ATP敏感钾通道参与大鼠前脂肪细胞增殖和分化

为了探讨ATP敏感钾通道在前脂肪细胞增殖分化中作用,本实验用逆转录实时定量PCR方法检测大鼠前脂肪细胞和诱导5d获得的脂肪细胞中该通道磺脲类受体2（sulphonylurea receptor2,SUR2）mRNA表达,探讨该通道阻滞剂格列本脲和激动剂二氮嗪对前脂肪细胞中SUR2mRNA表达的影响;MTT检测前脂肪细胞增殖;流式细胞仪检测细胞周期;油红O染色法检测细胞内脂质含量;Image-Pro Plus5．0软件测量细胞直径;逆转录PCR检测过氧化物酶体增殖物激活受体-γ（peroxisome proliferator-activatedreceptor-γ PPAR-γ）mRNA表达。结果显示：前脂肪细胞及诱导5d获得的脂肪细胞均有SUR2mRNA表达,且后者明显高于前者;格列本脲抑制前脂肪细胞SUR2mRNA表达,剂量依赖性地促进前脂肪细胞增殖,增加G2／M＋S期细胞百分比,增加细胞脂质含量,使脂肪细胞直径增大,增加PPAR-γ mRNA的表达;二氮嗪在这些方面的作用与格列本脲相反。以上结果提示,ATP敏感钾通道在前脂肪细胞增殖和分化中可能起调节作用,PPAR-γ可能参与这些作用。

Involvement of ATP-sensitive potassium channels in proliferation and differentiation of rat preadipocytes

This paper was aimed to investigate the effects of ATP-sensitive potassium channels on the proliferation and differentiation of rat preadipocytes. We examined the expression of sulphonylurea receptor 2 (SUR2) mRNA in preadipocytes and adipocytes obtained by inducing for 5 d and the effects of the inhibitor (glibenclamide) and opener (diazoxide) of ATP-sensitive potassium channels on the expression of SUR2 mRNA in preadipocytes by real-time PCR. Preadipocyte proliferation and cell cycle were measured by MTT spectrophotometry and flow cytometer. The content of intracellular lipid was measured by oil red O staining, cell diameter was determined by Image-Pro Plus 5.0 software and the expression of peroxisome proliferator-activated receptor-γ(PPAR-γ) mRNA was estimated by RT-PCR. SUR2 mRNA was expressed in both preadipocytes and adipocytes obtained by inducing for 5 d, and the expression in adipocytes was obviously higher than that in preadipocytes. Glibenclamide inhibited the expression of SUR2 mRNA in preadipocyte, promoted preadipocyte proliferation in a dose-dependent manner, increased the cell percentages in G2/M + S phase,increased lipid content, augmented adipocyte diameter, and promoted the expression of PPAR-γ mRNA. But the actions of diazoxide were contrary to those of glibenclamide. These results suggest that ATP-sensitive potassium channels regulate the proliferation and differentiation of preadipocytes, and PPAR-γ is probably involved in the effect of ATP-sensitive potassium channels.