低糖应激对成肌细胞增殖的影响及其机制

Effect of Low Glucose Stress on Proliferation of C2C12 Myoblast and Its Mechanism

利用小鼠骨骼肌成肌细胞系(C2C12)作为细胞模型,通过检测低糖应激对C2C12成肌细胞增殖、细胞周期分布、线粒体功能、去乙酰化酶1(sirtuin1,SIRT1)及其下游基因m RNA表达的影响,探讨低糖应激对成肌细胞增殖影响及其机制。研究发现,低糖应激(5 mmol/L)第3 d导致C2C12成肌细胞增殖下降(P<0.01)、细胞周期停滞于G0/G1期、活性氧和线粒体膜电位显著性降低;低糖应激也增加了线粒体ATP(adenosine triphosphate,ATP)合成(P<0.05),同时促进了SIRT1、FOXO3a(forkhead box O3a)、p27(p27/Kip1)m RNA表达(P<0.05)。结果表明,低糖应激可能经SIRT1/FOXO3a轴上调p27 m RNA表达,促使增殖活性下降和细胞周期停滞G0/G1。同时,低糖应激也提升了成肌细胞线粒体能量代谢的高效性。

Mouse C3H muscle myoblast （C2C12） was used as the cell model to investigate the effects of low glucose stress on myoblast proliferation and its underlying mechanism by measuring cell proliferation, cell cycle, adenosine triphosphate （ATP） level, reactive oxygen species （ROS） generation, mitochondrial membrane potential （MMP） and expression of sirtuinl （SIRT1）. C2C12 myoblasts proliferation （P〈0.01） was inhibited by low glucose stress （LG, 5 mmol/L） compared with the control group （22.5 mmol/L） on the third day. The cells were markedly arrested at the G0/G1 phase （P〈0.05）. The DCF fluorescence intensity （P〈0.05） （the quantity of ROS generation） and MMP （P〈0.05） in the C2C12 myoblasts of the LG group significantly decreased, but SIRT1, FOXO3a OCorkhead box 03a）, p27 （p27/Kipl） mRNA expression and the ATP activity in the C2C12 myoblasts of the LG group significantly increased （P〈0.05）. It could be concluded that the expression of SIRTl/FOXO3alp27 mRNA were increased by low glucose stress in C2C12 myoblast, which can contribute to the inhibition of cell proliferation and arresting in cell cycle. What＇s more, the mitochondrial energy metabolism efficiency of C2C12 myoblasts would also be enhanced by low glucose stress.