Abstract: Objective    To investigate the neuroprotective effects of transplantation of glial cell-derived trophic factor (GDNF) gene-modified neural stem cells (NSCs) on temporary cerebral ischemia in rats.    Methods    Primary neonatal rat NSCs were transfected with GDNF plasmid (GDNF/NSCs). After 7 days they were induced to differentiate, immunohistochemistry staining was used to detect the expression of MAP2+ positive cells. Rats were subjected to two-hour middle cerebral artery occlusion and reperfusion, followed by infusion of saline, NSCs or GDNF/NSCs after reperfusion respectively. All rats were sacrificed at 1, 2, 3, 5, and 7 weeks after reperfusion. Immunohistochemistry staining was performed to identify the neuronal differentiation from implanted cells and to assess glia limitans perivascularis formed by astrocyte. Luxol fast blue（LFB）staining was used to observe nerve fiber damages.    Results    MAP2+ cells from GDNF/NSCs were higher than those from NSCs in vitro. Implanted cells differentiated into MAP2+ cells, which reached the peak at 5 weeks after reperfusion. MAP2+ cells from grafted GDNF/NSCs at 3~7 weeks after reperfusion were higher than those from grafted NSCs. The glia limitans perivascularis in ischemic areas encountered varying degrees of damages in all groups, and the damages in control group at different time points were serious, while the damages in two transplantation groups were gradually repaired over time, and the repair in GDNF/NSCs group was earlier than that in NSCs group. Furthermore, the recovery of nerve fiber in GDNF/NSCs group was stronger than that in NSCs group.   Conclusions   GDNF/NSCs provide better neuroprotective effect for temporary cerebral ischemia than NSCs, which may be related to GDNF enhancing neuronal differentiation and restoration on glia limitans and nerve fibers of NSCs. 

Key words: Neural stem cells;　Gene therapy;　Glial cell line derived neurotrophic factor;　Stroke, Glia limitans