巨噬细胞条件培养基对胰岛素调节骨骼肌细胞作用的影响

The Effect of the Macrophage Conditioned Medium on Insulin Function of Skeletal Muscle Cells

目的:探讨常氧和缺氧培养的巨噬细胞条件培养基对胰岛素调节骨骼肌葡萄糖转运子4(GLUT4)作用的影响。方法:常氧和缺氧培养巨噬细胞,提取条件培养基孵育C2C12GLUT4myc骨骼肌细胞,用偶联抗体的吸光度法测定细胞膜上GLUT4myc的含量,Real-timePCR法测定巨噬细胞TNF-αmRNA的表达,ELISA法测定巨噬细胞条件培基中TNF-α的含量。结果:常氧和缺氧培养的巨噬细胞条件培养基削弱胰岛素刺激的骨骼肌细胞GLUT4myc转位(P<0.01),但两种条件培养基对骨骼肌中胰岛素作用的影响差异无统计学意义;缺氧培养的巨噬细胞TNF-αmRNA和蛋白表达均高于常氧培养的巨噬细胞(P<0.05或P<0.01)。结论:常氧培养和缺氧培养的巨噬细胞条件培养基均直接造成骨骼肌细胞胰岛素抵抗,缺氧的巨噬细胞条件培养基并不能加重骨骼肌胰岛素抵抗。

Objective： To explore the effects of the conditioned medium （CM） from normoxia-treated and hypoxia-treated macrophages on insulin-regulated glucose transporter 4 （GLUT4） in skeletal muscle cells.Methods： The macrophages were cultured under normoxia or hypoxia condition,respectively.The CM was collected and used to incubate C2C12GLUT4myc skeletal muscle cells.The levels of GLUT4myc on the cell surface were measured by an antibody-coupled absorbance assay.The mRNA expression of TNF-α in macrophages was determined by real-time PCR.The levels of TNF-α in the media of macrophages were determined by ELISA.Results： The increase of insulin-stimulated GLUT4myc translocation was impaired under incubation with CM from both normoxia- and hypoxia-treated macrophages （P 〈 0.01）.But there was no difference in the insulin function of skeletal muscle cells between two CMs.Both mRNA and protein expression of TNF-α were higher in CM of hypoxia-treated macrophages than those of normoxia-treated ones （P 〈 0.05 or P 〈 0.01）.Conclusion： The conditioned medium from both normoxia- and hypoxia-treated macrophages directly induced insulin resistance in skeletal muscle cells.There was no direct influence in aggravation of insulin resistance in CM of hypoxia-treated macrophages.