Muscle-derived IL-6 improved insulin resistance of C2C12 cells through activating AMPK and inhibiting p38MAPK signal pathway in vitro

Abstract

This paper was to probe into whether IL-6 improved insulin resistance by AMPK and p38MAPK signal pathway. The C2C12 cell lines were purchased from ATCC. The cells of control group were cultured in high-glucose DMEM culture medium. CaCl2 with different concentrations was respectively used to culture C2C12 cells; then, glucose concentrations in the nutrient solution following 24 h were measured in the preliminary experiment. Firstly, cells of A group (control group) were normally cultured C2C12 cells, cells of B, C, and D group were respectively cultured with palmitic acid 48 h, palmitic acid 24 h, and IL-6 24 h, and IL-6-shRNA 48 h, glucose concentrations, IL-6 mRNA and GLUT4 mRNA levels, p-p38MAPK, p-AMPK, p-IRS-1, and p-PI-3K protein contents of each group in the nutrient solution following 48 h were measured. Secondly, cells of A group (control group) were palmitic acid-cultured C2C12 cells, cells of B and C group were respectively cultured with palmitic acid 24 h and CaCl2 24 h, and palmitic acid 24 h CaCl2 24 h, and IL-6-shRNA 24 h, and the same indexes were measured with the first experiment. The preliminary experimental result showed that CaCl2 feed can induce C2C12 cell contraction, and CaCl2 with different concentrations was able to decrease significantly glucose concentrations in the nutrient solution following 24 h (p < 0.05). The result of the first experiment showed that, compared with B group, p-AMPK, p-IRS-1, and p-PI-3K protein contents, GLUT4 mRNA level, and glucose ingestion capacity of C group significantly increased (p < 0.05), and p-p38MAPK protein content of it significantly decreased (p < 0.05). Compared with A group, those of D group significantly decreased (p < 0.05), and p-p38MAPK protein contents of it significantly increased (p < 0.05). The result of the second experiment showed that, compared with A group, those of B group significantly increased (p < 0.05), and p-p38MAPK protein content significantly decreased (p < 0.05). Compared with B group, those of C group significantly decreased (p < 0.05), and p-p38MAPK protein contents significantly increased (p < 0.05). This experiment firstly discovered that exogenous calcium-cultured can induce contraction of C2C12 cells. Furthermore, muscle-derived IL-6 improved insulin resistance of C2C12 cells through activating AMPK and inhibiting p38MAPK signal pathway.