桑白皮颗粒通过活化Rho-GTPase触发高血糖小鼠神经元生长锥的转向效应

Trigger effect of Cortex Mori Radicis-treatment on growth cone turning of DRG neurons mediated by Rho-GTPase in hyperglycemic mice

目的 基于Rho-GTPase通路探讨桑白皮颗粒对高血糖小鼠背根神经元生长锥转向的触发效应。方法 将C57BL/6小鼠80只,随机分为4组:正常组(20只)、高血糖组(20只)、桑白皮颗粒组(20只)和格列喹酮组(20只);通过腹腔注射50 mg/kg链脲佐菌素建立小鼠高血糖模型;再用桑白皮颗粒和阳性对照药物格列喹酮,以100mg/kg剂量灌胃,1天1次,连续7天。检测小鼠血糖水平并提取背根神经节进行HE染色观察正常神经元比例和免疫组化染色观察神经元内突触素表达,并分离背根神经节神经元进行生长锥转向实验以及蛋白免疫印迹检测突触素、Cdc42、Rac和RhoA等蛋白水平。结果 与正常组比较,高血糖组小鼠血糖水平明显升高,背根神经节中神经元胞体内尼氏体明显溶解减少,突触素表达亦减少;分离的背根神经元生长锥对神经营养因子(NGF)无转向触发效应,Cdc42、Rac表达降低,RhoA表达增加。与高血糖组比较,桑白皮组小鼠血糖升高不明显;HE染色显示神经元内尼氏体形态数量未见明显变化,突触素表达明显增加;Cdc42、Rac表达增加,RhoA表达降低,生长锥对NGF有显著转向触发效应。结论 桑白皮颗粒可有效控制血糖,并通过活化Rho-GTPase途径对神经元生长锥转向有显著触发效应,预防神经元损伤。

Objective To explore trigger effect of Cortex Mori Radicis-treatment based on Rho-GTPase pathway at ST36 on growth cone turning in dorsal root ganglion neurons of hyperglycemic mice.Methods A total of 80 C57 BL/6 mice were randomly devided into four groups: normal group(20 mice),hyperglycemic group(20 mice),Cortex Mori Radicis group(20 mice) and Gliquidone group(20 mice).The mice of hyperglycemic,CMR and Gliquidone group were injected with 50 mg/kg streptozotocin to establish hyperglycemia model.Meanwhile,the mice of CMR and Gliquidone(positive control drug) group were perfused with 100 mg/kg CMR or Gliquidone once a day for 7 days.The blood glucose level was detected and the dorsal root ganglion was extracted for HE staining,and synaptophysin was observed by immunohistochemical staining.Cdc42,Rac and RhoA were detected by Western blotting,and neurons of dorsal root ganglion were isolated for growth cone turning.Results Compared with normal group,The blood glucose level in hyperglycemia group increased significantly,the Nissl bodies in the DRG neurons decreased,the expression of synaptophysin,Cdc42 and Rac decreased,but Rho increased.Acutely isolated neurons had no triggering effect on NGF growth cone turning.Compared with hyperglycemic group,change of blood glucose level in CMR group was not significant,HE staining showed that the number of Nissl bodies in neurons was not significant,expression of synaptophysin,Cdc42 and Rac significantly increased,but Rho decreased.Conclusion CMR might effectively control blood glucose and significantly trigger the growth cone turning via activating of Rho-GTPase pathway.