NgR/NR2B信号通路对糖尿病大鼠视网膜神经节细胞的影响

Effect of NgR/NR2B signaling pathway on retinal ganglion cell of diabetic rats

目的:探讨Nogo受体(NgR)在糖尿病视网膜病变中的作用及下游分子机制。方法:雄性SD大鼠腹腔注射链脲佐菌素诱导糖尿病模型,糖尿病大鼠玻璃体腔内注射病毒包装的NgR反义核苷酸序列(siNgR组)、阴性核苷酸序列(scRNA对照组)或空白病毒液(糖尿病组),玻璃体腔内注射空白病毒液的正常SD大鼠为正常对照组。3个月视网膜HE染色,观察视网膜神经层厚度及节细胞密度的变化,免疫荧光组化检测NgR及其下游分子N-甲基-D-天门冬氨酸2B受体(NR2B)在视网膜神经节细胞内的共存情况,Western Blot检测NgR及NR2B在视网膜内的表达。结果:与正常对照组相比糖尿病组及scRNA对照组视网膜明显变薄、神经节细胞密度降低,siNgR组无明显变化。NgR与NR2B均表达于视网膜节细胞层,二者在视网膜神经节细胞内大量共存。与正常对照组相比,糖尿病组、scRNA对照组视网膜NgR及NR2B表达均明显增加(P<0.01),而siNgR组NgR及NR2B表达均无明显变化。结论:NgR/NR2B信号通路激活可能是糖尿病大鼠RGC数量减少的重要原因之一。

Objective：To explore role of Nogo receptor（NgR） in diabetic retinopathy and to investigate the downstream molecular mechanisms of NgR.Methods：Diabetic rats were established by intraperitoneal injection of streptozotocin.Diabetic rats were intravitreally injected with virus-carried anti-NgR nucleotide（siNgR group）,scrambled nucleotide（scRNA group）,or virus without nucleotide（diabetic group）,and naive rats in control group were administered with virus without nucleotide.Three months after diabetes onset,retinal thickness and density of retinal ganglion cell（RGC）were detected by HE staining,coexistence of NgR/NR2 B was revealed by immunofluorescence histochemistry,and expression of NgR and downstream molecular NR2 B were observed by Western Blot.Results：Compared with control group,retinal thickness and RGC density were lower in diabetic and scRNA groups,but not changed in siNgR group.Both NgR and NR2 B were expressed and coexisted in retinal ganglion layer.Compared with control group,the expression of retinal NgR and NR2 B was up-regulated in diabetic group and scRNA group（P〈 0.01）,but no obvious alteration could be detected in siNgR group.Conclusion：Activation of NgR/ NR2 B signaling pathway may contribute to the loss of diabetic RGC.