Experimental Study On Survival Of The Neural Stem Cells Modified By The Gene Of Hif-1a And GDNF In The Injury Spinal Cord Rat Model After Transplantation

Objective:To investigate the survival and differentiation of the neural stem cells modified by the gene of HIF-1α and GDNF.To provide basis for the clinical application of gene therapy in the treatment of spinal cord injury.Methods:The spinal cord injury (SCI) model of Sprague-Dawley (SD) rats,weight250g±30g, were induced with modified Allen’s method by a10g×2.5cm impact on the posterior T13spinal cord. One hundred and five male SD rats were devided into five groups:(A)Normal control group,(B) injured spinal cord control group,(C)treatmented with neural stem cells modified by HIF-1αand GDNF group,(D)treatmented with neural stem cells group and, each group30rats. The HIF-1α and GDNF genetically modified NSCs labled with BrdU were transplanted into the injured spinal cord in rats model.Hind limb function of experimental rats was evaluated by a blinder observer using BBB and CSEP was observed every point24h,1w,3w,5w,8w respectively.The rats were killed according to different require after transplantation. The spinal cord were cut and the sections were processed for single or double immunochemistry staining with antibodies against BrdU,NF-200,GFAP. With light microscope the HE and immunostaining sections were observed. The immunoreactivities of BudU, NF-200, GFAP in spinal cord were measured and analyzed using LEICA QWin image processing and analysis system.Results:(1)Central core lesion was showed in H-E staining section.In NSCS+HIF-1α group the injury of hemarrage,necrosis was lighter than NSCs group and other groups,morphology was probably normal and restained cell number,Nissl body increased.(2) All the rat’s BBB score was lower at the1st day.From the7th day on,the BBB score increased gradually and to the peak at the28th day.Assessed by BBB scores,function recovery was found in groups of B,C,D and E,but it did not reach normal lever.There was significant difference between group B and group C and group D (B vs C,p<0.05;CvsD, p<0.01;).(3)CSEP in group B,C and D disappeared after injured24h,and the latency time of CSEP in groups B,Cand D,but it was shorter in group C than that in group D(p<0.01).(4)BrdU positive cells were found in the groups C and group D,and the quantity of BrdU positive cells in group C was more than in group D.(5)Cells of double labeling with anti-BrdU and GFAP,anti-BrdU and NF-200were seen in group C and group D from3rd week to8th week after transplantation,and the quantity of positive cells of double labeled in group C was more than in group D(p <0.01).Conclusion:(1)The HIF-1α and GDNF genetically modified neural stem cells can survive well in host of injured spinal cord in rats.(2) The HIF-1α and GDNF genetically modified neural stem cells not only surive well but also differentiate into neuron and astrocyte in the host of injured spinal cord of rats.(3)The ratio of differentiation of the HIF-1α and GDNF genetically modified neural stem cells was more than that no genetically modified neural stem cells.(4)Neural stem cells modified by HIF-1α and GDNF gene transplantation could improve partial recovery of motor function and conduction function of injured spinal cord in rats.(5) Neural stem cells modified by HIF-1α and GDNF could be used as one of materials to repair injured spinal cord.