移植时间对大鼠视神经损伤后神经干细胞迁移的影响

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。

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

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 (P<0.01),in which the number of GFP-positive NSCs was significantly fewer than that in group 1 (P<0.01).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.