·糖尿病基础研究·

　　【摘要】 目的 观察瘦素(LP)对人近端肾小管上皮细胞(HK-2)转分化及与转化生长因子-β1(TGF-βl)表达的影响，探讨其诱导转分化的机制。 方法 不同浓度LP(10、50、100 ng/ml)刺激体外培养的HK-2细胞，以及LP作用不同时间(24、48、72 h)进行分组，倒置显微镜下观察细胞形态学变化;RT-PCR法和Western印迹法检测细胞α-SMA、E-cadherin、TGF-βl、FN的表达水平;ELISA法检测上清中TGF-βl蛋白表达量。抗TGF-βl抗体中和实验分析LP对HK-2细胞转分化及与TGF-βl的关系。 结果 (1)LP可使HK-2细胞逐渐由椭圆形变成长梭形，类似肌成纤维细胞的形态;(2)LP可下调E-cadherin的表达，同时上调α-SMA、TGF-βl的表达，其作用呈一定的剂量及时间依赖性;(3)抗TGF-βl抗体能够逆转LP诱导的转分化作用。 结论 LP通过诱导HK-2细胞发生转分化，参与肾间质纤维化的发生发展，其作用机制与上调TGF-βl的表达有关。

　　【关键词】 瘦素;肾小管;上皮细胞;上皮细胞-间充质转分化;转化生长因子-β1

Effect of leptin on the transdifferentiation and TGF-βl expression in human renal tubular epithelial cell line LIU Li-qiu, FU Wen, WANG Nan-nan, et al. Department of Nephrology, the Affiliated Hospital of Medical College, Qingdao University, Qingdao 266003, China

　　【Abstrust】 Objective To investigate the effect of leptin on the trans-differentiation and TGF-βl expression in human renal tubular epithelial cell line (HK-2) in vitro, and analyze the role of leptin in transdifferentiation. Methods HK-2 cells were divided into control group and leptin-treated groups (10, 50, 100 ng/ml for 48 h, respectively; 100ng/ml for 24，48，72 h, respectively. The morphological changes of cells were observed under inverted microscope. The expression of α-smooth muscle actin (α-SMA) and E-cadherin at both mRNA and protein levels were detected by real-time quantitative reverse transcription polymerase chain reaction(RT-PCR) and Western blot. The expression of TGF-βl mRNA were detected by RT-PCR, while TGF-βl secreted into the culture supernatant was determined by enzyme-linked immunosorbent assay (ELISA). Results (1) Leptin stimulated the oval-to-fusiform transdifferentiation in morphology of HK-2 cells. (2) Compared to control group, leptin-treated group showed that the expression of α-SMA was up-regulated, while the expression of E-cadherin was down-regulated. There was a obvious correlation between α-SMA and TGF-βl mRNA expression. (3) Above-mentioned effects could be inhibited by anti-TGF-βl antibody. Conclusion Leptin can promote transdifferentiation of human renal tubular epithelial cells, and plays an important role in renal interstitial fibrosis. Leptin induced epithelial mesenchymal transition may be partially related to increased TGF-βl secretion.

　　【Key words】 Leptin; Kidney tubules; Epithelial cells; Epithelial-mesenchymal transition; Transforming growth factor beta 1