikel (refereegranskat)abstract
- Inflammation may affect the local presence of sensory nerve fibers in situ and inflammatory mediators influence sensory neurons in vitro. In the present study we have investigated effects of the cytokines interleukin-1β (IL-1β, interleukin-6 (IL-6), and leukemia inhibitory factor (LIF) on survival of and neurite growth from neonatal rat sensory neurons co-cultured with fibroblast-like cells prepared from neonatal rat skin (sFLCs) or perichondrium (pFLCs). The results showed that both FLC types expressed receptors for all three cytokines. Five ng/ml of either cytokine, but not lower or higher concentrations, supported survival of DRG neurons co-cultured with sFLCs. Neuronal survival was also enhanced by addition of the soluble IL-6 receptor (rsIL-6R) with or without IL-6. In co-cultures with pFLCs neuronal survival was promoted by IL-6, increasing with cytokine concentration. Addition of rsIL-6R without IL-6 did also stimulate neuronal survival. The growth of neurites from DRG neurons co-cultured with sFLCs was stimulated by 0.5 ng/ml LIF, unaffected by 5 ng/ml LIF and inhibited by 50 ng/ml LIF. Considering DRG neurons co-cultured with pFLCs, 50 ng/ml of either of the three cytokines, as well as rsIL-6R conditioned medium, stimulated neurite outgrowth. Some of the cytokine effects observed were reduced by application of antibodies against nerve growth factor (NGF). We conclude that that the cytokines examined affect DRG neurons in terms of survival or neuritogenesis, that the effects are influenced by cytokine concentration and the origin of the FLCs and that some of the effects are indirect, probably being mediated by factors released from FLCs.
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| 3. |
- 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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| 4. |
- 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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| 5. |
- Edoff, Karin, 1973-
(författare)
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Sensory nerve fibres, neuropeptides and cartilage : Experimental studies in the rat
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During development, maintenance and repair after injury, reciprocal interactions occur between the peripheral nervous system and the target tissues. In the Papers presented in this thesis, different aspects of such netvetarget influences between peripheral nerve fibres and skeletal tissues dtuing development and repair have been investigated in the rat. Developing rat cartilaginous bone primordia have a richly innervated and vascularised perichondriwn. In addition, larger bones exhibit cartilage canals containing blood vessels and putative sensory nerve fibres. Tills evoked the question if there is a nervous regulation of skeletal development. Denervation of the hind paws of young rats resulted in a deficient length growth but had no influence on the progress of secondary ossification. Since growth is mainly due to events in cartilage, cartilage projecting sensory neurones were identified and examined. Sensory neurones projecting to the rat cartilaginous distal femoral epiphyses were located mainly in the dorsal root ganglia (DRG) L3 and L4 and exhibited small or medium-sized diameters. A large proportion of these neurones contained the neuropeptides CGRP and/or SP. However, application of CGRP to cartilage explants in vitro did not stimulate the chondrocytes in terms of an elevation of the level of cyclic AMP. Another possibility would be that the neuropeptides affect the developmental growth of bone and chondrocytes indirectly via effects on the blood vessels. Experiments .involving tracing as above and eo-culture of labelled DRG neurones and perichondrial cells in combination with immunohistochenllstty or electrophysiology showed that the traced cultured neurones contained CGRP and/or SPin in vivo-like proportions and that most of the cartilage-projecting neurones were proton sensitive, This prompted the suggestion that the nerve fibres in the perichondrium and in cartilage canals might release CGRP and SP in response to local tissue acidosis, thereby promoting tissue homeostasis by monitoring the balance between vascular supply and metabolic load and by influencing angiogenesis and blood flow. Subsequently, possible target influences on the local presence of perichondrial sensory nerve fibres were investigated. Application of inflammation related cytokines (IL-1ß, IL-6 and LIF) affected sensory neurones eo-cultured with perichondrium- or skin-derived fibroblast-like cells in terms of survival and neurite growth. These effects were strongly influenced by the origin of the target cells. Finally, experiments using the adult rat patella showed that osteochondral defects heal spontaneously but incompletely and that healing is not accompanied by an increase of local nerve fibres at the times examined. In conclusion, the present results indicate that cartilagerelated sensory nerve fibres influence skeletal growth, that a high proportion of these neurones contain CGRP and SP, that CGRP does not activate chondrocytes in cartilage slices, that many cartilage related sensory nerve fibres are proton-sensitive· and likely have a vasoregulatory role, that inflammatory mediators have distinct effects on sensory neurones eo-cultivated with perichondrial cells and that healing of an osteochondral defect in the rat patella does not involve a local increase of cartilage-related nerve fibres.
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