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目的 探讨哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路在柴苓汤诱导调节性T细胞(regulatory T cells,Tregs)增殖以及诱导小鼠同种异体心脏移植免疫耐受中的作用.方法 以CC57BL/6j(H-2b)小鼠为供体、C3 H/He(H-2k)小鼠为受体建立腹部心脏移植模型,术后随机分为对照组、雷帕霉素组和柴苓汤组,每组20只.每天分别用无菌生理盐水、雷帕霉素(1.5 mg/kg)和柴苓汤(2 g/kg)灌胃,共7天.术后观察3组小鼠移植心脏生存期及心脏形态学改变;术后第7天,采用流式细胞术和RT-PCR分别检测受体脾脏Tregs百分率和Foxp3 m RNA的表达量;RT-PCR和Western blot检测mTOR通路分子的mRNA(mTOR、P70s6k)和磷酸化蛋白(p-mTOR、p-P70s6k)的表达水平.结果 柴苓汤组和雷帕霉素组移植心脏生存时间较对照组均明显延长(P＜0.05);术后第7天,病理结果显示对照组出现典型细胞免疫性损伤改变,柴苓汤组和雷帕霉素组少许炎症细胞浸润.柴苓汤组和雷帕霉素组Tregs百分率和Foxp3 mRNA表达量较对照组均明显增加(P＜0.05);柴苓汤组和雷帕霉素组mTOR通路分子的mRNA和磷酸化蛋白的表达较对照组均明显下调(P＜0.05),柴苓汤组和雷帕霉素组间比较,差异均无统计学意义(P＞0.05).结论 柴苓汤可以通过抑制mTOR通路分子表达来诱导Tregs增殖,从而实现诱导小鼠心脏移植免疫耐受.“,”Objective To observe the roles of mammalian target of rapamycin (mTOR) pathway in Chailing Decoction (CLD) inducing proliferation of regulatory T cells (Tregs) and immune tolerance of allogeneic heart transplantation in mice.Methods C57BL/6j(H-2b) mice were used as donors and C3H/He(H-2k) mice as recipients to establish the abdominal heart transplantation model.The recipient mice were randomly divided into the control group,the Rapamycin group,and the CLD group,20 in each group.Three groups of mice were fed with sterile saline,Rapamycin (1.5 mg/kg),and CLD (2 g/kg) by gastrogavage,once per day for 7 successive days,respectively.The survival time of transplanted heart and morphological changes of heart were observed after transplantation.On the 7th day after transplantation,the percentage of Tregs in mouse splenocytes and mRNA expression level of forkhead box protein P3 (Foxp3) were detected by flow cytometry and RT-PCR respectively.mRNA and phosphotyrosine protein expression levels of mTOR and P70s6k were assayed by RT-PCR and Western blot.Results The survival time of the grafts of the CLD group and the Rapamycin group were significantly longer than that of the control group (P ＜0.05).On the 7th day after transplantation,pathological results showed that typical cellular immune injury occurred in the control group,but with less infiltrated inflammatory cells in the CLD group and the Rapamycin group.The percentage of Tregs and the expression of Foxp3 mRNA were significantly increased in the CLD group and the Rapamycin group,as compared with those of the control group (P ＜ 0.05).mRNA and phosphotyrosine protein expression levels of mTOR pathway molecules were significantly down-regulated in the CLD group and the Rapamycin group,as compared with those of the control group (P ＜0.05).But there was no significant difference between the CLD group and the Rapamycin group (P ＞0.05).Conclusion CLD could induce the proliferation of Tregs by inhibiting the expression of mTOR pathway molecules,so as to induce immune tolerance of mice in heart transplantation.