Experimental Study Of Neural Stem Cell Transplantation For Focal Cerebral Ischemia

Purpose: We characterize the survival, migration, and differentiation of human neural stem cells which come from 8 weeks to 12 weeks embryonic brains and transplanted them into the ischemic cortex of rats three weeks after distal middle cerebral artery occlusion. To study the survival, migration and integration of the human neural stem cells transplanted into the rat's brain.Methods: By using serum-free cell culture and single cell clone technique, the neural stem cells were isolated and cultured from 8-week to 12-week human embryonic brain in condition with combination of EGF,bFGF,and B27. The cells could be expanded with mechanical method. Immunofluorescence tests were used to identify the cells marker Nestin and mature neural cells markers NSE,GFAP; After about 20-25 days, the primary cultured fetal brain neural stem cells which were labeled with BrdU were transplanted into the ischemic cortex of rats 3 weeks after distal middle cerebral artery occlusion. Four weeks later, behavioral test and ZealLonga5 method were used to evaluate the neural function deficits. Brains were removed 4 weeks after grafting. Immunofluorescence technique was used to detect BrdU and NSE , GFAP were detected by immunohistochemistry.Results: The human neural stem cells with the abilities of self-renewal and multipotency were successfully isolated and cultured from 8-week to 12-week embryonic brains.A combination of EGF, bFGF and B27 could be used to expand human neural stem cells for a long time, in order to get enough cells for transplantation. 1 week and 4 week after transplantation, BrdU-positive cells could be detected in the animal brain. The cells were observed to have migrated into the surrounding host brain. The longestdistance that was observed was 0.8mm from the graft core. Nestin downer -gulation and multipotency in vivo were observed, the main differentiated cells were astrocytes, a few NSE-positive cells were detected. During behavioral test, there was a distinctive improving observed in rats which NSC had been transplanted to.Conclusion: There are neural stem cells in human embryonic brains which are between 8 weeks and 12 weeks. Human embryonic neural stem cells can survive, migrate and integrate into host brain. Their migration and differentiation display site-specific properties, and have a limited migration and multipotency. After transplanting, there is a distinctive improving in behavioral appearance.