调节性T细胞对小鼠肝纤维化的促进作用

Regulatory T cells promote liver fibrosis in mice

目的:研究调节性T细胞(regulatory T cells,Tregs)在肝纤维化发展中的作用.方法:实验小鼠分为3组:肝纤维化组、肝纤维化+CD25抗体组(下调Tregs)、对照组.用四氯化碳(carbon tetrachloride,CCl4)诱导小鼠肝纤维化,30%CCl4腹腔注射4 wk后,选取部分小鼠腹腔注射纯化的CD25单克隆抗体(PC61培养上清),下调体内Tregs水平.对照组小鼠腹腔注射等体积生理盐水.流式细胞分析检测肝内CD4+CD25+T细胞水平,用免疫荧光法标记肝星状细胞活化标志α-平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)的表达,Realtime PCR检测肝内Foxp3以及Ⅰ型胶原和Ⅲ型胶原的表达.结果:流式细胞分析显示肝纤维化小鼠肝内Tregs明显高于对照组,注射CD25抗体后,肝内CD4+CD25+T细胞下降50%以上,同时Realtime PCR显示Foxp3表达比纤维化组也明显下降.免疫荧光显示下调体内Tregs水平后,α-SMA表达较肝纤维化小鼠显著减少,同时Ⅰ型胶原和Ⅲ型胶原也减少.结论:Tregs对小鼠肝纤维化发展具有促进作用.

AIM： To investigate the role of regulatory T cells （Tregs） in the development of liver fibrosis in mice. METHODS： Experimental mice were dividedinto three groups： a liver fibrosis group, a liver fibrosis ＋ anti-CD25 group and a control group. Liver fibrosis was induced by intraperitoneal in- jection of 30% carbon tetrachloride （CC14）. Four weeks later, mice in the liver fibrosis ＋ anti- CD25 group were intraperitoneally injected with the purified CD25 monoclonal antibody （PC61 culture supernatant） to deplete Tregs. The mice injected with the same volume of saline were used as controls. Flow cytometry was used to detect the level of liver CD4＋CD25＋ T cells, im- munofluorescence was used to stain the activat- ed hepatic stellate cells （α-SMA）, and real-time PCR was used to detect the expression of Foxp3 and type- I and -III collagen in the liver.RESULTS： Flow cytometry analysis showed that the number of Tregs was significantly high- er in liver fibrosis mice; after injection of CD25 antibody, CD4＋CD25＋ T cells in the liver were decreased by 50%. Real-time PCR showed that Foxp3 mRNA expression was significantly de- creased compared to the fibrosis group. Immu- nofluorescence results showed that c^-SMA was significantly reduced after Tregs depletion, com- pared to liver fibrosis mice. The mRNA levels of type- I and type-III collagen were also decreased after Tregs depletion.CONCLUSION： Tregs can promote liver fibrosis in mice.