hBDNF-GFP基因转染神经干细胞对视神经损伤大鼠视网膜BDNF表达的影响

目的 探讨移植hBDNF-GFP基因转染神经干细胞后对视神经损伤大鼠视网膜BDNF表达的影响.方法 ①78只SD大鼠随机分为正常对照组(n=6)、视神经夹伤组(n=72).视神经夹伤组动物行右侧视神经夹伤后随机平均分为三个亚组:分别于玻璃体腔内注射0.01 mol/L PBS(PBS组),GFP基因转染神经干细胞(GFP-NSCs组)和hBDNF-GFP基因转染神经干细胞(hBDNF-GFP-NSCs组).各组动物单纯暴露左侧视神经作为假损伤组.分别于移植后3 d,7 d,14 d和28 d处死动物取视网膜,ELISA法检测各组视网膜中BDNF含量.②另取6只视神经损伤大鼠移植hBDNF-GFP-NSCs,分别于2周、4周和8周各处死2只大鼠,取眼球做冰冻切片观察移植细胞存活、迁移情况.③35只sD大鼠随机分为4组:正常对照组(n=5)、右眼视神经损伤NSCs治疗组(n=10)、GFP-NSCs治疗组(n=10)及hBDNF-GFP-NSCs治疗组(n=10).④各组于术后4周和8周分别处死5只大鼠,West-era-blot法检测视网膜组织中BDNF表达.结果 ①ELISA结果显示,正常对照组BDNF含量与假损伤组间比较差异无统计学意义(P>0.05),移植手术后第3天时,三个损伤亚组视网膜匀浆上清中hBDNF含量明显增加(与假损伤组比较P<0.05),而三组间差异无统计学意义(P>0.05);7 d时,GFP-NSCs组与假损伤组比较差异具有统计学意义(P<0.05),而PBS组、hBDNF-GFP-NSCs组与假损伤组比较差异无统计学意义(P>0.05),PBS组与GFP-NSCs组间及hBDNF-GFP-NSCs组与GFP-NSCs组间差异具有统计学意义(P<0.05);移植第14天和28天时,PBS组和GFP-NSCs组中视网膜BDNF含量降低,而hBDNF-GFP-NSCs组中BDNF含量与其他三组比较明显升高,差异有统计学意义(P<0.05).②冰冻切片示移植后,hBDNF-GFP-NSCs可在宿主视网膜内存活,并逐渐迁移至视网膜各层.③Western-blot检测显示,各组内第4周和第8周BDNF表达差异无统计学意义,移植hBDNF-GFP-NSCs组视网膜组织中BDNF表达明显高于于其他各组.结论 hBDNF-GFP基因转染神经干细胞移植后可在宿主视网膜长期存活,且可以稳定高表达BDNF.

Effects of hBDNF-GFP gene-transfected neural stem cell transplantation on BDNF expression in the retina of rats following optic nerve crush injury

Objective To investigate the effects of human Rrain-derived neurotrophic factor-gamma fetopro-tein (hBDNF-GFP) gene-transfected neural stem cell (NSC) transplantation on BDNF expressions in the retina of rots after optic nerve (ON) crush injury. Method ①Seventy-eight Sprague-Dawley (SD) rats were randomly as-signed into a control group (n = 6) and ON crush group (n = 72). In the ON crush group, the right ON was crushed while the left NO was exposed as sham injury. Rats in the ON crush group were divided into three sub-groups: PBS group (intravitreons injection of 0.01 mol/L phosphate buffered solution); GFP group (intravitreous transplantation of GFP gene-transfected NSCs); and hBDNF-GFP group (intravitreous transplantation of hBDNF-GFP gene-transfected NSCs). Rats were sacrificed 3, 7, 14 and 28 days after transplantation, and BDNF expres-sions in retinal homogenates was detected by using enzyme-linked immunosorbent assay (ELISA). ②The hBDNF-GFP-NSCs were transplanted intravitreous into six rats after ON crush injury. Following this, two rats were sacri-riced 2, 4 and 8 weeks after transplantation. The survival and location of NSCs in host retina were observed by frozen section analysis. ③Adult SD rats were randomly divided into four groups: control group (n = 5); NSC group (NSC transplantation, n = 10); GFP-NSC group (GFP-NSC transplantation, n = 10); and hBDNF-GFP-NSC group (hBDNF-GFP-NSC transplantation, n = 10). Four and eight weeks after transplantation, five rats from every group were sacrificed. Western blot analysis was used to determine retinal BDNF expression. Results ① There was no significant difference in BDNF expression between the control group and sham-injury groups (P >0.05). Three days after NSC transplantation, BDNF expression increased significantly in the three injured sub-groups compared with the sham-injury group, (P < 0.05), whereas no significant inter-group differences in BDNF expressions among three injured sub-groups were observed (P > 0.05). Seven days after transplantation, there was a significant difference in BDNF expression between the GFP-NSC group and the sham-injury groups (P <0.05), whereas there were no significant differences in BDNF expressions among the PBS, hBDNF-GFP-NSC and sham-injury groups (P > 0.05). Fourteen and 28 days after transplantation, BDNF expressions decreased in the PBS group and the GFP-NSC groups, while BDNF expressions in the hBDNF-GFP-NSC group increased significant-ly compared with the other three groups (P < 0.05); ②Frozen section showed that transplanted hBDNF-GFP-NSCs could survive and gradually extended to all layers of the host retina. ③Westem blot revealed there were no differences in BDNF expressions between 4-week and 8-week intervals in the hBDNF-GFP-NSC group. Compared with other three groups, BDNF expressions in the retina increased significantly after hBDNF-GFP-NSC transplanta-tion. Conclusions The hBDNF-GFP gene-trausfected NSCs can survive in the host retina and BDNF expressions are stable at a high level.