N-乙酰半胱氨酸对衰老小鼠抗氧化机能和肠道菌群的影响

摘要

本研究旨在探讨N-乙酰半胱氨酸（ NAC）对衰老小鼠抗氧化机能和肠道菌群的影响。试验利用D-半乳糖诱致衰老模型小鼠，并通过饮水给小鼠服NAC，测定回肠壁组织中谷胱甘肽过氧化物酶（ GSH-Px）、过氧化氢酶（ CAT）活性及丙二醛（ MDA）含量抗氧化指标，采用变性梯度凝胶电泳（ DGGE）技术观察小鼠肠道菌群的变化，利用荧光定量PCR测定黏附相关基因表达。结果表明：NAC使衰老小鼠回肠壁组织中GSH-Px、CAT活性显著升高（P＜0．05），MDA含量显著降低（ P＜0．05）。 NAC使衰老小鼠肠道乳酸杆菌、双歧杆菌和肠球菌数量增加，大肠杆菌数量减少。 NAC使衰老小鼠回肠壁组织三叶因子3（ TFF3）、黏液素3（ MUC3）基因表达量显著升高（ P＜0．05）。因此，NAC能提高衰老小鼠抗氧化机能并通过抗氧化能力的调节来影响小鼠肠道菌群，而且NAC调节肠道菌群的机理可能与TFF3和MUC3基因表达有关。%The aim of this study was to investigate the effects of N-acetylcysteine ( NAC) on antioxidant ability and intestinal microflora in aging mice. D-galactose induced aging mice models were designed firstly. NAC containing water was provided for these mice freely. The activities of glutathione peroxidase ( GSH-Px) and catalase ( CAT) and malonaldehyde ( MDA) content were subsequently measured in the ileum tissues. Finally, changes in intestinal flora were observed by denaturing gradient gel electrophoresis ( DGGE) , and fluorescence quantitative RT-PCR was used to measure the mRNA expression of adhesion associated genes in the ileum of mice. Results showed as follows:after NAC supplementation, the activities of GSH-Px and CAT were signifi-cantly increased (P<0.05), while the content of MDA was significantly reduced in the ileum of aging mice ( P<0.05) . Compared with the NAC untreated aging mice, NAC could increase the number of Lactobacillus, Bifidobacterium, and Enterococcus and decrease the number of E. coli in intestinal tract of aging mice. After NAC treatment, the gene expressions of trefoil factor family 3 ( TFF3) and mucin 3 ( MUC3) were rapidly in-creased in the ileum of aging mice. Therefor, NAC has the potential to regulate the intestinal microflora chan-ges via the antioxidant capacity regulation. The regulation mechanism of intestinal microflora in aging mice might be associated with the gene expression changes in TFF3 and MUC3.