熊胆粉对2型糖尿病小鼠胆汁酸-肠道菌群轴的影响

Effects of bear bile powder on bile acids and intestinal flora in type 2 diabetic mice

关键词:  熊胆粉  2型糖尿病  胆汁酸  肠道菌群

Key words:  bear bile powder  type 2 diabetes  bile acid  intestinal flora

摘要:

[目的] 探讨熊胆粉对2型糖尿病（T2D）小鼠的胆汁酸含量及肠道菌群的影响。[方法] 通过高脂饮食联合腹腔注射链脲佐菌素诱导建立T2D小鼠模型。小鼠分为正常对照组、高脂饮食组、模型组、二甲双胍组、熊胆粉组，给药8周，每日1次。给药结束后，检测小鼠的糖代谢、脂质代谢、肝功能酶、血清空腹胰岛素（FINS）和脂多糖结合蛋白（LBP）水平；计算胰岛素抵抗指数（HOMA-IR）；基于超高效液相色谱-串联质谱检测分析小鼠肝脏组织中胆汁酸含量；16S rRNA基因扩增子测序法检测小鼠粪便中肠道菌群的结构变化；采用斯皮尔曼相关性分析进行糖代谢指标、胆汁酸与肠道菌群的相关性分析。[结果] 与模型组相比，熊胆粉预防性给药后，能显著降低T2D小鼠空腹血糖（FBG）、口服葡萄糖耐量试验曲线下面积（OGTT AUC）、FINS、HOMA-IR、总胆固醇及低密度脂蛋白胆固醇水平，显著升高肝脏中脱氢石胆酸、23-脱甲脱氧胆酸、猪胆酸和牛磺石胆酸-3-硫酸盐含量（P＜0.05）。熊胆粉还可以显著降低小鼠肠道菌群丰富度、多样性指数和血清LBP含量，增加乳球菌属、嗜黏蛋白阿克曼菌属和乳杆菌属的相对丰度。斯皮尔曼相关性分析发现乳杆菌属不仅和23-脱甲脱氧胆酸呈正相关，而且与OGTT AUC、FINS和HOMA-IR呈负相关。HOMA-IR与嗜黏蛋白阿克曼菌属负相关。[结论] 熊胆粉可以改善T2D小鼠的糖脂代谢水平，调节胆汁酸水平并重塑肠道菌群。

Abstract:

[Objective] To investigate the effects of bear bile powder（BBP） on bile acid content and intestinal flora in mice with type 2 diabetes（T2D）. [Methods] In order to create T2D model mice，high-fat diets combined with an injection of streptozotocin（STZ） were used. The mice were then divided into five groups：normal control，high-fat diet，model，metformin，and BBP. The drug was given once daily for 8 weeks. Following gavage，mice were assessed for glucose metabolism level，lipid metabolism，liver function enzymes，serum fasting insulin，and lipopolysaccharide binding protein；the homeostasis model assessment-insulin resistance（HOMA-IR） index was computed；bile acid content in liver tissue was determined using UPLC-MS/MS；structural changes in mouse feces were detected using 16S rRNA gene amplicon sequencing；and the relationship between bile acid and intestinal flora was examined using Spearman correlation analysis. [Results] Prophylactic BBP administration resulted in significant reductions in the levels of fasting blood glucose（FBG），oral glucose tolerance test area under the curve（OGTT AUC），fasting insulin（FINS），HOMA-IR，total cholesterol（TC），and low-density lipoprotein cholesterol（LDL-C） when compared to the model group. Additionally，the liver’s content of dehydrohydrocholic acid，23-deoxycholic acid，porcine cholic acid，and taurocholic acid-3-sulfate was significantly increased（P＜0.05）. The relative abundances of Lactococcus，Akkermansia，and Lactobacillus were all raised by bear bile powder，whereas the richness indexes，diversity indexes，and serum LBP were considerably lowered. Spearman Correlation analysis revealed that Lactobacillus was shown to be negatively correlated with OGTT AUC，FINS，and HOMA-IR in addition to being favorably correlated with 23-demethodeoxycholic acid. Akkermansia has a negative correlation with HOMA-IR. [Conclusion] In T2D mice，BBP enhanced the metabolism of fats and carbohydrates，altered the intestinal flora，and controlled bile acid levels.