p38MAPK信号通路对骨骼肌胰岛素抵抗模型GLUT4表达的研究

p38MAPK signaling pathways affect the expression of GLUT4 in skeletal muscle insulin resistance model

目的通过建立棕榈酸(PA)诱导的大鼠L6肌细胞胰岛素抵抗模型,并探讨P38丝裂原活化蛋白激酶(p38MAPK)信号通路对胰岛素抵抗模型葡萄糖转运蛋白4(GLUT4)表达的影响。方法不同浓度的棕榈酸(PA)分别培养不同时间已分化的L6肌细胞,用葡萄糖氧化酶法分别检测各组培养液中剩余葡萄糖浓度,并以此判断胰岛素抵抗形成与否。L6肌细胞胰岛素抵抗模型建立后,给予不同条件干预,用Western blot方法检测胰岛素抵抗组(IR组)和吡格列酮干预组(IR+PIO组)中p-p38MAPK和GLUT4蛋白表达水平。结果通过葡萄糖氧化酶法检测培养皿上清液中葡萄糖含量发现,0.4 mmol·L-1的棕榈酸在作用24～36 h或0.6～0.8 mmol·L-1棕榈酸作用8～24 h后,其上清液中葡萄糖含量和对照组相比,明显高于对照组(P<0.05)。据此可以认为胰岛素抵抗模型建立。Western blot结果显示:和IR组相比I,R+PIO组p-p38MAPK和GLUT4水平明显增加,差异有统计学意义(P<0.05)。结论通过一定浓度和作用时间的PA的刺激可以建立大鼠L6成肌细胞胰岛素抵抗模型。p38MAPK信号通路可能是影响GLUT4表达的重要信号通路之一。吡格列酮作为PPARγ激动剂,其改善胰岛素敏感性的机制之一可能是通过激活p38MAPK信号通路。

Objective To explore the effect of p38MAPK on the expression of GLUT4 in the model of insulin resistance by establishing palmitic acid-induced insulin resistance model in rat＇s L6 muscle cells. Methods Rat L6 muscle cells were cultured in vitro and induced to differentiate into mature skeletal muscle L6 cells, which were treated with various concentration of palmitic acid. Supernatant glucose concentration in Petri dishes separated at different times was measured. Glucose Test Kit was used to detect residual glucose concentration in each group medium to observe the influence of different concentrations of PA on glucose uptake in 1.6 cells and to judge whether the insulin resistance model was established or not. According to the different conditions of intervention, pioglitazone was added to insulin resistance model by means of Western blot to test the p-p38MAPK and GULT4 expression levels respectively. Results After the use of 0.4 mmol . L- 1 palmitic acid for 24 - 36 hours or 0.6 - 0.8 mmol . L- 1 palmitic acid for 8 - 24h, the supernatant content of glucose was significantly higher than that in the NC group （ P 〈 0.05 ） , which deemed that insulin resistance model was established. The results of Western blot showed that compared with IR group, the expressions of p-p38MAPK and GULT4 in IR ＋ PIO group were increased with a significant difference （ P 〈 0.05 ）. Conclusion L6 muscle cells from rats cultured and induced by time palmitic acid stimulation with a certain concentration and a certain, can create insulin resistance model, p38MAPK signal pathway maybe is one of the important signal pathways which can affect GLUT4 expression. As the PPARY agonist, pioglitazone can improve insulin sensitivity, one of the mechanisms of which is to activate the p38MAPK signal pathway.