Changes in neural stem cells and their derived supporting factor in injured spinal cord tissues of rats / 中国组织工程研究

ABSTRACT

AIM:Neural stem cells(NSCs)and their supporting factors are related to nerve regeneration after central nerve injury, but there are few evidences for the changes of NSCs and their derived supporting factors.This study explores the change of NSCs and gene expression of stem cell-derived neural stem/progenitor cell supporting factor(SDNSF)in the injured spinal cord tissues of rats,and investigates the relation between the NSCs and expressions of SDNSF. METHODS:The experiment was carried out in the laboratory of Nantong University Neuroscience Institute between September 2005 and March 2006.①A total of 27 SD rats,cleaning grade,were offered by the Animal Experimental Center of Nantong University.Twelve rats used for immunohistochemistry assay were divided into sham operation group and spinal cord injury group,while other 15 rats used for RT-PCR detection were assigned into sham operation group and spinal cord injury group.All the disposals were in agreement with the ethical standard for animals.②The spinal cord contusion model of rats was established according to Allen's falling strike method.Laminectomy was conducted without strike in the sham operation group.The quantity and morphology of NSCs,gila cells and SDNSF-positive cells were observed by immunochemistry to detect expressions of nestin,glial fibrillary acidic protein(GFAP)and SDNSF in the injured spinal cord on days 8 and 16 after injury.The expression of SDNSF mRNA in the injured spinal cord was studied by semi-quantitative RT-PCR on days 4,8,12,16 after injury. RESULTS:①There were nestin-positive cells about central canal of spinal cord in the sham operation group.The nestin-positive cells showed erupted roots,migrated peripherally and proliferation,some GFAP-positive cells emerged and the SDNSF-positive cells were observed,which were similar to neuron on morphology on day 8 after injury.The quantity of nestin-positive cells decreased obviously,there were a number of GFAP-pesitive cells and few SDNSF-positive cells were showed on day 16 after injury.②RT-PCR revealed that SDNSF mRNA expressed in normal rate,and the expression was up-regulated on day 4 after injury,peaked on day 8,and decreased to the normal level on day 16. CONCLUSION:①There are some NSCs about the central canal of spinal cord,which proliferate and soon may differentiate to gila cell after injury in normal rats.②SDNSF is expressed in the normal spinal cord.The expression of SDNSF mRNA in the spinal cord varies with injured time,accompanying the proliferation and differentiation of NSCs. There are intimate relations between NSCs and expression of SDNSF in the repair of spinal cord injury.