Abstract: Objective To investigate the effects of n-3 polyunsaturated fatty acids (n-3 PUFAs) on the gut microbiota in diet-induced obese (DIO) mice. Methods Thirty 3~4-week-old male C57BL/6J mice were randomly divided into 3 groups and fed 4 months with two different high-fat diets (34.9% of fat providing 40% of total energy)- the high-fat diet (lard oil and sunflower oil) and the fish oil high-fat diet (lard oil and fish oil),and a low-fat diet (4.3% of fat from lard oil and sunflower oil,providing 10% of total energy).The stool bacteria were examined by 16s DNA real-time PCR,and the mRNA expression levels of IL-1β,IL-6,IL-10,TNF-α and MCP-1 in the colon were determined by reverse transcription real-time PCR. Results As compared to the lean mice,the obese mice induced by the high-fat diet had more Firmicutes and Lactobacillus,and less bacteroidetes,actinobacteria,proteobacteria and bifidobacterium in stool.Comparing differences between the two groups of obese mice,higher abundance of stool bifidobacterium and lower lactobacillus were found in mice with the fish oil high-fat diet.Analysis for mRNA expressions of inflammatory factors in the colon showed that IL-1β,IL-6,TNF-α and MCP-1 were all increased in the high-fat diet induced mice compared to the mice fed low-fat diet,and fish oil n-3 PUFAs reduced expressions of colon IL-1β and TNF-α. Conclusion Fish oil n-3 PUFAs may have beneficial effects on gut microbiota and related colon inflammation in DIO mice.

Key words: n-3 polyunsaturated fatty acids, obesity, intestinal inflammation, gut microbiota, mice

摘要： 目的 探讨n-3多不饱和脂肪酸(n-3 polyunsaturated fatty acids,n-3 PUFAs)对饮食诱导肥胖小鼠肠道菌群的影响。方法 将30只3～4 周龄C57BL/ 6J雄性小鼠,随机分为3组(10只/组),分别给予高脂饲料、鱼油n-3 PUFAs高脂饲料(脂肪含量均为34.9%,供能比均为60%)以及正常脂饲料(脂肪来源于猪油和葵花籽油,脂肪含量为4.3%,供能比为10%)喂养16周。然后采集粪便,采用16sDNA-实时荧光定量PCR方法检测肠道菌群变化;取结肠组织,采用实时荧光定量PCR方法检测白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、白细胞介素-10(IL-10)、肿瘤坏死因子-α(TNF-α)以及单核细胞趋化蛋白-1(monocyte chemoattractant protein-1,MCP-1)的mRNA表达水平。结果 与正常脂饲料喂养对照组小鼠相比,高脂饲料诱导肥胖小鼠粪便中厚壁菌门及乳杆菌属的数量显著增多,而拟杆菌门、放线菌门、变形菌门以及双歧杆菌属的数量则显著减少(P<0.05)。两组肥胖小鼠相比,鱼油n-3 PUFAs高脂组肥胖小鼠的粪便双歧杆菌属数量明显增加,而乳杆菌属数量显著减少(P<0.05)。对结肠炎性因子mRNA表达水平检测显示,高脂饲料组肥胖小鼠的IL-1β、IL-6、TNF-α及MCP-1表达量较正常脂饲料组小鼠均明显升高(P<0.05),而IL-10的表达量无变化;鱼油n-3 PUFAs高脂饲料组肥胖小鼠的IL-1β、TNF-α较高脂饲料组肥胖小鼠有显著性的降低(P<0.05)。结论 鱼油n-3 PUFAs可以改善肥胖状态下的肠道菌群紊乱及肠道炎症状态。

关键词: n-3多不饱和脂肪酸, 肥胖, 肠道菌群, 肠道炎症, 小鼠