结缔组织生长因子介导高糖诱导肾小管 上皮细胞肥大的机制

 【目的】 研究高糖诱导肾小管上皮细胞肥大的作用途径及可能机制｡【方法】 HK-2细胞分正常对照组(培养基含葡萄糖1 g/L),等渗对照组(葡萄糖1 g/L + 甘露醇3.5 g/L)和高糖组(葡萄糖4.5 g/L)培养｡收集各组培养至24 h,48 h,96 h的细胞,检测结缔组织生长因子(CTGF)､p27kip的mRNA水平､CTGF､p27kip的蛋白水平､细胞增殖活力､细胞周期分布及细胞总蛋白含量｡另外检测各组培养30 min､1 h､24 h､48 h时的磷酸化细胞外信号调节激酶1/2(p-ERK1/2)水平｡每个检测指标设3个重复样本｡ 【结果】 高糖刺激可引起HK-2细胞的CTGF､p27kip的mRNA及蛋白表达水平显著升高,ERK1/2磷酸化激活,阻滞于G1期的细胞显著增多,细胞增殖活力受抑制,细胞肥大主要指标胞内蛋白总含量进行性增高｡ 【结论】 证实了高糖可通过上调CTGF激活ERK1/2信号转导,从转录水平上调p27kip,从而使增殖细胞阻滞于G1期诱导细胞肥大｡

Mechanism of Tubular Epithelial Hypertrophy Induced by High Glucose

Objective]To study the mechanism of tubular epithelial hypertrophy induced by high glucose.Methods]Human tubular epithelium line HK-2 cells were cultured in DMEM/F12 medium containing 1 g/L glucose(normal control group),4.5 g/L glacose(high slucose group),and 1 g/L glucose+3.5 g/L mannitol(iso-osmia control group),respectively.The cells of every group after cultured for 24 h,48 h.and 96 h were collected.The mRNA levels of CTGF and p27~(kip) were detected by real-time PCR.The protein levels of CTGF and p27~(kip) were detected by Western blot.The cellular proliferative activities were observed by MTT.The total cellular protein contents were detected by Bradford method.The cell cycle process was analyzed by flow cytometry.The cells of every group after being cultured for 30 win,1 h,24 h,and 48 h were collected.The levels of phospho-ERK1/2 were detected by Western blot.Every step was repeated for 3 times.Results]High slucose could significantly up-regulate the mRNA and protein levels of CTGF and p27~(kip),activate ERK1/2 signal conductive pathway in HK-2 cells,make more cells arrest in G1 phase,decrease cellular proliferative activities,increase total cellular protein content reflecting cellular hypertrophy.Conclusion]CTGF is an important mediator of tubular epithelial hypertrophy induced by high slucose.The mechanism is that CTGF up-regulates the p27~(kip) expression through activating ERK1/2 pathway.Up-regulated p27~(kip) lead proliferative cell to be arrested in G1 phase and cause cellular hypertrophy.