益生菌对非酒精性脂肪性肝病小鼠肠道菌群及STING信号通路的影响

Effects of probiotics on the intestinal flora and stimulator of interferon gene STING signal pathway in mice with non-alcoholic fatty liver

目的 探讨益生菌对高脂饮食(HFD)诱导的非酒精性脂肪性肝病(NAFLD)小鼠肠道菌群及干扰素基因刺激因子(STING)信号通路的影响。方法 将SPF级雄性C57BL/6小鼠随机分为对照组(n=20)、实验组(n=20)及治疗组(n=20),对照组小鼠给予普通饲料,实验组和治疗组小鼠给予高脂饲料。喂养12周后,治疗组小鼠给予益生菌治疗,于治疗后第1、2和4周对3组小鼠进行各指标检测。采集小鼠粪便标本检测其肠道菌群数量;应用双能X线吸收法检测小鼠全身脂肪含量;使用酶联免疫吸附剂测定法检测肝功能指标和炎症因子水平;采用RT-qPCR及Western Blot检测STING及相关炎性细胞因子的表达;采用免疫组织化学技术检测巨噬细胞标志物F4/80的表达。结果 与实验组相比,治疗组小鼠肠道菌群得到改善,双歧杆菌和乳杆菌数量升高,肠杆菌、肠球菌及白假丝酵母数量降低(均P<0.01);治疗组小鼠脂肪含量降低(P<0.01),肝功能指标谷草转氨酶、丙氨酸氨基转移酶、三酰甘油及STING表达量显著降低(均P<0.05),F4/80+在肝脏组织中的比例明显降低(P<0.01)。此外,与实验组相比,治疗组小鼠炎症因子肿瘤坏死因子-α、白介素1β、白介素6、干扰素β表达水平及磷酸化NF-κB p65水平显著降低,JNKp46水平显著升高(均P<0.05)。结论 益生菌可能通过抑制STING-TBK1-NF-κB通路改善肠道菌群,从而改善HFD诱导的NAFLD。

Objective To observe the effect of probiotics on stimulator of interferon gene(STING) signaling pathway in mice with nonalcoholic fatty liver disease(NAFLD) induced by high fat diet(HFD). Methods SPF male C57BL/6 mice were randomly divided into control group(n = 20), experiment group(n = 20) or treatment group(n = 20). After 12 weeks of continuous feeding, the treatment group was treated with probiotics, and the indicators in the three groups were tested at week 1, 2 and 4 after treatment. The feces of mice were collected and the intestinal flora content was detected. Body fat content was detected using dual-energy X-ray absorptionetry. Liver function indicators and inflammatory factor levels were detected with enzyme-linked immunosorbent assay;The expression of STING and related inflammatory cytokines were detected by using RT-qPCR and Western Blot;Macrophage marker F4/80 expression were detected using tissue immunohistochemistry. Results Compared with the experiment group, the contents of Bifidobacterium and Lactobacillus increased,while those of Enterobacter, Enterococcus and Candida albicans decreased in treatment group(all P<0.01). The fat content in the treatment group decreased(P<0.01);Liver function indexes aspartate aminotransferase, alanine aminotransferase and triglyceride significantly reduced(all P<0.05);STING expression significantly reduced, so did the proportion of F4/80+ in liver tissue(all P<0.01);The expression levels of tumor necrosis factor α, interleukin 1β, interleukin 6, interferon β and phosphorylated NF-κB p65 significantly decreased, while the JNK-p46 level significantly increased(all P<0.05). Conclusion Probiotics may improve the intestinal flora by inhibiting the STING-TBK1-NF-κB pathway,thereby improving NAFLD induced by HFD.