移植时间对大鼠视神经损伤后神经干细胞迁移的影响

Effects of transplantation at different time after optic nerve injury on the migration of neural stem cells in rats

目的探讨移植时间对大鼠视神经损伤后神经干细胞(NSCs)在视网膜内迁移的影响。方法 18只SD大鼠行右侧视神经损伤后按随机数字表法随机平均分为3组,并分别于损伤后当天及伤后7d和14d采用微量注射法行右眼视网膜下腔移植2μl(105个/μl)转染绿色荧光蛋白基因的NSCs(GFP-NSCs)。4周后处死大鼠,取右眼球做冰冻切片,对迁移到视网膜内的移植细胞进行计数。各组切片分别用胸腺细胞表面糖蛋白、胶质纤维酸性蛋白、β微管蛋白、视紫红质抗体进行免疫标记,观察各组移植细胞在视网膜上的分化情况。结果损伤当天及伤后7和14d移植组视网膜上的GFP阳性细胞数分别为(163441.14±16876.81)个、(145736.57±27449.07)个和(117291.33±15849.19)个,两两相较,均差异显著(P<0.01)。三组的移植细胞均可在宿主视网膜内存活、迁移,且可分化为神经胶质细胞、神经元和视网膜神经节样细胞。结论大鼠视神经损伤后随着移植时间的推迟,迁移到宿主视网膜内的移植细胞量下降。

Objective To explore the effects of transplantation of neural stem cells （NSCs） on their migration in the retinas at different time after the optic nerve （ON） injury.Methods ① Eighteen Sprague-Dawley rats with partial right ON injury were randomly divided into three groups of 6 animals each,i.e groups 1,2 and 3,where 2 μl green fluorescent protein-labeled NSCs （GFP-NSCs） containing 2×10 5 cells were transplanted into the subretinal space immediately,7 and 14 days after the injury respectively.The rats were sacrificed and their right eyeballs were removed for frozen section.GFP-NSCs migrated into host retinas were counted under fluorescence microscope.Subsequently,all the sections were prepared for the immune staining.Thy1.1,glial fibrilary acidic protein,β-tubulin Ⅲ and rhodopsin antibodies were used as markers to analyse the differentiation of the transplanted NSCs in the retinas of all the rats.Results The number of GFP-positive cells in the retinas in group 3 was significantly fewer than that in group 2 （P0.01）,in which the number of GFP-positive NSCs was significantly fewer than that in group 1 （P0.01）.The transplanted cells in three groups could survive,migrate and even differentiate into glial cells,neurons,and retinal ganglion-like cells.Conclusion The number of GFP-NSCs migrated into the retinas and survived GFP-NSCs decrease gradually as the time when the transplatation of GFP-NSCs is performed goes on after the injury in rats.