香加皮三萜类化合物对甲基苄基亚硝胺诱导的食管癌大鼠调节性T细胞功能的影响

Effects of triterpenes compound of cortex periplocae on regulatory T cells function in N-nitrosomethylbenzylamine-induced esophageal tumorigenesis in F344 rats

目的:探讨香加皮三萜类化合物(triterpenes compound of cortex periplocae,TCCP)对甲基苄基亚硝胺(N_nitrosomethylbenzylamine,NMBA)诱导的食管癌大鼠CD4+CD25+调节性T细胞功能的影响。方法:健康雄性F344大鼠40只,随机分为模型组(0.5mg/kg NMBA皮下注射)、治疗组(0.5mg/kg NMBA皮下注射及10mg/kg TCCP肌肉注射)、大豆油对照组(肌肉注射大豆油1ml/kg)和正常对照组,每组10只。各组每周给受试物3次,连续5周。分别在给受试物后第9周和第15周抽取4组大鼠外周血各1ml。用流式细胞仪检测大鼠外周血中CD4+T细胞和CD4+CD25+调节性T细胞(Tr细胞)的水平。另留取血清用ELISA法检测大鼠外周血白细胞介素IL_2、IL_10和转化生长因子TGF_β1的含量。结果:与正常对照组相比,NMBA给药后第9周和第15周,模型组外周血中CD4+T细胞比例均显著降低(P均<0.05),而CD4+CD25+Tr细胞比例均显著升高(P均<0.05)。与同时期模型组比较,TCCP治疗组在给药后第9周和第15周外周血中CD4+T细胞比例升高,CD4+CD25+Tr细胞比例降低,差异均具有统计学意义(P均<0.05)。NMBA给药后第9周和第15周,模型组大鼠外周血中IL-10、TGF-β1水平显著高于正常对照组(P均<0.05),经TCCP治疗后显著下降(P均<0.05);大鼠外周血中IL-2水平则呈现与之相反的趋势。结论:NMBA诱导大鼠食管癌后外周血中CD4+CD25+Tr细胞水平增加,TCCP可以通过抑制CD4+CD25+Tr细胞活化来纠正食管癌发生、发展过程中所致免疫细胞抑制状态,改善NMBA诱导的食管癌大鼠细胞免疫功能紊乱。

OBJECTIVE：To investigate the effects of triterpenes compound of cortex periplocae（TCCP）on CD4^＋ CD25^＋ regulatory T cells in peripherial blood in N-nitrosomethylbenzylamine（NMBA）-induced esophageal tumorigenesis in F344 rats.METHODS：40 male F344 rats（5-6 weeks of age）were randomly divided into four groups：rats were treated with 0.5 mg/kg NMBA only as model group and rats received NMBA 0.5 mg/kg s.c.plus TCCP 10 mg/kg i.m.as TCCP treatment groups and those treated with soya oil 1 ml/kg intramuscularily（i.m.）acted as soya oil control and normal control groups.10 rats in each group were treated thrice per week for 5 weeks.Then the numbers of CD4^＋ and CD4^＋CD25^＋ regulatory T cells in peripheral blood were counted by flow cytometry at weeks 9 and 15.The levels of IL-2,IL-10 and TGF-β1 in peripheral blood were detected with ELISA.RESULTS：After 0.5 mg/kg NMBA treatment for 9 weeks,CD4^＋ T cells in peripheral blood of NMBA group rats were decreased significantly whilst CD4^＋CD25^＋ regulatory T cells were significantly increased compared with the control group（P0.05）.At weeks 9 and 15,TCCP treatment decreased the proportions of CD4^＋CD25^＋ regulatory T cells,while the proportions of CD4^＋ cells were significantly increased（P0.05）,compared with NMBA group.At week 9 after NMBA treatment,the protein levels of TGF-β1 and IL-10 in peripheral blood were significantly higher than those in normal control group and soya controlgroup.However the protein levels of IL-2 were significantly decreased,as compared with normal control.TCCP could decrease the expression of IL-10 and TGF-β1,but increase the expression of IL-2.CONCLUSION：In rats the expression of CD4^＋CD25^＋ regulatory T cells in peripheral blood were enhanced after treatment with NMBA,while the triterpenes compound of Cortex Periplocae effectively inhibited the expression,thus it could improve the immune dysfunction in experimental esophageal tumorigenesis in F344 rats.