转化生长因子β1对肾小管上皮细胞转分化和细胞外基质成分的调节与阿魏酸钠的干预效果

背景：细胞外基质在肾间质的积聚是肾小管间质纤维化的主要特征。肾小管上皮细胞-肌成纤维细胞转分化在肾间质纤维化发病机制中起了重要作用。目的：从细胞水平观察阿魏酸钠对转化生长因子β1诱导的大鼠肾小管上皮细胞-肌成纤维细胞转分化及细胞外基质主要成分Ⅰ型胶原、Ⅲ型胶原和纤维粘连蛋白的影响。设计：以细胞为观察对象，随机对照实验：单位：四川大学华西医院肾脏科、材料：大鼠肾小管上皮细胞株NRK52E来源于American Type Culture Collection（ATCC），由澳大利亚Monash医学中心肾内科实验室提供，本实验所用细胞株为第36代。阿魏酸钠为白色晶体，可溶于水，纯度〉98．0％，由成都亨达药业有限公司提供，实验时终浓度分别125，250，500μmol／L。兔抗大鼠α平滑肌肌动蛋白多克隆抗体为武汉博士德产品；ELISA试剂盒为上海森雄公司产品；人重组转化生长因子β1为R＆D公司产品：DNA Engine Opdcon^TM实时荧光定量聚合酶链反应仪为MJ Research产品。方法：将体外培养的细胞株NRK52E分为5组；空白对照组：仅加入含血清的DMEM培养基；转化生长因子β1刺激组；培养液中加入终质量浓度为5ng/L的转化生长因子β1；阿魏酸钠低、中、高浓度组：培养液中加入终质量浓度为5ng／L转化生长因子β1和125，250，500μmol／L的阿魏酸钠。主要观察指标：应用相差显微镜、实时荧光定量聚合酶链反应、酶联免疫吸附法观察阿魏酸钠对转化生长因子β1诱导的NRK52E细胞转分化的作用及对细胞外基质主要成分胶原Ⅰ胶原Ⅲ和纤维粘连蛋白的影响。结果：①NRK52E细胞形态：与空白对照组相比，转化生长因子β1刺激组细胞在培养3d后，细胞株NRK52E从原有典型的铺路石样上皮细胞形态转变为长梭形类似成纤维细胞的形态。阿魏酸钠3个浓度组细胞受转化生长因子β1的刺激而出现的形态学改变得到不同程度的改善，并呈剂量依赖性。②α-平滑肌肌动蛋白mRNA表达：转化生长因子β1 5ng／L诱导6h后α-平滑肌肌动蛋白mRNA较空白对照组上升，在72h达高峰；经过不同剂量阿魏酸钠干预72h后α-平滑肌肌动蛋白mRNA显著下调并呈剂量依赖性（P〈0．05）。③细胞外基质变化；经转化生长因子β1 5ng／L诱导72h后，细胞培养上清中Ⅰ型胶原，Ⅲ型胶原和纤维粘连蛋白含量明显增加（P〈0．05）。经过不同剂量的阿魏酸钠干预后，不同程度地抑制了转化生长因子β1促Ⅰ型胶原、Ⅲ型胶原和纤维粘连蛋白增多的作用，并呈剂量依赖性（P〈0．05）。结论：转化生长因β1可以诱导大鼠肾小管上皮细胞-肌成纤维细胞转分化，刺激细胞外基质成分Ⅰ型胶原、Ⅲ型胶原和纤维粘连蛋白的升高。阿魏酸钠可剂量依赖性地抑制转化生长因子β1所导致的肾小管上皮细胞-肌成纤维细胞转分化作用。

Effect of sodium ferulate on transdifferentiation and extracellular matrix of rat renal tubular epithelial cells induced by transforming growth factor beta 1

BACKGROUND: Renal tubulointerstitial fibrosis is mainly featured as the accumulation of extracellular matrix (ECM) in renal interstitium. The tubular epithelial-myofibroblast transdifferentiation (TEMT) is important to the pathogenesy of renal tubulointerstitial fibrosis. OBJECTIVE: To examine the effects of sodium ferulate (SF) on TEMT, and ECM main components such as collagen Ⅰ, collagen Ⅲ and fibronectin, in rat renal tubular epithelial cellsinduced by transforming growth factor-beta 1 (TGF- β1)- DESIGN: Randomized and controlled experimental study based on cells. SETTING: Department of Kidney in West China Hospital of Sichuan University. MATERIALS: Rat renal tubular epithelial cells (NRK-52E) originated from American Type Culture Collection (ATCC), were offered by the laboratory of Department of Nephrology in Australian Monash Medical Center. Cell strain used in this study was cultured at the 36th passage. SF white crystal with water solubility and more than 98.0% purify, was from Chengdu Hengda Pharmaceutical Co., Ltd. Different concentrations of SF (125,250, 500μreel/L) were designed in this study. Rabbit anti-rat α-smooth muscle actin (α -SMA) was produced by Wuhan Boster Company. Enzyme-linked immunosorbent assay (ELISA) kit was the produced of Shanghai Senxiong Science and Technology Co.,Ltd. Human recombinant TGF- β1 was produced by R&D Company. DNA Engine OpticonTM real-time fluorescence quantitative polymerase chain reaction apparatus was the product of MJ Research Company. METHODS: Rat renal tubular epithelial cells (NRK-52E) cultured in vitro were divided into five groups. Control group was added with serum-contained DMEM; TGF-β1-induced group was added with TGF-β1 at final concentration of 5 ng/L; SF at different concentrations groups were added with 125, 250, 500 μ mol/L SF and TGF- β1 at final concentration of 5 ng/L,respectively. MAIN OUTCOME MEASURES: The contrast phase microscope, real-time fluorescence quantitative polymerase chain reaction and ELISA method were used to detect TEMT of NRK52E cells induced by TGF-β1 and levels of collagen Ⅰ, collagen Ⅲ and fibronectin in the supernatant. RESULTS: Morphology of NRK52E cells: Compared with control group, TGF-β1 could induce the transdifferentiation of NRK52E cells, showing fibroblast-like in morphology after 3 days, which were previously the typical road stone-like epithelial cells. In three different concentration SF groups, the morphologic transformation stimulated by TGF-β1 could be partly ameliorated in a dose-dependent manner. Expression of α-SMA mRNA: Compared with control group, 5 ng/L TGF- β1 enhanced expression of α-SMA at 6 hours, and reached a peak at 72 hours; SF depressed the expression in a dose-dependent manner at 72 hours (P < 0.05). Changes of ECM: After induced by 5 ng/L TGF- β1 for 72 hours, the levels of collagen Ⅰ, collagen Ⅲ and fibronectin in the supernatant increased significantly (P < 0.05), whereas SF decreased these levels in a dose-dependent manner (P < 0.05). CONCLUSION: TGF- β1 induces the TEMT, and promotes the secretion of collagen Ⅰ, collagen Ⅲ and fibronectin. SF can inhibit TGF- β1-induced TEMT In a dose-dependent manner.