Objectives: To investigate the therapeutic mechanism of Wendan Decoction for phlegm syndrome in rats with metabolic syndrome (MS).
Methods: Forty Wistar rats were randomly divided into normal control group (n=8) and 3 phlegm syndrome model groups (induced by high-fat, high-sugar, and high-salt feeding and a single-dose intraperitoneal STZ injection; n=24) treated with daily gavage of saline, Wendan Decoction (3.6 g/kg), or metformin (0.1 g/kg) for 4 weeks. General conditions and glucose and lipid metabolism parameters of the rats were monitored, and serum LPS, liver histopathology, hepatic expressions of FXR, CYP7A1 and FGFR4 and ileal expressions of FXR and FGF15 were examined. Gut microbiota structure was analyzed using 16S rDNA sequencing, and serum bile acids were quantified with UHPLC-MS/MS.
Results: The rat models of phlegm syndrome exhibited severe hepatic steatosis and necrosis, increased body weight, abdominal circumference, Lee's index, FBG, FINS, HOMA-IR, TG, TC, LDL and LPS, and decreased HDL level. The abundance of Bacteroidetes, Megamonas, and Bacteroides in gut microbiota increased while Firmicutes, Lachnospiraceae_NK4A136_group, isohyodeoxycholic acid, and glycohyodeoxycholic acid decreased significantly; hepatic FXR and FGFR4 expressions and ileal FXR and FGF15 expressions decreased while hepatic CYP7A1 expression increased significantly in the rat models. Treatment with Wendan Decoction effectively alleviated hepatic pathology, reduced body weight and abdominal circumference, improved glucose and lipid metabolic profiles and gut microbiota structure, and reversed the changes in hepatic and ileal protein expressions. Correlation analysis revealed that Firmicutes and Lachnospiraceae_NK4A136_group were positively correlated while Bacteroidetes, Megamonas and Bacteroides were negative correlated with the levels of isohyodeoxycholic acid and hyodeoxycholic acid.
Conclusions: Wendan Decoction can significantly improve metabolic profiles in rats with phlegm syndrome of MS possibly by regulating the intestinal flora-bile acid axis to modulate the intestinal flora structure and maintain bile acid homeostasis via the FXR signaling pathway.
目的: 基于肠道菌群-胆汁酸轴探讨温胆汤对代谢综合征（MS）痰证大鼠的影响。方法: 将40只Wistar大鼠随机分为正常组（n=8）和造模组（n=32），采用高脂高糖高盐饮食联合低剂量腹腔注射链脲佐菌素诱导MS痰证大鼠模型。根据模型评价标准筛选成模大鼠，将成模大鼠随机分为模型组、温胆汤组（3.6 g·kg-1·d-1）、二甲双胍组（0.1 g·kg-1·d-1），分别给予相应药物干预4周。动态记录大鼠一般情况、甘油三酯（TG）、总胆固醇（TC）、高密度脂蛋白（HDL）、低密度脂蛋白（LDL）、空腹血糖（FBG）、血清胰岛素（FINS）等指标，计算Lee's指数和HOMA-IR。ELSIA检测血清脂多糖水平，HE染色观察肝脏组织病理学改变，Western blotting检测肝脏中FXR、CYP7A1、FGFR4及回肠中FXR、FGF15蛋白表达。16S rDNA测序技术分析盲肠内容物肠道菌群结构，超高液相色谱串联质谱法（UHPLC-MS/MS）测定血清胆汁酸含量。结果: 与正常组相比，模型组大鼠肝细胞出现严重脂肪变性、坏死；体质量、腹围、Lee's指数、FBG、FINS、HOMA-IR、TG、TC、LDL、脂多糖等含量升高（P<0.05），HDL降低（P<0.05）；拟杆菌门、巨单胞菌属、拟杆菌属相对丰度升高（P<0.05）；厚壁菌门丰度、Lachnospiraceae_NK4A136_group、异猪去氧胆酸、甘氨猪脱氧胆酸等降低（P<0.05）；肝组织FXR、FGFR4及回肠组织FXR、FGF15蛋白表达降低（P<0.05），肝脏CYP7A1蛋白表达升高（P<0.05）。与模型组相比，温胆汤治疗后肝组织病理改变明显减轻；体质量、腹围、Lee's指数、FBG、FINS、HOMA-IR、TG、TC、LDL、脂多糖等含量降低（P<0.05），HDL含量升高（P<0.05）；拟杆菌门、拟杆菌属相对丰度降低（P<0.05）；Lachnospiraceae_NK4A136_group、厚壁菌门相对丰度及异猪去氧胆酸、甘氨猪脱氧胆酸等含量升高（P<0.05）；肝组织FXR、FGFR4及回肠组织FXR、FGF15蛋白表达升高（P<0.05），肝脏CYP7A1蛋白表达降低（P<0.05）；相关性分析显示厚壁菌门、Lachnospiraceae_NK4A136_group与异猪去氧胆酸、猪脱氧胆酸含量呈正相关（P<0.01），拟杆菌门、巨单胞菌属、拟杆菌属与异猪去氧胆酸、猪脱氧胆酸含量呈负相关（P<0.05）。结论: 温胆汤能显著改善MS痰证大鼠的代谢表征，其作用机制或与调节肠道菌群-胆汁酸轴功能密切相关，可能通过介导FXR信号通路，调整MS痰证大鼠肠道菌群结构，维持胆汁酸稳态，从而改善MS痰证。.
Keywords: Wendan Decoction; bile acid; intestinal flora; metabolic phenotype; metabolic syndrome; phlegm syndrome.