电针对单纯性肥胖症大鼠肠道菌群-短链脂肪酸代谢轴的影响

Effect of electroacupuncture on the intestinal flora-short chain fatty acid metabolism axis in simple obesity rats

目的:观察电针对单纯性肥胖症大鼠肠道菌群-短链脂肪酸(SCFAs)代谢轴的影响,探讨电针抑制肥胖的机制。方法:22只SD大鼠随机分为对照组(6只)和模型组(16只),采用高脂饮食复制肥胖模型。将造模成功的大鼠随机分为模型组(6只)和电针组(6只)。电针组予以双侧“曲池”和“足三里”电针治疗,连续干预21 d。隔天观察大鼠体质量变化,苏木精-伊红染色观察大鼠脂肪组织和肝脏的病理变化,全自动生化分析仪检测各组大鼠血脂含量,采用16S rRNA高通量测序分析大鼠粪便肠道菌群多样性,应用超高效液相色谱-电喷雾串联质谱技术检测大鼠粪便SCFAs含量,采用Pearson法分析大鼠粪便肠道菌群相对丰度与SCFAs含量的相关性。结果:与对照组比较,模型组大鼠体质量显著升高(P<0.01),脂肪细胞直径增大,肝脏出现明显脂滴和炎性细胞浸润,血清总胆固醇(TC)和甘油三酯(TG)显著升高(P<0.01);16S rRNA测序结果显示,模型组大鼠属水平上拟杆菌属、丁酸弧菌属、罗氏菌属相对丰度显著下降(P<0.05),毛螺菌科NK4A136群组相对丰度升高(P<0.05)。与模型组比较,电针组大鼠体质量明显降低(P<0.05),脂肪细胞直径变小,肝脏脂滴和炎性细胞浸润得到改善,血清TC和TG含量显著降低(P<0.01);在门水平上拟杆菌门相对丰度显著上升(P<0.01),厚壁菌门显著下降(P<0.01),在属水平上拟杆菌属、丁酸弧菌属、罗氏菌属相对丰度显著上升(P<0.01,P<0.05);SCFAs中乙酸和丙酸含量显著升高(P<0.01)。PCoA分析显示,对照组与模型组、模型组与电针组之间的肠道菌群结构具有明显差异。在门水平上,拟杆菌门相对丰度与乙酸和丙酸含量呈显著正相关(P<0.001),厚壁菌门相对丰度与乙酸和丙酸含量呈显著负相关(P<0.001)。在属水平上,拟杆菌属、链球菌和丁酸单胞菌属相对丰度与乙酸含量呈正相关(P<0.01,P<0.05),拟杆菌属、链球菌和罗氏菌属相对丰度与丙酸含量呈正相关(P<0.001,P<0.05)。结论:电针可通过改善肠道菌群-SCFAs代谢轴失调,改善肥胖症大鼠脂质代谢紊乱,从而发挥抑制肥胖的作用。

Objective To observe the effect of electroacupuncture(EA)on the intestinal flora-short chain fatty acids(SCFAs)metabolism axis in rats with simple obesity,so as to explore the underlying mechanism of EA in reducing obesity.Methods Male SD rats were randomly divided into control group,model group and EA group,with 6 rats in each group.The obesity model was established by feeding the rats with high-fat diet.Rats in the EA group were treated with EA at“Quchi”(LI11)and“Zusanli”(ST36)for 15 min,once daily for 21 consecutive days.The changes of body weight were observed every other day.H.E.staining was used to observe the pathological changes of adipose tissue and liver.The blood lipid content was detected by automatic biochemical analyzer.The diversity of intestinal flora in rat feces was analyzed by 16S rRNA high-throughput sequencing.The content of SCFAs in rat feces was detected by ultra-high performance liquid chromatography-electrospray ionization-mass spectrometry(UPLC-ESI-(MS/MS).The correlation between the relative abundance of fecal intestinal flora and the content of SCFAs in rats was analyzed by Pearson method.Results Compared with the control group,the body weight of rats,the serum total cholesterol(TC)and triglyceride(TG)were significantly increased(P<0.01)in the model group.The results of 16S rRNA sequencing showed that,at the genus level the relative abundance of Bacteroides,Butyrivibrio and Roseburia in were decreased significantly(P<0.05),while that of the Lachnospiraceae_NK4A136_group increased(P<0.05).After the intervention,compared with the model group,the body weight,serum TC and TG contents of rats in the EA group were significantly decreased(P<0.05,P<0.01);the results of 16S rRNA sequencing showed that,the relative abundance of the Bacteroidota phylum significantly increased(P<0.01)and Firmicutes decreased(P<0.01)at the phylum level,and at the genus level the relative abundances of Bacteroides,Butyrivibrio and Roseburia significantly increased(P<0.01,P<0.05);the contents of acetic acid and propionic acid in SCFAs significantly increased(P<0.01).H.E.staining showed an increase of the diameter of adipocytes,with obvious lipid droplets and inflammatory infiltration in the model group,which was relatively milder in the EA group.PCoA analysis showed that there were significant differences in the structure of intestinal flora between the control group and the model group,as well as the model group and the EA group.At the phylum level,the relative abundance of Bacteroidota was positively correlated with acetic acid and propionic acid contents,with that of Firmicutes negatively correlated with acetic acid and propionic acid contents(P<0.001).At the genus level,the relative abundances of Bacteroides,Streptococcus and Butyricimonas were positively correlated with acetic acid content(P<0.01,P<0.05),and the relative abundances of Bacteroides,Streptococcus and Roseburia were positively correlated with propionic acid content(P<0.001,(P<0.05).Conclusion EA can improve the disorder of lipid metabolism in obese rats by improving the disorder of intestinal flora-SCFAs metabolic axis,thus playing a role in inhibiting obesity.