动脉粥样硬化模型小鼠肠道菌群及其代谢产物TMAO与心功能的相关性

Intestinal Flora and its Metabolite Trimethylamine Oxide in Correlation with Cardiac Function in Atherosclerosis Model Mice

目的探讨动脉粥样硬化模型小鼠肠道菌群特征、代谢产物氧化三甲胺(TMAO)含量、心功能水平及三者的相关性。方法10只ApoE-/-小鼠高脂饲料喂饲12周建立动脉粥样硬化模型设为模型组,另取10只C57BL/6/J小鼠作为正常组。运用小动物超声仪检测心功能[包括左心室射血分数(LVEF)、左心室短轴缩短率(LVFS)],采用全自动生化分析仪检测各组小鼠血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)含量,油红O染色观察小鼠主动脉脂质沉积情况,高效液相色谱质谱联用(LC/MS)法检测血浆TMAO水平,16SrDNA高通量测序技术分析肠道菌群特征。采用Spearman相关系数法对模型组小鼠肠道优势菌属、TMAO水平及心功能进行相关性分析。结果与正常组比较,模型组小鼠LVEF、LVFS值显著下降,血清TG、TC、LDL-C水平显著升高,HDL-C水平显著降低(P<0.05)。模型组小鼠主动脉脂质沉积明显,血浆TMAO水平明显升高(P<0.05),肠道菌群中LachnospiraceaeNK4A136group、罗氏菌属、Lachnoclostridium、肠杆菌属、优杆菌属丰度显著升高,拟普雷沃菌属丰度显著降低(P<0.05或P<0.01)。相关分析结果显示,优势菌属中Lachnoclostridium与TMAO水平呈正相关,TMAO水平与LVEF、LVFS呈正相关(P<0.05)。结论动脉粥样硬化模型小鼠肠道菌群发生紊乱,代谢产物TMAO增多,且菌群多样性改变与血浆TMAO水平及心功能具有相关性。

Objective To explore the characteristics of the intestinal flora of atherosclerosis model mice, the content of the metabolite trimethylamine oxide(TMAO), the cardiac function level, and the correlations among them. Methods Ten ApoE-/- mice were fed with high-fat diet for 12 weeks to establish the atherosclerosis model, and another 10 C57 BL/6/J mice were set as the normal group. The small animal ultrasonic detector was used to assess the cardiac function including left ventricular ejection fraction(LVEF) and left ventricular fractional shortening(LVFS);automatic biochemical analyzer was used to detect the content of serum total cholesterol(TC), triglyceride(TG), high-density lipoprotein cholesterol(HDL-C) and low-density lipoprotein cholesterol(LDL-C);Oil Red O staining was used to assess the lipid deposition of aorta;high-performance liquid chromatography-mass spectrometry(LC/MS) method was used to detect the plasma TMAO level;16 SrDNA high-throughput sequencing technology was used to analyze the characteristics of intestinal flora. The correlations among the dominant bacteria in the mice intestines, the TMAO level and the cardiac function in the model group were analyzed with Spearman correlation coefficient method. Results Compared to the normal group, the model group had significantly lower levels of LVEF and LVFS, higher levels of serum TG, TC and LDL-C, and lower HDL-C level(P<0.05). In the model group, the deposition of aorta lipid was obvious;the plasma TMAO level was significantly increased(P<0.05);the abundance of LachnospiraceaeNK4 A136group, Rosella, Lachnoclostridium, Enterobacter, and Eubacterium in the intestinal flora were significantly increased, while the abundance of Prevotella was significantly reduced(P<0.05 or P<0.01). The results of correlation analysis showed that the dominant bacteria genus Lachnoclostridium was positively correlated with the TMAO level, and the TMAO level was positively correlated with LVEF and LVFS(P<0.05). Conclusion In mice model of atherosclerosis, the intestinal flora is disturbed and the metabolite TMAO increased, suggesting that the diversity of flora changes, the plasma TMAO level and the cardiac function seem to be correlated.