过刊浏览

大鼠肾组织PETN表达下调在糖尿病肾病发展中的作用

王圆圆, 刘瑞霞, 郭兵^*, 肖瑛, 石明隽, 皮明婧, 文箐颍, 张国忠

贵阳医学院病理生理学教研室，贵阳 550004

摘要

转化生长因子-β1 (transforming growth factor-β1, TGF-β1)激活磷脂酰肌醇-3-激酶 (phosphoinositide-3-kinase, PI3K)-蛋白激酶B (protein kinase B, PKB/Akt)通路与糖尿病肾病 (diabetic nephropathy, DN)的发生发展密切相关，而第10号染色体缺失的磷酸酶和张力蛋白同源基因 (phosphatase and tensin homology deleted on chromosome ten, PTEN)可以负调节PI3K-PKB/Akt通路。本研究旨在观察糖尿病大鼠肾组织PTEN的表达变化及其在DN发生发展中的可能作用。16只Sprague-Dawley大鼠分成正常对照组和糖尿病组 (n = 8)。尾静脉注射链脲菌素 (streptozotocin, STZ)复制糖尿病大鼠模型；12周处死大鼠，检测相应生化指标并计算肾脏指数；HE染色观察肾组织病理学改变；免疫组化和Western blotting检测PTEN、TGF-β1、PI3Kp110α、Akt1、p-Akt1 (Ser473)、纤维连接蛋白(fibronectin, FN)和CollagenⅣ的蛋白表达；RT-PCR检测PTEN mRNA的表达。结果显示，糖尿病组大鼠肾脏指数、血糖、血肌酐和24 h尿蛋白较对照组显著升高 (P < 0.05)，且肾脏发生病理学改变，表明大鼠已并发DN；与对照组比较，糖尿病组大鼠肾小管上皮细胞中TGF-β1、Akt1、PI3Kp110α和肾间质FN、CollagenⅣ蛋白的表达均显著增加 (P < 0.05)；PTEN主要分布于肾小管上皮细胞中，糖尿病组大鼠PTEN蛋白的表达显著减少 (P < 0.05)，仅为对照组大鼠的49%；而p-Akt1 (Ser473)蛋白表达同总Akt1表达趋势一致，在糖尿病组大鼠表达显著增加 (P < 0.05)，且PTEN表达的减少与p-Akt1 (Ser473)表达的增多呈显著负相关 (P < 0.05)；PTEN mRNA表达在糖尿病组大鼠较对照组大鼠显著减少 (P < 0.05)。以上结果提示，糖尿病大鼠肾组织PTEN表达减少，可能使TGF-β1过激活PI3K-PKB/Akt通路，促进DN的发生发展。

关键词： 糖尿病肾病; TGF-β1; PTEN; 磷酸化Akt

分类号：R363.2+1

[Down-regulation of PTEN expression in kidney and its role in development of diabetic nephropathy in rats.] [Article in Chinese]

WANG Yuan-Yuan, LIU Rui-Xia, GUO Bing^*, XIAO Ying, SHI Ming-Jun, PI Ming-Jing, WEN Qing-Ying, ZHANG Guo-Zhong

Department of Pathophysiology, Guiyang Medical College, Guiyang 550004, China

Abstract

Transforming growth factor-β1 (TGF-β1)-activated phosphoinositide-3-kinase (PI3K)-protein kinase B (PKB/Akt) pathway is intimately related to the development of diabetic nephropathy (DN), which is negatively regulated by phosphatase and tensin homolog deleted on chromosome ten (PTEN). The present study was to investigate the expression of PTEN in the renal tissue of diabetic mellitus (DM) rats and explore its possible effect on development of DN. Sixteen Sprague-Dawley rats were divided into normal control group (n = 8) and diabetic group (n = 8) at random. Streptozotocin injection was used to establish diabetic model. After 12 weeks, the rats were sacrificed to detect relative biochemical parameters and renal index, and to observe the changes of pathomorphology by HE staining as well. In addition, immunohistochemistry staining and Western blotting were employed to detect the protein expression of PTEN, TGF-β1, PI3Kp110α, Akt1, p-Akt1 (Ser473), fibronectin (FN) and CollagenⅣ, respectively. Furthermore, the expression of PTEN mRNA was also examined by RT-PCR. The results indicated that the levels of blood glucose, serum creatinine and urine protein (24 h) were increased remarkably in the diabetic group (P < 0.05) compared with those in the control group. Compared with those in the control group, the protein expressions of TGF-β1, PI3Kp110α, Akt1 in renal tubular epithelium and the expressions of FN and CollagenⅣ in renal interstitium were increased in the diabetic group (P < 0.05). The expression of PTEN in the diabetic group was significantly reduced than that in the control group (P < 0.05), and the expression of p-Akt1 (Ser473) increased remarkably in the diabetic group which had the similar trend to Akt1 (P < 0.05). PTEN mainly located in renal tubular epithelial cells. The expression of PTEN had negative correlation to that of p-Akt1 (Ser473). Compared with that in the control group, the expression of PTEN mRNA was decreased remarkably in the diabetic group (P < 0.05). The data suggest that the down-regulation of PTEN in renal tissue of DM rats may promote the PI3K-PKB/Akt pathway over-activated by TGF-β1, which facilitates the initiation and development of DN.

Key words: diabetic nephropathy; TGF-β1; PTEN; phosphorylated Akt

收稿日期：2011-02-18　　录用日期：2011-06-01

通讯作者：郭兵　　E-mail: guobingbs@126.com

引用本文：

王圆圆, 刘瑞霞, 郭兵, 肖瑛, 石明隽, 皮明婧, 文箐颍, 张国忠. 大鼠肾组织PETN表达下调在糖尿病肾病发展中的作用[J]. 生理学报 2011; 63 (4): 325-332.

WANG Yuan-Yuan, LIU Rui-Xia, GUO Bing, XIAO Ying, SHI Ming-Jun, PI Ming-Jing, WEN Qing-Ying, ZHANG Guo-Zhong. [Down-regulation of PTEN expression in kidney and its role in development of diabetic nephropathy in rats.] [Article in Chinese]. Acta Physiol Sin 2011; 63 (4): 325-332 (in Chinese with English abstract).