免疫性肝损伤大鼠肠道菌群的变化及肠黏膜屏障损伤研究*

目的: 探讨免疫性肝损伤大鼠肠道菌群及肠黏膜屏障变化。方法: 利用卡介苗(BCG)诱导建立免疫性肝损伤模型,观察大鼠肝组织的病理学改变,检测血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、二胺氧化酶(DAO)和D-乳酸(D-LA)水平,并留取粪便进行肠道菌群16S rDNA测序分析。结果: 模型组大鼠肠道菌群多样性较对照组显著升高(P＜0.05)。门水平上,两组的优势菌门均为厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes),正常对照组分别占59.50 %和37.90 %,造模组中依次占47.92 %、46.84 %,门水平肠道菌群构成差异分析,模型组厚壁菌门丰度明显降低,差异有统计学意义(P＜0.05);变形菌门(Proteobacteria)、放线菌门(Actinobacteria)与对照组相比丰度增加,差异有统计学意义(P＜0.05)。属水平肠道菌群构成差异分析,丰度较高的前20个菌属中,模型组乳酸杆菌属(Lactobacillus)、毛螺旋菌属(Lachnospiraceae)丰度均低于对照组,差异具有显著性(P＜0.05)。模型组瘤胃球菌属(Ruminococcaceae)、拟普雷沃菌属(Alloprevotella)、布劳特氏菌(Blautia)、帕拉普氏菌属(Paraprevotella)丰度均高于对照组(P＜0.05)。结论: 卡介苗所致急性肝损伤大鼠存在肠道细菌过度生长,厚壁菌门及乳酸杆菌属丰度明显下降,变形菌门、放线菌门丰度升高,存在肠道菌群结构失衡,肠道屏障受损。

Changes of intestinal flora and injury of intestinal mucosal barrier in rats with immunological liver injury

Objective: To investigate the changes of intestinal flora and injury of intestinal mucosal barrier in rats with immunological liver injury. Methods: The immune liver injury model was established with BCG induction, and the pathological changes of liver tissue of rats were observed. The levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), diamine oxidase (DAO) and D-lactic acid (D-LA) were detected, and the feces were collected for 16S rDNA sequencing analysis of intestinal flora. Results: The diversity of intestinal flora in model group was significantly higher than that in the control group (P＜ 0.05). As to the level of phyla, the dominant bacteria in the two groups both were Firmicutes and Bacteroidetes, which accounted for 59.50 % and 37.90 % in the control group respectively, and 47.92 % and 46.84 % in the model group respectively. Analysis of the difference on the composition of intestinal flora at phylum level showed that the abundance of Firmicutes in model group decreased significantly, and the difference was statistically significant (P＜ 0.05). Compared with the control group, the abundance of Proteobacteria and Actinobacteria increased in the model group, and the difference was statistically significant (P＜0.05). Analysis of the difference on composition of intestinal flora at genus level showed that the abundance of Lactobacillus and Lachnospiraceae in the model group was lower than that in the control group, and the difference was statistically significant (P＜0.05). The abundance of Ruminococcaceae, Alloprevotella, Blautia and Paraprevotella in the model group was higher than that of the control group (P＜0.05). Conclusion: There is excessive growth of intestinal bacteria in rats with acute liver injury induced by BCG, the abundance of Firmicutes and Lactobacillus decreased significantly, the abundance of Proteobacteria and Actinobacteria increased, which leads to the unbalanced structure of intestinal flora and injury of the intestinal barrier.