[Intestinal flora polymorphisms with different lesional stages in an animal model of MAFLD].

Objective: To study the intestinal flora specific differences with different lesional stages of metabolic (disorder) associated fatty liver disease (MAFLD), namely simple steatosis and steatohepatitis, so as to provide a new direction for MAFLD-related intestinal flora transplantation and targeted therapy. Methods: Mice were fed with normal diet, methionine-choline deficient diet (MCD) and a high-fat high-fructose diet (HFHF) for 12 weeks to construct simple steatosis and steatohepatitis models. HE and Sirius scarlet staining was performed to observe the liver pathological changes. The qPCR method was used to evaluate inflammation and liver fibrosis factors. A fully automatic biochemical analyzer was used to detect changes in liver transaminase and blood lipids. 16S rRNA sequencing method was used to observe the intestinal flora differences in the feces of each group of mice. The comparison of means between two groups was performed by t-test, and the comparison of means between multiple groups was performed by one-way analysis of variance. Kruskal-Wallis rank sum test was used for non-normally distributed data. Results: NAFLD scores were determined with pathological sections (HE and Sirius scarlet staining) of mice liver, which showed that the inflammation and liver fibrosis scores of the MCD and HFHF groups were 2.12 ± 0.18 and 1.06 ± 0.24, and 2.22 ± 0.16 and 0.46 ± 0.10, respectively. The degree of liver inflammation and fibrosis was significantly higher in the MCD than the HFHF group (P < 0.001 and P < 0.01). Lipid deposition was higher in the HFHF than the MCD group (P < 0.001), and the scores were 2.36 ± 0.17 and 1.60 ± 0.24 respectively. Simultaneously, the inflammatory [tumor necrosis factor-A (TNF-a), chemokine factor-2 (CXCL-2)] and hepatic fibrosis indicators [vascular smooth muscle actin alpha (a-SMA) and connective tissue growth factor (CTGF)] had confirmed the above-mentioned results at the transcription level. Moreover, the intestinal flora diversity was reduced (P < 0.05) in the MCD group than the HFHF group, and the Simpson and Shannon index were 0.31 ± 0.10 and 0.42 ± 0.05, and 2.03 ± 0.33 and 1.70 ± 0.28, respectively, and the differences were significant between different intestinal flora groups. The levels of Desulfovibrio, Odoribacter, and Roseburia flora were significantly increased in the HFHF than the MCD group, and the levels of Faecalibaculum, Parasutterella, Alipis, Butyricimonas_virosa, Turicibacter_sp, and Romboutsia_ilealis were significantly increased in the MCD than the HFHF group, and the difference was statistically significant (P < 0.05). Conclusion: There are significant differences in intestinal flora diversity between simple steatosis and steatohepatitis models. Therefore, clarifying the difference between the two may provide a new direction for the stage manner treatment of MAFLD.目的： 研究代谢（紊乱）相关脂肪性肝病(MAFLD）不同病变阶段，即单纯性脂肪肝和脂肪性肝炎病变阶段中肠道菌群的具体差异，为MAFLD相关的肠道菌群移植及靶向肠道菌群治疗提供新的方向。 方法： 分别以正常饮食、蛋氨酸-胆碱缺乏饮食（MCD）和高脂高果糖饮食（HFHF）喂养小鼠12周，构建单纯性脂肪肝和脂肪性肝炎模型；通过肝脏HE染色和天狼猩红染色观察其病理改变，应用qPCR方法对炎症和肝纤维化因子进行评估，全自动生化仪检测转氨酶及血脂变化，同时用16S rRNA测序观察各组小鼠粪便中肠道菌群的差异。两组间均数比较采用t检验，多组间均数比较采用单因素方差分析，非正态分布数据采用Kruskal-Wallis秩和检验。 结果： 通过小鼠肝脏HE病理切片和天狼猩红染色进行非酒精性脂肪性肝病活动度评分可知，MCD和HFHF组的炎症评分分别为2.12±0.18和1.06±0.24，肝纤维化评分为2.22±0.16和0.46±0.10，MCD饮食组小鼠肝脏炎症及纤维化程度明显重于HFHF饮食组（P < 0.001及P < 0.01）；HFHF组的脂质沉积重于MCD饮食组（P < 0.001），其评分值分别为2.36±0.17和1.60±0.24。同时炎症指标肿瘤坏死因子-a、趋化因子-2和肝纤维化指标血管平滑肌肌动蛋白、结缔组织生长因子在转录水平上对上述结果得到了验证。除此之外，相对于HFHF组，MCD组小鼠肠道菌群多样性降低（P < 0.05），其Simpson指数分别为0.31±0.10和0.42±0.05，Shannon指数为2.03±0.33和1.70±0.28，不同分组间菌群存在明显差异。相对于MCD饮食组，HFHF组中Desulfovibrio、Odoribacter、Roseburia菌群水平明显升高；相对于HFHF组，MCD饮食组小鼠Faecalibaculum、Parasutterella、Alistipes、Butyricimonas_virosa、Turicibacter_sp、Romboutsia_ilealis菌群水平升高，差异具有统计学意义（P < 0.05）。 结论： 单纯性脂肪肝和脂肪性肝炎模型中肠道菌群差别显著，明确两者差异可能为分阶段治疗MAFLD提供新的方向。.