横向定量牵拉损伤对大鼠视网膜神经节细胞自噬水平的影响

Effect of transverse quantitative tractive injury on autophagy level of retinal ganglion cells in rats

目的:研究不同程度牵拉力对大鼠视网膜神经节细胞(RGCs)存活率和神经传导功能的影响,探讨RGCs自噬水平对上述指标的影响。方法:选取健康雄性SD大鼠30只随机分为空白组、假手术组、0.15N组、0.3N组、0.6N组,每组各6只。模型组采用横向定量牵拉法制作视神经损伤大鼠模型。空白组大鼠不予处理。假手术组仅暴露视神经,不予牵拉。造模后第1、3d行闪光视觉诱发电位(f-VEP)检查,第3d取视网膜组织行Brn-3a免疫组织化学染色观察RGCs存活情况,透射电子显微镜观察自噬小体,蛋白质印迹法检测LC3BⅡ/Ⅰ蛋白表达水平。结果:造模后第3d,与假手术组比较,模型组大鼠f-VEP P2潜伏期延长,振幅降低,视网膜组织中RGCs存活率降低,LC3BⅡ/Ⅰ蛋白表达水平降低,且各组大鼠视网膜组织中均可见自噬小体。结论:视神经牵拉伤会降低大鼠早期视网膜自噬水平,导致RGCs死亡和相应的神经传导功能障碍,且不同牵拉力造成的损伤程度不同,RGCs存活情况可能与其自噬水平有关。

AIM:To investigate the effect of different degrees of traction power on the survival rate of retinal ganglion cells(RGCs)and nerve conduction in rats,and to discuss the effect of autophagy level of RGCs on the above parameters.METHODS:A total of 30 healthy male Sprague-Dawley(SD)rats were randomly divided into empty group,sham-operation group,0.15 N,0.3 N and 0.6 N group,with 6 rats in each group.Modeling group was performed the transverse quantitative traction to make a rat model of optic nerve injury.In addition,rats in empty group were not operated and rats in sham-operation group only got optic nerve exposed.Flash visual evoked potentials(f-VEP)were performed respectively on 1 and 3 d after modeling.The survival of retinal ganglion cells was observed by Brn-3 a staining at 3 d after modeling,autophagy bodies were observed by transmission electron microscope,and the expression level of LC3 B II/I protein was detected by Western blotting.RESULTS:Compared with sham-operation group,the f-VEP P2 peak was significantly delayed and the amplitude reduced at 3 d after modeling.In addition,the survival rate of RGCs was decreased,and the expression level of LC3 B II/I protein were decreased.Autophagy bodies were observed in the retinal tissue of rats in all groups.CONCLUSION:Optic nerve traction reduced early retinal autophagy level,death of RGCs and corresponding nerve conduction dysfunction in rats,and different traction caused different degrees of injury.In addition,there was a correlation between the autophagy level and the survival of RGCs.