| 1. |
- Sharma, Aruna, et al.
(författare)
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Cold Environment Exacerbates Brain Pathology and Oxidative Stress Following Traumatic Brain Injuries : Potential Therapeutic Effects of Nanowired Antioxidant Compound H-290/51
- 2018
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Ingår i: Molecular Neurobiology. - : Humana Press. - 0893-7648 .- 1559-1182. ; 55:1, s. 276-285
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Tidskriftsartikel (refereegranskat)abstract
- The possibility that traumatic brain injury (TBI) occurring in a cold environment exacerbates brain pathology and oxidative stress was examined in our rat model. TBI was inflicted by making a longitudinal incision into the right parietal cerebral cortex (2 mm deep and 4 mm long) in cold-acclimatized rats (5 degrees C for 3 h daily for 5 weeks) or animals at room temperature under Equithesin anesthesia. TBI in cold-exposed rats exhibited pronounced increase in brain lucigenin (LCG), luminol (LUM), and malondialdehyde (MDA) and marked pronounced decrease in glutathione (GTH) as compared to identical TBI at room temperature. The magnitude and intensity of BBB breakdown to radioiodine and Evans blue albumin, edema formation, and neuronal injuries were also exacerbated in cold-exposed rats after injury as compared to room temperature. Nanowired delivery of H-290/51 (50 mg/kg) 6 and 8 h after injury in cold-exposed group significantly thwarted brain pathology and oxidative stress whereas normal delivery of H-290/51 was neuroprotective after TBI at room temperature only. These observations are the first to demonstrate that (i) cold aggravates the pathophysiology of TBI possibly due to an enhanced production of oxidative stress, (ii) and in such conditions, nanodelivery of antioxidant compound has superior neuroprotective effects, not reported earlier.
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| 2. |
- Sharma, Hari Shanker, et al.
(författare)
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A New Antioxidant Compound H-290/51 Attenuates Nanoparticle Induced Neurotoxicity and Enhances Neurorepair in Hyperthermia
- 2010
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Ingår i: Brain Edema XIV. - Vienna : Springer. - 9783211987582 - 9783211988114 ; , s. 351-357
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Konferensbidrag (refereegranskat)abstract
- Previous reports from our laboratory show that animals treated with engineered nanoparticles derived from metals for 1 week and subjected to hyperthermia showed enhanced neurotoxicity in teens of blood-brain barrier (BBB) disruption, brain edema formation and cell injury. It appears that nano-particle induced enhanced oxidative stress leads to increased lipid peroxidation and over-production of hydroxyl radicals are responsible for exacerbation of neurotoxicity in hyperthermia. Therefore, in this investigation, rats (after 1 week administration of Ag or Cu nanoparticles) were treated with a new antioxidant compound H-290/51 (an inhibitor of lipid peroxidation, 50 mg/kg, p.o.) before subjecting them to hyperthermia. One group of nanoparticle treated rat received H-290/51 and were kept at room temperature for comparison. Our results show that H-290/51 significantly attenuated heat stress induced BBB impairment, brain edema formation and neurotoxicity in nanoparticle treated rats. However, no significant diminution of nanoparticle induced BBB breakdown, or neurotoxicity was observed in H-290/51 treated rats kept at room temperature. These observations suggest that nanoparticles aggravate oxidative stress following hyperthermia leading to exacerbation of neurotoxicity through oxidative stress-related mechanisms, not reported earlier.
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| 3. |
- Sharma, Hari Shanker, et al.
(författare)
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Alterations in Blood-Brain Barrier Function and Brain Pathology by Morphine in the Rat. Neuroprotective Effects of Antioxidant H-290/51
- 2010
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Ingår i: Brain Edema XIV. - Vienna : Springer. - 9783211987582 - 9783211988114 ; , s. 61-66
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Konferensbidrag (refereegranskat)abstract
- The possibility that stress associated with morphine administration or withdrawal will influence the blood-brain barrier (BBB) dysfunction, brain edema formation and brain pathology was examined in a rat model. Repeated daily administration of morphine (10 mg/kg, i.p.) resulted in drug dependence in rats on the 6th day and onwards. The BBB permeability to Evans blue albumin (EBA) and radioiodine ([131])Iodine did not alter during morphine dependence up to the 12th day. On the other hand, spontaneous withdrawal of morphine on day 1 resulted in profound stress symptoms and breakdown of the BBB to protein tracers in several brain regions. This increase in BBB to protein tracers was most pronounced on the 2nd day of morphine withdrawal. These rats also exhibited marked brain edema and abnormal neuronal and glial cell responses. Pretreatment with an antioxidant H-290/51 markedly attenuated the BBB dysfunction, brain edema formation and brain pathology during morphine withdrawal phases. These observations suggest that psychostimulants and associated oxidative stress are capable to induce brain pathology through modifying the BBB function.
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| 4. |
- Sharma, Hari Shanker, et al.
(författare)
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Chronic Treatment with Nanoparticles Exacerbate Hyperthermia Induced Blood-Brain Barrier Breakdown, Cognitive Dysfunction and Brain Pathology in the Rat : Neuroprotective Effects of Nanowired-Antioxidant Compound H-290/51
- 2009
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Ingår i: Journal of Nanoscience and Nanotechnology. - 1533-4880 .- 1533-4899. ; 9:8, s. 5073-5090
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Tidskriftsartikel (refereegranskat)abstract
- The possibility that chronic exposure of nanoparticles may alter stress reaction and brain pathology following hyperthermia was examined in a rat model. Engineered nanoparticles from Ag or M Cu (approximate to 50-60 nm) were administered (30 mg/kg, i.p.) once daily for 1 week in young male rats. M On the 8th day these animals were subjected to 4 h heat stress at 38 degrees C in a BOD incubator. In these animals stress symptoms, blood-brain barrier (BBB) permeability, cognitive and motor functions and brain pathology were examined. Subjection of nanoparticle treated rats to heat stress showed exacerbation of stress symptoms i.e., hyperthermia, salivation and prostration and exhibited greater BBB disruption, brain edema formation, impairment of cognitive and motor functions M and brain damage compared to normal animals. This enhanced brain pathology in heat stress was most marked in animals that received Ag nanoparticles compared to Cu treatment. Treatment with antioxidant compound H-290/51 either 30 min or 60 min after heat stress did not alter hyperthermia M induce brain pathology in nanoparticle treated rats. Whereas, administration of nanowired-H-290/51 after 30 min or 60 min heat stress markedly attenuated BBB disruption, sensory motor function and brain pathology. These results suggest that chronic nanoparticles treatment exacerbate hyperthermia induced brain pathology that is significantly attenuated by nanowired but not normal H-290/51 compound. Taken together, our observations suggest that nano-wired drug delivery of H-290/51 is a promising approach to induce neuroprotection in hyperthermia induced brain pathology, not reported earlier.
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| 5. |
- Sharma, Hari Shanker, et al.
(författare)
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Drugs of abuse-induced hyperthermia, blood-brain barrier dysfunction and neurotoxicity : neuroprotective effects of a new antioxidant compound H-290/51
- 2007
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Ingår i: Current pharmaceutical design. - : Bentham Science Publishers Ltd.. - 1381-6128 .- 1873-4286. ; 13:18, s. 1903-1923
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Forskningsöversikt (refereegranskat)abstract
- The psychostimulants, morphine and methamphetamine are well known drugs of abuse that induce brain pathology and/or neurodegeneration resulting in a huge burden on our society. The possible mechanisms of psychostimulants induced neuropathology and neurodegeneration are still not well known. The drugs of abuse results in profound hyperthermia and widespread alterations in neurochemical metabolism in the central nervous system (CNS). It appears that psychostimulants induced hyperthermia and/or release of neurochemicals influence the blood-brain barrier (BBB) dysfunction leading to brain pathology. The drugs of abuse also induce oxidative stress resulting in generation of free radicals and lipid peroxidation. Thus, further research is needed to understand the basic function of BBB disruption and temperature regulation by psychostimulants and to modify them pharmacologically to attenuate brain dysfunction and neuropathology. This review is focused on the problems of morphine and methamphetamine induced hyperthermia and their effects on breakdown of the BBB function leading to brain damage. Works done in our laboratory suggest that hyperthermia caused by these drugs is responsible for BBB disruption and neurodegeneration. This hypothesis is further supported by our observation that pretreatment with a portent antioxidant compound H-290/51 attenuates the BBB disruption and induces marked neuroprotection following morphine induced withdrawal and methamphetamine induced neurotoxicity. The possible mechanisms and functional significance of these findings are discussed.
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| 6. |
- Sharma, Hari Shanker, et al.
(författare)
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Neuroprotective effects of insulin like growth factor-1 on engineered metal nanoparticles Ag, Cu and Al induced blood-brain barrier breakdown, edema formation, oxidative stress, upregulation of neuronal nitric oxide synthase and brain pathology
- 2021
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Ingår i: Progress in Brain Research. - : Elsevier. - 0079-6123 .- 1875-7855. ; 266, s. 97-121, s. 97-121
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Tidskriftsartikel (refereegranskat)abstract
- Military personnel are vulnerable to environmental or industrial exposure of engineered nanoparticles (NPs) from metals. Long-term exposure of NPs from various sources affect sensory-motor or cognitive brain functions. Thus, a possibility exists that chronic exposure of NPs affect blood-brain barrier (BBB) breakdown and brain pathology by inducing oxidative stress and/or nitric oxide production. This hypothesis was examined in the rat intoxicated with Ag, Cu or Al (50–60 nm) nanoparticles (50 mg/kg, i.p. once daily) for 7 days. In these NPs treated rats the BBB permeability, brain edema, neuronal nitric oxide synthase (nNOS) immunoreactivity and brain oxidants levels, e.g., myeloperoxidase (MP), malondialdehyde (MD) and glutathione (GT) was examined on the 8th day. Cu and Ag but not Al nanoparticles increased the MP and MD levels by twofold in the brain although, GT showed 50% decline. At this time increase in brain water content and BBB breakdown to protein tracers were seen in areas exhibiting nNOS positive neurons and cell injuries. Pretreatment with insulin like growth factor-1 (IGF-1) in high doses (1 μg/kg, i.v. but not 0.5 μg/kg daily for 7 days) together with NPs significantly reduced the oxidative stress, nNOS upregulation, BBB breakdown, edema formation and cell injuries. These novel observations demonstrate that (i) NPs depending on their metal constituent (Cu, Ag but not Al) induce oxidative stress and nNOS expression leading to BBB disruption, brain edema and cell damage, and (ii) IGF-1 depending on doses exerts powerful neuroprotection against nanoneurotoxicity, not reported earlier.
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| 7. |
- Sharma, Hari Shanker, et al.
(författare)
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Silicon dioxide nanoparticles (SiO2, 40-50 nm) exacerbate pathophysiology of traumatic spinal cord injury and deteriorate functional outcome in the rat : An experimental study using pharmacological and morphological approaches
- 2009
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Ingår i: Journal of Nanoscience and Nanotechnology. - : American Scientific Publishers. - 1533-4880 .- 1533-4899. ; 9:8, s. 4970-4980
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Tidskriftsartikel (refereegranskat)abstract
- Silicon (SiO2) nanoparticles or silica dust is quite common form of exposure to soldiers engaged in gulf war that may influence their health and brain function. It is quite likely that traumatic injuries to the CNS may be influenced by exposure to these nanoparticles. However, the details of silicon nanoparticles on human health functions are still unknown. In this investigation we examined the effects of chronic silicon dioxide nanoparticles (SiO2, 40-50 nm) exposure on spinal cord injury (SCI) induced alterations on the functional outcome and the cord pathology in a rat model. Since nanoparticles induce oxidative stress, the influence of an antioxidant compound H-290/51 was also examined in these nanoparticles treated injured rats as well. Rats treated with SiO2 for 7 days did not show any significant alteration in behaviour on rota rod performances or on capacity angle tests. However, subjection of these nanoparticles exposed rats to SCI resulted in a profound deterioration in motor functions compared to normal rats with SCI. The magnitude of blood-spinal cord barrier (BSCB) disruption to Evans blue and radioiodine tracers and edema formation was much more aggravated following SCI in nanoparticles treated animals compared to untreated traumatized rats. Pretreatment with H-290/51 (50 mg/kg, p.o.) 30 min before SCI in nanoparticle treated rats did not alter spinal cord pathology or functional outcome, however, this dose of the compound was very effective in reducing pathophysiology of SCI in normal animals. These observations are the first to suggest that exposure of nanoparticles enhances the sensitivity of CNS to injuries and alter the effect of neuroprotective drugs.
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