腺苷甲硫氨酸对成肌细胞成脂分化及脂肪沉积的影响

 【目的】以小鼠成肌细胞（C2C12）为模型探讨蛋氨酸代谢产物腺苷甲硫氨酸（S-adenosylmethionine，SAM）对肌肉来源的多能干细胞成脂分化及脂肪沉积的影响。【方法】分别用含有0、0.25、1.0和2.0 mmol?L-1 SAM的培养基处理细胞，在处理后的0、24、36和48 h分别对各处理组细胞进行油红O染色观察细胞形态并测定光密度（OD）值；在处理后第2天收集细胞总RNA与总蛋白，分别用RT-PCR和western blotting方法检测细胞成脂相关基因的mRNA与蛋白表达水平。【结果】经SAM处理后，细胞表现出脂肪细胞的形态特征；细胞内脂肪沉积水平上升，并且随SAM处理浓度的升高呈现出剂量依赖效应；细胞的脂肪特异性基因PPARγ、C/EBPα的mRNA及蛋白表达水平显著升高（P＜0.05）；其它特异性基因aP2、FAS及SREBP-1的表达在经SAM处理后呈剂量依赖性升高（P＜0.05），其中2.0 mmol?L-1 SAM处理组升高最为显著，三者mRNA表达水平分别上升了6.86（P＜0.01）、3.45（P＜0.05）和3.48（P＜0.01）倍。【结论】SAM可以促进C2C12细胞成脂分化及细胞内脂肪的沉积。

Effects of S-Adenosylmethionine(SAM) on Adipogenic Differentiation and Lipid Accumulation of C2C12 Cells

【Objective】This experiment was conducted to investigate the effects of S-adenosylmethionine (SAM) on adipogenesis and lipogenesis of C2C12 mouse myoblast. 【Method】Cells were cultured in high glucose DMEM medium containing 0 mmol?L-1, 0.25 mmol?L-1, 1.0 mmol?L-1, and 2.0 mmol?L-1 SAM. After treated for 0 h, 24 h, 36 h, and 48 h, cells were stained with Red Oil O and observed under microscope. The lipid accumulation in cytosol was determined by optical density (OD) measurement. After being treated for 2 d, cells were harvested for collection of total RNA and protein. Then RT-PCR and western blotting approaches were used to determine mRNA and protein expression levels of several genes related with adipogenesis and lipogenesis. 【Result】The results showed that, compared with the control group, C2C12 cells presented typical features of adipocytes when observed under microscope after treated with SAM. SAM also increased the number of lipid droplets in the cells. In addition, the increasing trend became more significant when cells were treated with higher concentration of SAM. At the same time, mRNA and protein expression levels of key regulator of differentiation of adipocytes, PPARγ and C/EBPα, were elevated (P＜0.05) after treatment. mRNA expression levels of other lipogenesis related genes, such as aP2, FAS and SREBP-1, were also elevated markedly. Compared with the control group, the relative mRNA levels of these three genes were increased by 6.86 (P＜0.01), 3.45 (P＜0.05), and 3.48 (P＜0.01) folds, respectively, in 2.0 mmol?L-1 group. 【Conclusion】The results indicated that SAM had the ability to promote adipogenic differentiation and lipid accumulation of C2C12 cells.