红细胞生成素对糖尿病大鼠肾脏保护作用的机制

Renal protection of erythropoietin and its mechanism in diabetic rats

目的观察红细胞生成素（EPO）对糖尿病大鼠的。肾脏保护作用，并探讨其发挥肾脏保护作用的可能机制。方法将实验大鼠随机分为正常对照组（NC组）、糖尿病模型组（DM组）和EPO治疗组（DE组）。药物干预8周后，处死大鼠，检测尿白蛋白排泄率（UAER）、血清肌酐（Scr）、血细胞比容（Hct）。肾组织切片行HE、PAS染色，观察大鼠肾脏病理改变。化学比色法检测肾脏丙二醛（MDA）含量、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）活性及总抗氧化能力（T—AOC）。免疫荧光及Western印迹法检测大鼠肾脏EPO受体（EPOR）的表达。免疫组织化学及Western印迹法检测大鼠肾脏NADPH氧化酶亚基（p47phox）、转化生长因子β1（TGF-β1）、纤连蛋白（FN）的表达。结果EPO可以减轻糖尿病大鼠肾脏病理及功能改变。各组大鼠肾脏均表达EPOR，但表达水平比较差异无统计学意义（P〉0．05）。与NC组相比，DM组大鼠p47phox、TGF-β1、FN蛋白表达增强（均P〈0．01）；GSH—Px、SOD活性及T-AOC下降（均P〈0．01）；MDA含量增加（P〈0．01）。与DM组相比，DE组大鼠p47phox、TGF-β1、FN蛋白表达减弱（均P〈0．05）；GSH—Px、SOD活性及T—AOC升高（均P〈0．01）；MDA含量降低（P〈0．01）。结论EPO可通过抑制糖尿病大鼠肾脏氧化应激，降低TGF—β1、FN表达，减轻糖尿病大鼠肾脏病理改变，发挥肾脏保护作用。

Objective To investigate the renoprotective effect of erythropoietin （EPO） in streptozotocin-induced diabetic rats and to explore the possible mechanism. Methods The SD rats were randomly divided into there groups： normal control rats, diabetic, diabetic treated with EPO（NC, DM, DE groups）. The rats were sacrificed after 8 weeks treatment. Renal morphology was observed by light microscopy. The expression of erythropoietin receptor （EPOR） in kidney was detected by immunofluorescence and Western blotting. The expression of p47phox, transforming growth factor （TGF） β1 and fibronectin （FN） protein in kidney was detected by immunohistochemistry and Western blotting. The activity of antioxidants including total antioxidant capacity （T-AOC）, superoxide dismutase （SOD）, glutathione peroxidase （GSH-Px） and the level of malondialdehyde （MDA） in kidney were also measured. Results EPO treatment notably attenuated renal pathologic and functional changes. The expression of EPOR was found in kidney, but there was no difference among groups （P〉0.05）. Compared with normal rats, diabetic rats showed an elevated expression of p47phox, TGF-β1, FN proteins and MDA levels in kidney as well as reduced activities of SOD, GSH-Px and T-AOC （all P〈0.01）. Compared with diabetic rats, EPO could decrease the protein expression of p47phox,TGF-β1 and FN in kidney （all P〈0.05）. Meanwhile, elevated MDA level in the kidney was decreased as well as decreased SOD, GSH-Px, T-AOC activities were significantly remitted in DE group （all P〈0.01）. Conclusion EPO can ameliorate renal damage via the inhibition of oxidative stress and TGF-β1 and FN protein expression in streptozotocin-induced diabetic rats.