补充n-3多不饱和脂肪酸对高脂饮食大鼠肠道菌群及门静脉血内毒素的影响

Effect of n-3 Polyunsaturated Fatty Acids on Gut Microbiota and Endotoxin Levels in Portal Vein of Rats Fed with High-fat Diet

目的观察补充n-3多不饱和脂肪酸(n-3PUFAs)对高脂饮食大鼠肠道菌群及门静脉血内毒素水平的影响。方法将36只雄性SD大鼠随机分为普通饮食组(CD,n=10)、高脂饮食组(HFD,n=10)、普通饮食+n-3PUFAs组(CD+n-3PUFAs,n=7)、高脂饮食+n-3PUFAs组(HFD+n-3PUFAs,n=9)4组,饲养10周后,取大鼠新鲜粪便提取DNA,采用Real-time PCR方法检测肠道菌群组成,改良偶氮基质显色鲎试剂法检测门静脉血清内毒素水平。结果饲养前,各组大鼠体重差异无统计学意义(P=0.613);饲养10周后,HFD组大鼠体重明显高于CD组(P=0.0002)、CD+n-3PUFAs组(P=0.0001)和HFD+n-3PUFAs组(P=0.022)。饲养10周后,HFD组大鼠粪便中厚壁菌门(P=0.002)和肠杆菌科(P=0.022)的含量明显高于CD组大鼠,拟杆菌门(P=0.026)和双歧杆菌属(P=0.034)含量明显低于CD组。CD+n-3PUFAs组大鼠粪便中的拟杆菌门含量明显高于CD组(P=0.043)。HFD+n-3PUFAs组大鼠粪便中的厚壁菌门含量(P=0.044)和肠杆菌科含量(P=0.012)明显低于HFD组,拟杆菌门含量明显高于HFD组(P=0.042)。饲养10周后,HFD组大鼠血内毒素水平明显高于CD组(P=0.007),HFD+n-3PUFAs组明显低于HFD组(P=0.042),CD+n-3PUFAs组与CD组差异无统计学意义(P=0.210)。结论高脂饮食可增加大鼠的体重,改变其肠道菌群。补充n-3PUFAs可以部分修复这种改变,并降低门静脉血中内毒素水平,减少体重。

Objective To investigate the effect of n-3 polyunsaturated fatty acids （n-3PUFAs） on gut microbiota and endotoxin levels in portal vein of rats fed with a high-fat diet （HFD）. Methods Thirty-six male Sprague-Dawley rats were randomly divided into four groups and fed with normal control diet （ CD）, HFD, CD supplemented with n-3PUFAs, and HFD supplemented with n-3PUFAs, respectively. Fresh fecal samples were collected to analyze the gut microbiota 10 weeks after feeding. DNA was exacted from the fresh fecal samples. Quantitative PCR was used to detect the composition of the gut microbiota. The endotoxin levels were detected through modified azo chromogenic substrate limulus amebocyte lysate assay. Results The differences in body weight before breeding in each group were not statistically significant among these four groups （ P = 0. 613 ） . The increase in the body weight was significantly larger in the HFD group than in the CD group （P = 0. 0002）, CD ＋n-3PUFAs group （P =0. 0001 ）, and HFD ＋ n-3PUFAs group （P =0. 022） . There were significantly more firmicutes （ P = 0. 002） and enterobacteriales （ P = 0. 022 ） and significantly less bacteroidetes （ P = 0. 026） and bifidobactera （P =0. 034） in the gut of rats from HFD group than those from the CD group. There were significantly more bacteroidetes in the fecal samples of the rats from the CD ＋ n-3PUFAs group compared to those from the CD group （P = 0. 043 ） . There were significantly more firmicutes （P = 0. 044） and enterobacte- riales （P--0. 012） and less bacteroidetes （P =0. 042） in the fecal samples of the rats from HFD group com- pared to those from the HFD ＋ n-3PUFAs group. The endotoxin in plasma form portal vein of rats in HFD group were significantly higher than in CD group （P =0. 007） and HFD ＋ n-3PUFAs group （P =0. 042） but showed no significant difference between CD ＋ n-3PUFAs and CD group （P = 0. 210） . Conclusions HFD can in- crease body weight and change gut microbiota. Supplementation of n-3PUFAs can partially counteract such gut dysbiosis, lower endotoxin level in portal vein blood, and improve the body weight.