锌对糖尿病大鼠视网膜的保护作用

THE Experimental Study of Zinc on Protecting the Retina of Diabetic Rats

目的:观察锌对糖尿病大鼠视网膜还原型谷胱甘肽和脂质过氧化产物丙二醛含量变化以及视网膜神经细胞凋亡及凋亡相关基因表达的影响。方法:24只Wistar大鼠,随机分成3组,7周后处死,检测还原型谷胱甘肽(glutathione,GSH)、丙二醛(Maleic Dialdehyde MDA)的量以及血糖和血清胰岛素水平。TUNEL技术检测细胞凋亡情况,免疫组化SP法测定Bcl-2、Bax以及Caspase-3蛋白表达水平。结果:与正常组相比,模型组血糖值、MDA含量增高,胰岛素水平和GSH含量降低,治疗组各指标介于二者之间;模型组大鼠视网膜神经细胞凋亡数明显增多,Bcl-2阳性细胞数减少,Bax和Caspase-3蛋白表达水平增高;治疗组与模型组比较,TUNEL阳性表达减少,Bcl-2阳性细胞数增多,Bax和Caspase-3蛋白表达水平下降。结论:锌不仅可以提高糖尿病大鼠视网膜GSH含量并降低MDA水平,增强其应激能力;锌还具有抗凋亡作用。

Objective： To evaluate the changes of glutathione and maleic dialdehyde in the retina of diabetic rats. To study the expression of apoptosis and apoptosis- related genes（Bcl- 2, Bax and Caspase- 3） in the retina of diabetic rats. Metheds： twenty - four Wistar rats were randomly divided into three groups. All rats were executed after treatments for seven week. The contents of glutathione （GSH） and Maleic Dialdehyde （MDA） were detected by spectrophotometer and TBA, serum insulin was detected. Apoptosis levels were detected by TUNEL technique, the changes of Bcl - 2, Bax and Caspase - 3 were detected by immunohistochemistry. Resuits：Compared with the normal group, value of serum glucose and MDA in diabetic models were increased, plasma insulin was decreased;Streptozotocin treatment reduced GSH contents in two groups, but The combined administration of streptozotocin and zinc reversed the depleting effect on tisue GSH and reduced the elevations in MDA content. In the DM group, many Bax, Caspase - 3 and TUNEL positive cells appeared, the positive cells decreased and became weaker in zinc sulfate- treated group; Bcl- 2 expression is weaker in DM group but increased in intervension group. Conclusion：The results show the beneficial effects of Znic against oxidative stress in diabetes clearly;Zinc also could greatly reduced the amount of apoptosis ceils in the retinas of diabetic rats, which probably related inhibiting expression of Bax and Caspase - 3 and increased expression of bcl- 2.