水飞蓟素通过调控骨髓来源的抑制性细胞抗肺癌机制的实验研究

The anti-lung cancer mechanisms of Silymarin via inhibiting myeloid-derived suppressor cells

目的:研究水飞蓟素通过调控骨髓来源的抑制性细胞(MDSC)的抗肺癌机制。方法:我们在C57/BL6小鼠上构建了路易斯(Lewis)肺癌细胞转移瘤模型,灌胃给予不同浓度(25、50 mg/kg,每天一次)的水飞蓟素。测量小鼠肿瘤体积及体重变化。用免疫组化方法检测Lewis肺癌细胞肿瘤增殖相关指标增殖细胞核抗原(PCNA)的表达。通过TUNEL染色检测肺癌细胞的凋亡情况。通过免疫组化检测组织中CD8^+T细胞浸润及功能。通过流式细胞术检测CD11b^+Gr-1^+的MDSC百分比。通过Q-PCR检测肿瘤组织中Arg-1、i NOS2及MMP9的表达。结果:25和50 mg/kg的水飞蓟素剂量依赖地抑制肿瘤生长,诱导肿瘤细胞凋亡。水飞蓟素增加了CD8^+T细胞浸润;减少了肿瘤组织中MDSC的比例,肿瘤组织中Arg-1、i NOS2及MMP9(MDSC功能相关)m RNA表达的减少也证实了MDSC功能的减弱。结论:水飞蓟素抑制了MDSC,促进CD8^+T细胞浸润及功能,抑制模型中肿瘤生长,为水飞蓟素治疗肺癌提供了依据。

Objective:To study the anti-lung cancer mechanisms of Silymarin via inhibiting myeloid-derived suppressor cells(MDSC).Methods:We developed a mouse xenograft model of Lewis lung cancer cells(LLC)in C57/BL6 mice and administered(i.g)Silymarin(25,50 mg/kg,once a day)dose dependently.Tumor volumes and mice body weight were measured.The expression of proliferating cell nuclear antigen(PCNA)related to tumor proliferation was detected by immunohistochemistry(IHC)staining.The apoptosis of LLC cells was detected by TUNEL staining.Tumor-infiltrating CD8+T cells in LLC xenografts were detected by IHC staining.The percentage of CD11b+Gr-1+MDSC was detected by flow cytometry.RNA was extracted from tumor tissue of mice and the expressions of Arg-1,iNOS2 and MMP9 mRNA were determined by Q-PCR.Results:Silymarin significantly suppressed tumor growth and induced apoptosis of cells in tumor tissues at a dose of 25 and 50 mg/kg.Silymarin treatment enhanced the infiltration and function of CD8+T cells.Finally,Silymarin reduced the proportion of myeloid-derived suppressor cells(MDSC)in the tumor tissue and the mRNA expressions of inducible nitric oxide synthases-2(iNOS2),arginase-1(Arg-1)and MMP9,which indicated that the function of MDSC in tumor tissues was suppressed.Conclusion:Altogether,our data here showed that Silymarin inhibited the MDSC and promoted the infiltration and function of CD8+T cells thus suppressed the growth of LLC xenografts,which provides evidence for the possible use of Silymarin against lung cancer.