熊果酸对糖尿病视网膜病变小鼠视网膜损伤的保护作用

Protective effect of ursolic acid on retinal injury in diabetic retinopathy mice

目的研究熊果酸(UA)对糖尿病视网膜病变小鼠视网膜损伤的保护作用及机制。方法 C57BL/6小鼠通过腹腔注射1%链脲佐菌素(STZ) 50 mg·kg-1构建糖尿病视网膜病变小鼠模型,间隔3 d注射1次,共注射2次。从建模成功的模型小鼠中选取20只,随机分为模型组和实验组,另选取10只健康小鼠作为对照组。实验组每只小鼠玻璃体腔注射1μg·μL-1UA 3μL,模型组和对照组小鼠玻璃体腔注射等量0.9%NaCl,每日1次,连续5 d。电生理仪检测各组小鼠视觉电生理指标变化,DNA断裂的原位末端标记法(TUNEL)检测各组小鼠视网膜神经节细胞(RGCs)凋亡情况,蛋白免疫印迹法检测小鼠视网膜p38丝裂原活化蛋白激酶(p38 MAPK)信号通路蛋白表达。结果药物干预结束后,对照组,模型组和实验组小鼠a波峰潜时分别为(19.95±1.56),(24.63±1.43),(21.52±1.61) ms,a波峰振幅分别为(225.26±15.02),(206.59±12.12),(233.59±15.58) Uv;RGCs凋亡率分别为(8.76±1.67)%,(26.75±4.68)%,(17.78±2.65)%;视网膜组织中p38 MAPK蛋白相对表达量分别为0.89±0.12,1.63±0.24,1.22±0.16,Caspase-3蛋白相对表达量分别为0.68±0.14,1.24±0.13,0.66±0.10,SIRT1蛋白相对表达量分别为0.92±0.14,0.35±0.06,0.69±0.08。模型组分别与对照组和实验组比较,差异均有统计学意义(均P <0.05)。结论熊果酸减轻糖尿病视网膜病变小鼠视网膜病变程度,其机制可能与调控视网膜p38 MAPK信号通路蛋白表达相关。

Objective To investigate the protective effect and mechanism of ursolic acid(UA)on retinal injury in diabetic retinopathy mice.Methods C57BL/6 mice were given intraperitoneal injection of 50 mg·kg-1 of 1%streptozotocin(STZ)to establish diabetic retinopathy model.The diabetic retinopathy mice were injected once every 3 days,twice in total.Twenty successfully modeled mice were randomly assigned to model group and experimental group,and 10 healthy mice were assigned to control group.The experimental group received injection of 3μL of UA(1μg·μL-1)into the vitreous cavity,while the model group and the control group were injected with equal amount of 0.9%NaCl once daily for 5 days.Electrophysiology instrument was used to detect the changes of visual electrophysiological indexes,TUNEL was used to detect the apoptosis of retinal ganglion cells(RGCs)and Western blot was used to detect the expression of p38 mitogen activated protein kinase(p38 MAPK)signal pathway protein in the retina of mice.Results In the control group,the model group and the experimental group,the a wave latency were(19.95±1.56),(24.63±1.43),(21.52±1.61)ms,respectively;a wave amplitude were(225.26±15.02),(206.59±12.12),(233.59±15.58)Uv,respectively;the apoptotic rates of RGCs were(8.76±1.67)%,(26.75±4.68)%,(17.78±2.65)%,respectively;the relative expression of p38 MAPK protein in retina were 0.89±0.12,1.63±0.24,1.22±0.16,respectively;the relative expression of Caspase-3 were 0.68±0.14,1.24±0.13,0.66±0.10,respectively;the relative expression of SIRT1 were 0.92±0.14,0.35±0.06,0.69±0.08,respectively.There were statistically significant differences between the model group and the control group/test group(P<0.05).Conclusion Ursolic acid can reduce the degree of retinopathy in diabetic retinopathy mice.The mechanism may be related to the regulation of p38 MAPK signaling pathway protein expression in retina.