人工蛹虫草子实体对Leiws肺癌荷瘤小鼠CD4^+CD25^+调节性T细胞的影响

Effect of cultured cordyceps militaris on CD4^+CD25^+ regulatory T cells in Lewis lung carcinoma bearing mice

目的:观察人工蛹虫草子实体(CCM)对Lewis肺癌移植瘤生长与转移的作用,同时检测CCM对荷瘤鼠CD4+CD25+调节性T细胞的影响,探讨其治疗肿瘤的免疫调节机制。方法:建立Lewis肺癌移植肿瘤模型。给予CCM处理后,观测肿瘤体积动态变化,计数转移灶数目,计算抑瘤率;采用流式细胞术分别于肿瘤生长第6、11、16和21d检测荷瘤鼠脾细胞CD4+CD25+的比例;荧光定量RT-PCR检测肺转移灶组织Foxp3和TGF-βmRNA的表达水平。结果:CCM可抑制Lewis肺癌移植肿瘤的生长与转移,肿瘤生长的早期这种抑制作用比较明显,在肿瘤生长21d抑制率虽为28.6%,但治疗组肺转移灶数目明显降低,P<0.01。与模型组相比,CCM治疗组CD4+CD25+T细胞增高缓慢,在肿瘤生长21d时,模型组脾脏CD4+CD25+T细胞比例为17.0%,而CCM组为13.5%,两者差异有统计学意义,P<0.01。CCM组肺转移灶组织Foxp3和TGF-βmRNA的表达也明显低于模型组。结论:CCM抑制肿瘤生长和转移作用可能与CCM下调荷瘤体内CD4+CD25+T细胞,抑制TGF-β分泌,从而激发机体的抗肿瘤免疫相关。

OBJECTIVE： To study the inhibitory effect of cultured cordyceps militaris（CCM）on growth and metastasis of Lewis lung carcinoma and potential relationship with CD4^＋ CD25^＋ regulatory T cells. METHODS： The models were established by injected Lewis lung cancer cells subcutaneously to the right axilla of C57BL/ 6 mice. The dynamic change of tumor volume, tumor weight, and number of tumor colonies in lung were observed afler treated with CCM. The changes of percentage of CD4^＋ CD25^＋ regulatory T cells were detected at various time d6, d11 , d16 , d21 by flow cytometry （FCM） and the mRNA expression of Foxp3 and TGF-β in I.ung metastasis were analyzed by quantitative RT PCR after treatment with CCM. RESULTS： CCM could inhibit growth and metastasis of Lewis lung cancer, especially at early stage of tumor growth. Although the inhibitory rate was（28.6%）at advanced stage, the number of tumor colonies in lung in CCM group was lower than that of control group（P〈0. 01）. Compared with control group, the percentage of CD4^＋ CD25^＋ regulatory T cells in CCM treatment group increased slowly. The average percentage of CD4^＋ CD25^＋ regulatory T cells from spleen of CCM and control group were 13.5% and 17.0% respectively at d21 （P〈0. 01）. The mRNA expression of Foxp3 and TGF-β in I.ung metastasis was also lower than control group. CONCLUSIONS： CCM can inhibit growth and metastasis of Lewis lung carcinoma. This effect partially is due to decreasing CD4^＋ CD25^＋ regulatory T cells and inhibiting TGF-β secretion, thus restore the anticancer immune response.