| Central nervous system(CNS)axonal regeneration after injury is so difficult,has been the difficult clinical treatment of neurological for a long time.There were many ways and varieties of reasons had been found to overcome the difficulties.In recent years,studies have shown that,the CNS axons can not be renewable after damage may be a few reasons: adult neuronal regeneration after injury reduced ability itself;glial scar formation;the lack of neurotrophic factors and axon regeneration inhibitory proteins role,and so on.The functions of the central nervous system repair after injury,there is no effective way currently but only rely on its own repair capabilities.The clinical treatment is only a number of supplementary measures,and the results are not satisfactory.Endothelial lipase(EL)is a newly described member of the triglyceride lipase gene family.Endothelial lipase was cloned by two grops using similar methodologies.One group was led by Hirata in 1999.The employed suppression subtraction hybridization to characterize the genetic basis for endothelial cell mediated vascular formation.The cloning strategy was to isolate genes that were preferentially expressed to growth-arrested HUVEC monolayers.In the same year,Jaye and his colleagues cloned the gene from THP-1 cells which were exposed to oxidized low density lipoprotein(ox-LDL).This new gene has a considerable molecular homology with lipoprotein lipase(LPL)(44%),hepatic lipase(HL) (41%)and pancreas lipase(31%).These findings suggested this new gene encode productions which belong to trilyceride lipase gene family along with LPL and HL.This production was named endothelial lipase and the gene was named LIPG according to the gene nomenclature of this family.Now there are many unclear things about endothelial lipase.The study of endothelial lipase is carrying through abroad.But,there is no repore about endothelial lipase in our country.What is the lipolytic characterization of endothelial lipase?Objective Established the CNS injury model in vivo and vitro,research into the CNS injury on expression of endothelial lipase,to explore the role of endothelial lipase in the regeneration and repair of axons of CNS after mechanical injury.Methods In this study,we established two central nervous system injury model in vivo and vitro.Purified cultures of cortical astrocytes were prepared from neonatal rats (P0-P3),based on the differential properties of developmental time-coure and cellular adhesions.Established astrocytes mechanical injury model,the expression of endothelial lipase in injured astrocytes from 0H,1H,3H,6H,12H,24H,48H and normal astrocytes were observed and examined by immunocytochemical staining and western blot assay. Male adult SD rats were randomly divided into experimentation;established the hemisection spinal cord injury with reference to the methord of Tuszynski.Collected the spinal cord tissue of different time points(12H,1D,3D,5D,1W,2W,and 4W),shamoperated group(Cont)and normal(N) spinal cord tissure.Detected the expression of endothelial lipase by western blot and immunohistochemistry,and its relationship with apoptosis-promoting factor of caspase-3.Results The expression of endothelial lipase began to increase after mechanical injury of astrocytes,and at 6H it reached the peak,and increased at the fifth day post-SCI, compared with the control group difference was significant,P＜0.01,then the expression declined.The expression of caspase-3 increased at 1H after injury of astrocytes and reached the peak,compared with the control group difference was significant,P＜0.01,then the expression declined;by 1D after injury of spinal cord,the expression of caspase-3 was markedly increased,compared with the control group difference was significant,P＜0.01, then the expression declined.Conclusion Apoptosis in injured spinal cord tissure and mechanical injury astrocytes early;endothelial lipase may have important implications in the repair and regeneration of CNS following injury. |
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