高糖、茶多酚对人系膜细胞结缔组织生长因子、纤维连接蛋白mRNA表达的影响

Effects of high glucose, tea polyphenols on mRNA expressions of connective tissue growthfactor, fibronectin in human mesangial cells

目的:研究高糖条件下系膜细胞氧化失衡与结缔组织生长因子(CTGF)、纤维连接蛋白(FN)mRNA表达之间的关系,通过抗氧化剂茶多酚证实氧化应激在糖尿病肾硬化发展中的作用。方法:高糖(35mmol/LD鄄糖)条件下培养系膜细胞,加或不加茶多酚(20μg/ml),采用分光光度法检测不同时间点(0、12、24、36、48h)的上清液中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性、丙二醛(MDA)含量及RT鄄PCR法细胞CTGF、FNmRNA的表达水平。结果:高糖显著降低上清SOD、CAT活力(P<0.05),升高MDA水平(P<0.05),刺激系膜细胞CTGF、FNmRNA高表达;茶多酚能有效抑制高糖的上述作用(P<0.05)。结论:①高糖条件下活性氧生成增多,抗氧化酶活性下降,氧化失衡,促进组织纤维化的进展。②茶多酚通过调节氧化失衡抑制纤维化的进展。③氧化平衡失调在DN发生、发展中具有重要的作用。

Objective: To explore the effects of high glucose, tea polyphenols(TPs) on CTGF and FN mRNA expressions in cultured human mesangial cells. Methods: The study was performed with cultured human mesangial cells and the cells were cultured in high glucose medium with or without TPs. The supernatants were collected at different time points(0,12,24,36,48 h) and the activities of SOD, CAT and the level of MDA were detected by spectrophotometry. The mRNA expressions of CTGF and FN in the cells were measured by using Semi-Quantitative Reverse Transcription PCR(RT-PCR). Results: The activities of SOD and CAT in the supernatant of high glucose without TPs were markedly lower(P < 0.05) and the level of MDA greatly higher(P < 0.05), and the up-regulations of CTGF and FN mRNA in the cells were observed(P < 0.05). TPs could effectively restrain the effections of high glucose(P < 0.05). Conclusion:① Redundant oxygen free radicals are produced and the activities of anti-oxidative enzymes are inhibited when mesangial cells are cultivated in high glucose. The unbalance of oxidantion/antioxidantion might promote the expression of profibrosis factor CTGF and contribute to tissue sclerosis. ② TPs inhibit the mRNA expression of CTGF and FN by decreasing the production of superoxide and enhancing the anti-oxidative capacity of mesangial cells. ③ Oxidative stress may play an important role in the development of Diabetic Nephropathy.