烟酰胺在原代培养的猪前体脂肪细胞增殖分化中的作用

Effects of nicotinamide on proliferation and differentiation in primarily cultured porcine preadipocytes

为研究烟酰胺(Nicotinamide,NAM)在原代培养的猪前体脂肪细胞增殖分化中的作用,探讨其作用的分子机制,用不同浓度(0-500μmol/L)的NAM处理猪前体脂肪细胞。MTT和油红O染色及提取法检测结果表明:在不同的作用时间内,与对照组相比,100-500μmol/L的NAM均可以促进猪前体脂肪细胞的增殖分化,随着NAM浓度的增加,其对前体脂肪细胞增殖分化的促进作用逐渐上升,当浓度为300μmol/L时达到高峰,即300μmol/L NAM的促进效果最为显著(P<0.05);随后,400和500μmol/L NAM的促进作用逐渐减弱。RT-PCR法分析结果表明,Sirt1 mRNA表达显著下降(P<0.05),而其靶基因FoxO1和脂肪细胞分化标志基因PPARγ2、C/EBPα mRNA表达量明显升高(P<0.01),aP2和LPL表达也显著增加(P<0.05)。表明NAM是Sirt1的一个有效抑制剂,它可能通过抑制Sirt1的表达来促进猪前体脂肪细胞增殖和分化。

To investigate the effects of nicotinamide （NAM） on pig adipocyte proliferation and differentiation in primary culture, preadipocytes were cultured in the presence of 0, 100, 200, 300, 400 and 500μmol/L of NAM and cell growth and cellular lipid accumulation were evaluated. Cell growth was measured by methylthiazolyldiphenyl-tetrazolium bromide （MTT） method and cellular lipid content was assessed by Oil red O staining and extraction. Results showed that NAM （300μmol/L） significantly stimulated proliferation and differentiation of pig preadipocytes compared to the control group （ P 〈 0.05）. Subsequently, to investigate the underlying molecular mechanisms controlling the stimulatory effect of NAM, expression of Sirtl, FoxO1 and adipocyte genes （PPARγ2, C/EBPα, aP2 and LPL） were analyzed by semi-quantitative RT-PCR. After NAM treatment, Sirtl expression was markedly decreased, whereas expression of FoxO1 and other genes was significantly increased （ P 〈 0.05）. These results suggest that NAM is an effective inhibitor of Sirtl, which promotes proliferation and differentiation of pig preadipocytes through repressing Sirtl expression [Acta Zoologica Sinica 53 （6）： 1063- 1068, 2007].