^*Corresponding author. Tel: +86-27-83657804; E-mail: liushengyuans@yahoo.com.cn

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

Wang Yao-Hui¹，Zheng Hai-Yan^1,2, Qin Na-Lin³, Yu Shang-Bin¹, Liu Sheng-Yuan^1,*

¹Department of Pathophysiology, TongJi Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; ²Department of Pathology and Pathophysiology, Medical College, Henan University of Science and Technology. Luoyang 471003, China; ³Department of Immunology, TongJi Medical College, Huazhong University of Science and Technology, Wuhan 430030, China

Abstract: 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 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 plus5.0 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 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 these actions of diazoxide are 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.

Key word: rat; potassium channels; sulphonylurea receptor; adipocyte; obesity; cell proliferation; cell differentiation

ATP敏感钾通道参与大鼠前脂肪细胞增殖和分化

王曜晖¹，郑海燕^1,2，秦娜琳³，余上斌¹，刘声远^1,*,

¹华中科技大学同济医学院病理生理学系，武汉 430030；²河南科技大学医学院病理与病理生理教研室，洛阳 471003；³华中科技大学同济医学院免疫学系，武汉 430030

摘 要：为了探讨ATP 敏感钾通道在前脂肪细胞增殖分化中作用，本实验使用逆转录实时定量PCR检测大鼠前脂肪细胞和诱导5 d获得的脂肪细胞中该通道受体部分磺脲类受体2 (sulphonylurea receptor 2, SUR2) mRNA表达；该通道阻滞剂格列本脲和激动剂二氮嗪对前脂肪细胞中SUR2 mRNA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-activated receptor-γ, PPAR-γ) mRNA表达。结果显示：前脂肪细胞及诱导5 d获得的脂肪细胞均有SUR2 mRNA表达，且后者明显高于前者；格列本脲抑制前脂肪细胞SUR2 mRNA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。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。

关键词：大鼠；钾通道；磺脲类受体；脂肪细胞；肥胖症；细胞增殖；细胞分化

中图分类号：Q45