| Objective:To investigate the repairable effects of transplanting the neural stem cells (NSCs)derived from the fetal brain of rats on the neural function in rats with spinal cord injury(SCI).Methods:The NSCs were isolated from fetal brain of rats(13～15 days during pregnancy),cultured and identified in vitro.The NSCs labeled by BrdU were locally transplanted into the injured spinal cord 7 days after the model rats with spinal cord injury were established.The rats with SCI were randomly divided into three groups. A group,injury group,the injury was recovered naturally after injury,B group,N.S group,10μL normal saline(N.S)was locally transplanted at 7 days after injury,C group,NSCs group,10μL NSCs suspension(approximately 1.0×10~6)was locally transplanted 7 days after injury.BBB function score,somatosensory evoked potential (SEP)and motet evoked potential(MEP)tests were performed before injury,6 days, 14 days,21 days,30 days and 60 days after injury,respectively.The model rats were killed 60 days after injury.The pathologic examination and immunohistochemical double stain were used to observe the survival,migration and differentiation of the transplanted NSCs in vivo.Results:1.The cultured cells in vitro showed positive nestin by immunofluorescence and were confirmed to be NSCs.2.BBB function score:There were not significant differences among three groups 6 days after injury(P＞0.05).Behavioral score of A group was significantly higher than those of B and C group(P＜0.05)and there were not significant differences between B and C group(P＞0.05)14 days after injury.Behavioral score in both A and C group was higher than that in B group(P＜0.05)and there were not significant differences between A and C group(P＞0.05)21 days after injury.The behavioral score in C group was the highest,in A group second and in B group was the lowest(P＜0.05)30 days after injury,as well as 60 days after injury.It was showen that the behavioral score of model rats was significantly improved in other groups.3.SEP examination:There were not significant differences among the normal SEP latent periods of three groups before injury(P＞0.05).All the SEP of three group disappeared 6 days after injury.The SEP of three groups gradually appeared,once more but the SEP latent periods were prolonged 14 days,21 days and 30 days after injury.All the SEP of three groups appeared 60 days after injury and the SEP latent periods both A and B group were prolonger than C group(P＜0.05). There were no significant differences between A and B group(P＞0.05).The SEP latent period of each group was prolonged compaired with each group before injury respectively(P＜0.05).4.MEP examination:Before injury the normal MEP latent periods of three groups did not have significant difference(P＞0.05).All the MEP of three group disappeared 6 days after injury.The MEP Of three groups gradually appeared,but the latent periods of the MEP were prolonged 14 days,21 days and 30 days after injury.All the MEP of three groups appeared 60 days after injury and the latent period in B group was the longest,in A group second,in C group the shortest, respectively(P＜0.05).The MEP latent period of A.B and C group was prolonged in compairson with each group before injury,respectively(P＜0.05).It was shown that the neural conductive functions of NSCs group was better than the other group.5.Pathology and immunohistochemical double stain:BrdU-positive cells could be detected in the spinal cord of rats in C group.It was shown that NSCs could survive in vivo.BrdU-positive cells could be noted in 1.5cm distance from the injured centre of spinal cord.It was exhibated that NSCs could migrate in vivo. BrdU+NSE and BrdU+GFAP double-positive cells could be observed in the injured spinal cord of rats in C group.It was suggested that NSCs could differentiate into neurons and astrocytes in vivo.Conclusion:The NSCs derived from the brain of the rats can be isolated,cultured and reproduced in vitro.The NSCs transplanted into the injured spinal cord injury of rats can survive,migrate and differentiate into neurons and astrocytes.The treatment with transplanting NSCs for rats with SCI can markly promote the recovery of neural function and improve the recovery of behavioral score and neural electrophysiology.
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