目的在体内外水平研究大蒜新素对小鼠巨细胞病毒(murine cytomegalovirus, MCMV)感染导致调节性T细胞(regulatory T cells, Treg)异常扩增的抑制作用。方法 72只MCMV感染小鼠随机分为安慰剂组和大蒜新素治疗组;并设72只同期模拟感染小鼠为对照, 随机分为模拟感染对照组和大蒜新素对照组。分别于大蒜新素处理后1、7、14、28、60、120 d处死小鼠, 获得脾细胞待测。采用Western blotting法检测脾细胞中Foxp3的蛋白表达强度;流式细胞术分析CD4₊CD25₊Foxp3₊Treg细胞在脾细胞中所占比率的变化。采用小鼠胚胎成纤维细胞对大蒜新素的最大耐受浓度处理MCMV感染的胚胎成纤维细胞3 d后, 采用Real-time PCR法和Westernblotting法分别检测T细胞中Foxp3 mRNA和蛋白的表达水平。结果整体研究发现, 大蒜新素对正常小鼠脾细胞中Foxp3蛋白表达和Treg细胞比率均无显著影响;但是在MCMV感染小鼠, 大蒜新素可在感染慢性期显著减少Foxp3蛋白表达强度、降低调节性T细胞比率。体外细胞模型发现, 最大耐受浓度的大蒜新素加入共培养体系后可部分拮抗MCMV诱导的Foxp3基因和蛋白表达上调。结论大蒜新素在体内外均可显著纠正MCMV感染导致的Treg异常扩增。大蒜新素通过影响Treg增殖进而增强抗病毒免疫而有利于机体清除CMV病毒, 可能是大蒜新素诱导抗CMV免疫的另一重要机制。

Objective To investigate the effect of allitridin on regulatory T cells(Treg) amplification induced by murine cytomegalovirus(MCMV) in vivo and in vitro.Methods Seventy two MCMV infected mice were randomly divided into two groups,allitridin-treated group and placebo-treated group.Another 72 simulated-infection mice served as controls and were randomly divided into allitridin-treated control and simulated-infection control.The mice were sacrificed for collection splenocytes at day 1,7,14,28,60,and 120 after treatment.The protein expression of Foxp3 and the proportion of CD4+CD25+Foxp3+ Tregs in splenocytes were measured by Western blotting and flow cytometry(FCM),respectively.Maximum tolerance concentration(MTC) allitridin was added to the mouse embryo fibroblasts(MEF) and MCMV co-culture system.After 3 d,changes of Foxp3 mRNA and protein expression were measured by real-time PCR and Western blotting,respectively.Results In vivo,allitridin had no influence to the Foxp3 expression and Treg proportion of uninfected mice,but could notably down-regulate those of infected mice during chronic infection period.In vitro,the treatment of MTC allitridin could partly block MCMV induction of Foxp3 mRNA and protein expression.Conclusion Allitridin could partly retrieve MCMV induced Treg expansion and Treg-mediated anti-MCMV immunosuppression no matter in vivo or in vitro.By using this strategy,allitridin could enhance the specific cellular immune responses against cytomegalovirus(CMV) and be favourable for clearance of CMV viruses from host,suggesting another key mechanism of allitridin′s against CMV.

国家自然科学基金资助项目(30572345)