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目的 探讨髓来源抑制细胞(MDSCs)对非酒精性脂肪性肝炎(NASH)小鼠的影响.方法 (1)将6～8周龄雄性C57BL/6小鼠,随机分为正常饮食组、CDAA组(给予胆碱缺乏的氨基酸饮食)、CSAA组(给予胆碱充分的氨基酸饮食).(2)造模成功后,取小鼠血清检测生化指标;留取肝组织行HE染色;流式细胞技术检测各组小鼠外周血T细胞亚群的改变以及体内肝、脾、血液、骨髓中CD11b+Gr-1+的MDSCs细胞的比例、亚型改变.(3)用磁珠分选技术纯化骨髓来源的Gr-1 high Ly-6G+,并将纯化的Gr-1 high Ly-6G+通过尾静脉注射过继转移入NASH小鼠,检测肝功能血清学指标及病理染色证实MDSCs对NASH小鼠的作用 (1)各组小鼠体重、肝指数比较差异无统计学意义(P＞0.05);血清学指标:模型组ALT、AST、血糖、IL-6、INF-y均较正常组明显升高(P＜0.001);镜下表现:CDAA、CSAA组肝脏均显示不同程度的脂肪变性,CDAA组更明显.(2)流式细胞检测显示:①CDAA组CD4+ CD8-T、CD4-CD8+T百分比下降,CD4/CD8比值呈下降趋势;②骨髓MDSCs:CDAA组＞正常组(P＜0.05);外周血MDSCs:CDAA组＜正常组(P＞0.05);肝脏MDSCs:CDAA组＜正常组(P＜0.01);③骨髓、肝脏CD11b+Gr-1high Ly-6G+ (G-MDSC):CDAA组＞正常组(P＜0.01),CD11b+Gr-1dimLy6G-(M-MDSC)呈下降趋势:CDAA组＜正常组(P＜0.05);(3)接受正常小鼠骨髓来源Gr-1 high Ly-6G+ MDSCs的NASH小鼠血清AST、ALT水平明显降低(P＜0.01),组织学病理改变减轻.结论 (1)CDAA饮食可成功建立NASH小鼠模型.(2)CDAA饮食诱导的NASH小鼠可出现免疫功能紊乱,骨髓MDSCs亚群发生改变且以CD11b+Gr-1highLy-6G+(G-MDSC)的增加为主.(3)正常小鼠骨髓来源的Gr-1highLy-6G+MDSCs具有缓解NASH病变的作用.“,”Objective To investigate the effects of myeloid-derived suppressor cells (MDSCs) on nonalcoholic steatohepatitis mice.Methods (1) Male C57BL/6 mice aged 6-8 weeks were randomly divided into normal diet group,CDAA group(choline deficient amino acid diet) and CSAA group (choline sufficient amino acid diet).(2) After the success of the non-alcoholic steatohepatitis model,serum was collected from some mice to detect biochemical indexes;Liver tissue was retained for microscopic observation by hematoxylin-eosin (HE) staining;The changes of T cell subsets in peripheral blood of mice in each group were detected by flow cytometry.In addition,The proportion and subtype of CD1 lb + Gr-1 + MDSCs cells in liver,spleen,blood and bone marrow were also detected by flow cytometry.(3)The bone marrow-derived Gr-1highLy-6G+ was purified by magnetic bead sorting technique,and the purified Gr-1highLy-6G+ was transferred into non-alcoholic steatohepatitis (NASH) mice by tail vein injection.The role of MDSCs in NASH was analyzed by detection of serological indexes of liver function and pathological dyeing.Results (1) There was no significant difference in body weight and liver index between the groups (P ＞ 0.05).Serological indicators:alanine aminotransferase (ALT),aspartate aminotransferase (AST),blood glucose,interleukin (IL)-6 and interferon-γ (INF-γ) in the model group were significantly higher than those in the normal group (P ＜ 0.01);microscopic findings:the liver in CDAA,CSAA group showed varying degrees of steatosis;the steatosis in CDAA group was much more severe.(2) Flow cytometry showed that ① the percentage of CD4 + CD8-T and CD4-CD8 + T decreased and CD4/CD8 ratio decreased in CDAA group;② the bone marrow MDSCs of CDAA group is lower than that of normal group (P ＜ 0.05);the MDSCs of peripheral blood in CDAA group is lower than that of normal group (P ＞ 0.05);the MDSCs of liver in CDAA group is lower than that of normal group (P ＜ 0.01).③ subgroup comparison,bone marrow,liver CD11 b + Gr-1 high Ly-6G + (G-MDSC):CDAA group ＞ normal group (P ＜ 0.0l),CD11 b + Gr-1 dim Ly-6G-(M-MDSC) showed a downward trend,CDAA group ＜ normal group;(3) Serum AST and ALT levels of NASH mice who receiving Gr-1highLy-6G+ MDSCs from normal bone marrow were significantly decreased (P ＜ 0.001),and histopathological changes were alleviated.Conclusions (1) The NASA mouse model can be successfully established on the CDAA diet.(2) The CDAA-induced NASH mice may have immune dysfunction,mainly manifesting in the change of bone marrow MDSCs subpopulations and the increase of CDllb + Gr-1highLy-6G+ (G-MDSC).(3) MDSCs derived from normal mouse bone marrow can alleviate the pathological changes of NASH.