Ghrelin改善骨骼肌细胞胰岛素抵抗的机制研究  

The mechanism of improving insulin resistance of skeletal muscles by ghrelin

作　　者：王勇[1] 白洁[1] 匡立润[1] 刘金钢[1] 

机构地区：[1]中国医科大学附属盛京医院普通外科,110004

出　　处：《中华内分泌外科杂志》2013年第6期441-446,共6页Chinese Journal of Endocrine Surgery

基　　金：基金项目：国家自然科学基金（81000158）

摘　　要：目的观察酰化ghrelin和非酰化ghrelin分别对胰岛素抵抗（insulinresistance，IR）骨骼肌细胞的胰岛素受体后信号通路关键因子P13Kp85α、Akt／PKB及GLUT4的影响。方法大鼠L6成肌细胞经棕榈酸诱导分化，建立IR模型成功后入选实验，分为酰化ghrelin组（AG组）、非酰化ghrelin组（UAG组）、P13K抑制剂（LY）＋酰化ghrelin组（LY＋AG组）、LY＋非酰化ghrelin组（LY＋UAG组）和对照组（IR—CO组）。各组经处理因素干预24h后，激光共聚焦和流式细胞术检测各组骨骼肌细胞在胰岛素刺激下对荧光葡萄糖的摄取能力，免疫印迹法检测骨骼肌组织的磷酸化／总P13Kp85α、磷酸化／总Akt、细胞膜／总GLUT4的蛋白表达，实时荧光定量PCR法检测骨骼肌组织P13Kp85α、Akt、GLUT4mRNA的表达。结果L6成肌细胞诱导分化及IR模型建立成功；AG组和UAG组的细胞在胰岛素刺激下的葡萄糖摄取分别是IR—CO组的1．25和1．28倍，磷酸形总P13Kp85α相对蛋白表达量分别是IR-CO组的1．78和1．89倍，磷酸化／总Akt、细胞膜／总GLUT4的蛋白表达是IR—CO组的1．84和1．80倍，细胞P13Kp85α、Akt／PKB、GLUT4的mRNA表达均较对照组显著升高，LY＋AG组和LY＋UAG组细胞的上述指标较单独使用酰化ghrelin或非酰化ghrelin作用时显著下降。结论酰化ghrelin和非酰化ghrelin均能改善骨骼肌细胞的IR，增加骨骼肌细胞在胰岛素刺激下的葡萄糖摄取；能够上调骨骼肌细胞的磷酸化P13Kp85α、磷酸化Akt／PKB、细胞膜GLUT4的相对蛋白表达和3者的mRNA表达，PI3K抑制剂LY294002能够抑制酰化和非酰化ghrelin的上述改善作用。Objective To investigate the effects of acyl and deacyl ghrelin on the expressions of PI3Kp85α, Akt/PKB and GLUT4, the key factors in insulin receptor signaling pathway of insulin resistance in skeletal muscle cells. Methods Insulin resistance models were made by palmitic acid induced rat L6 myoblasts. Successful models were divided into acyl ghrelin group, deacyl ghrelin group, PI3K inhibitor（LY） ＋ acyl ghrelin group, LY ＋ deacyl gbrelin group and control group with corresponding interventions for 24h. The glucose uptake of all group was measured through laser confocal microscopy and flow cytometry. Expressions of phosphorated/total PI3Kp85α, phosphorated/total Akt and cell membrane/total GLUT4 of skeletal muscle cells were measured by Western blot, and PI3Kp85α, Akt, GLUT4 mRNA expression were detected by real-time PCR. Results Induced L6 myoblasts differentiation and insulin resistance model were successfully established. Acyl and deacyl ghrelin could increase glucose uptake for 1.25 and 1.28 folds compared to control group, and the phosphorated and total PI3Kp85α expressions were 1.78 and 1.89 folds to control group, and phosphorylated/total Akt and cell membrane/total GLUT4 were 1.84 and 1.80 folds to control group. The PI3Kp85α, Akt/PKB and GLUT4 mRNA expression were also upregulated compared to control group. The above indexes of LY ＋ acyl or deacyl ghrelin group decreased significantly compared to acyl and deacyl ghrelin group without LY. Conclusions Acyl and deaeyl ghrelin can both improve insulin resistance in skeletal muscle cells, increasing the glucose uptake under insulin-stimulation, and up-regulated the phosphorated PI3Kp85α, phosphorated Akt/PKB, and cell membrane GLUT4 relative protein expressions and mRNA expressions. PI3K inhibitor, LY294002, can inhibit the above improvement effect of acyl and decyl ghrelin.

关 键 词：骨骼肌胰岛素抵抗 GHRELIN P13 K—Akt PKB通路 

分 类 号：R587.1[医药卫生—内分泌]