【摘要】 目的 观察熊果酸（ursolic acid）补充对酒精性肝损伤的保护作用，通过粪菌移植（fecal microbiota transplantation,FMT）实验明确肠道菌群在其中的作用并探究其机制。方法 8周龄C57BL/6小鼠随机分为正常对照组、酒精模型组、熊果酸干预组，每组6只。8周造模期间，后2周每日留取各组小鼠粪便制备粪菌液。受体小鼠经肠源性细菌清除后，随机分为FMT-对照组、FMT-模型组、FMT-熊果酸组，于第7周始，每日灌胃相应粪菌液200μl，持续2周。苏木精-伊红（hematoxylin-eosin, HE）染色法观察各组小鼠肝组织病理学变化，比色法检测各组小鼠血清谷草转氨酶（aspartate aminotransferase, AST）、谷丙转氨酶(alanine aminotransferase, ALT)、总胆汁酸(total bile acid, TBA),16S r RNA基因测序分析供体小鼠肠道菌群变化，免疫印记法（western blotting, WB）检测受体小鼠肝法尼醇受体（tarnesoid X receptor, FXR）蛋白表达量。采用SPSS 22.0统计软件对实验数据进行方差分析，显著性水平（α值）设定为0.05。结果 与酒精模型组相比，熊果酸的干预能够改善酒精性肝损伤小鼠的肝脏损伤，表现为血清ALT活性降低39.3%(P<0.05)、AST活性降低16.7%(P<0.05)，同时可恢复小鼠肠道菌群的多样性。各组受体小鼠的肝脏病理学出现与供体小鼠相似的变化。对受体小鼠ALT、AST、TBA检测发现，与FMT-对照组相比，FMT-模型组小鼠的血清ALT、AST活性及TBA水平分别升高了124%、47.4%、97.5%(P<0.05);FMT-熊果酸组ALT、AST活性及TBA水平较FMT-模型组均显著降低（P<0.05）。WB结果显示，FMT-模型组小鼠肝组织中FXR蛋白表达水平低至FMT-对照组的17.8%(P<0.05)；与FMT-模型组相比，FXR-熊果酸组小鼠的肝脏FXR蛋白表达升高了2.09倍（P<0.05）。结论 熊果酸对酒精性肝损伤小鼠具有保护作用，其作用机制可能与熊果酸调节肠道菌群，调控肝FXR蛋白表达，进而维持胆汁酸稳态有关。更多还原

【Abstract】 Objective To investigate the protective effect of ursula acid(UA) supplementation on alcoholic liver injury and to clarify the role of gut microbiota through fecal microbiota transplantation(FMT) experiments, as well as to explore the underlying mechanisms. Methods Eight-week-old C57BL/6 mice were randomly divided into a normal control group, an alcohol model group, and a UA intervention group, with six mice in each group. During the 8-week modeling period, fecal samples from each group were collected daily for the last two weeks to prepare fecal microbiota solutions. After the recipient mice underwent gut-derived bacterial clearance, they were randomly assigned to FMT-control, FMT-model, and FMT-UA groups. Starting from the seventh week, each group received daily gavage of 200 μl of the corresponding fecal microbiota solution for two weeks. Hematoxylin-Eosin(HE) staining was used to observe the histopathological changes in liver tissues of the mice, and colorimetric assays were performed to measure serum levels of aspartate aminotransferase(AST), alanine aminotransferase(ALT), and total bile acid(TBA). The changes in gut microbiota of donor mice were analyzed by 16S r RNA gene sequencing, and Western blotting(WB) was used to detect the expression levels of Foresaid X receptor(FXR) protein in the liver of recipient mice. Statistical analysis was conducted using SPSS 22.0, with a significance level(α) set at 0.05.Results Compared to the alcohol model group, UA intervention improved liver injury in mice with alcoholic liver damage,evidenced by a 39.3% reduction in serum ALT activity(P < 0.05) and a 16.7% reduction in AST activity(P < 0.05), while also restoring the diversity of gut microbiota. The liver pathology of recipient mice exhibited changes similar to those of donor mice. Analysis of ALT, AST, and TBA levels in recipient mice revealed that, compared to the FMT-control group, the serum ALT, AST, and TBA levels in the FMT-model group increased by 124%, 47.4%, and 97.5%, respectively(P < 0.05); the FMT-UA group showed significant reductions in ALT, AST, and TBA levels compared to the FMT-model group(P < 0.05).WB results indicated that FXR protein expression in the liver tissue of the FMT-model group was only 17.8% of that in the FMT-control group(P < 0.05); compared to the FMT-model group, the FXR protein expression in the liver of the FXR-UA group increased by 2.09 times(P < 0.05). Conclusion UA exhibits a protective effect against alcoholic liver injury in mice,and its mechanism may be associated with the regulation of gut microbiota and the modulation of liver FXR protein expression, thereby maintaining bile acid homeostasis.更多还原