中文摘要：

目的：观察终末期糖基化终产物（AGEs）对正常大鼠近端肾小管上皮细胞（NRK52E）转分化、colla-genⅠ合成及Smads信号通路的影响。方法：应用自制的AGEs（AGE—BSA）刺激NRK52E细胞，采用免疫细胞化学方法检测pmad2／3核表达情况；ELISA方法检测细胞培养上清TGF—β1的浓度；RT—PCR检测TGF—β1、Smad2、Smad3和Smad7mRNA的表达；Western印迹检测α-平滑肌肌动蛋白（SMA）、E-钙粘着糖蛋白（cadherin）和Ⅰ型胶原（collagen Ⅱ）蛋白的表达。结果iAGE—BSA刺激15min后pSmad2／3核表达明显增加，于30min（68％）和24h（76％）出现两个高峰，与刺激前及时间匹配的BSA对照组比较均有显著差异（P〈0．05）；AGE—BSA以时间依赖方式上调TGF—β1、Smad2、Smad3和Smad7 mRNA的表达；NRK52E细胞α—SMA和collagen Ⅰ蛋白表达高于对照组（P〈0．01），E—cadherin蛋白表达低于对照组（P〈0．01），细胞上清液TGF—β1的浓度高于对照组（P〈0．01）。结论：AGEs可诱导肾小管上皮细胞Smads信号通路活化，促进肾小管上皮细胞转分化和细胞外基质collagenⅠ的合成。

英文摘要：

AIM： To investigate the effects of advanced glycation end products on activation of Smad signaling pathway and collagen Ⅰ synthesis in proximal tubular epithelial cells. METHODS ： Advanced glycation end products （ AGE - BSA） were prepared by incubation of bovine serum albumin （BSA） with D - glucose. Normal rat proximal tubular epithelial （NRK52E） cells were cultured in RPMI- 1640 medium with AGE- BSA. Phosphorylation and nuclear translocation of Smad2/3 were examined by immunocytochemistry. Levels of TGF -β1 in supematant of cell culture were measured by en- zyme -linked immunosorbent assay （ELISA）. Expression of TGF- β1, Smad2, Smad3 and Smad7 mRNA were detected by RT - PCR. Expression of α - SMA , E - cadherin and collagen Ⅰ proteins were detected by Western blotting. RESULTS： AGE - BSA induced Smad2/3 phosphorylation and nuclear translocation, two peaks occured at 30 min （68% vs 16%, P 〈 0. 05） and 24 h （76% vs 16%, P 〈0. 05） compared to 0 min. The level ofTGF - β1 markedly increased in supernatant of cell culture by induced AGE - BSA at 24 h and 48 h. The expression of TGF - β1 mRNA markedly increased at 24 h, and associated with high expression of Smad2, Smad3 and Smad7 mRNA at 48 h. AGE - BSA up - regulated significantly the expression of α - SMA and collagen Ⅰ proteins, down - regulated the expression of E - cadherin protein. CONCLUSION： AGEs induces activation of Smad signaling, as well as transdifferentiation and collagen Ⅰ synthesis in proximal tubular epithelial cells. Collagen type I ; Smad mRNA