Background:The tumor immune microenvironment is one of the most important prognostic factors in liver metastasis from colorectal cancer.Low-dose cyclophosphamide(CTX)is widely believed to be involved in the modulation of the immune system.However,the underlying mechanism of low-dose CTX remains unknown.This study aimed to investigate the antitumor immunity of low-dose CTX in the treatment of colon-cancer liver metastasis.Methods:Thirty mice were randomly divided into five groups.After liver metastasis was established in colon-cancer models,mice in the treatment groups were injected with low-dose CTX(20 mg/kg)at different time points.Liver and spleen tissues were examined for T-cell markers via flow cytometry.Interleukin(IL)-10 and transforming growth factor(TGF)-b1 expression levels in liver tissues were analysed by immunohistochemistry.Serum interferon(IFN)-c and IL-10 levels were detected by enzyme-linked immunosorbent assay.An additional 20 mice were randomly allocated into two groups and the survival times were recorded.Results:The expression levels of CD4^(+)T cells,CD8^(+)T cells,and IFN-c were down-regulated,whereas those of IL-10 and TGF-b1 were up-regulated in liver metastasis from colon cancer in mice.Furthermore,the local and systemic microenvironments of the liver were altered,which led to reduced antitumor immune responses and subsequently liver metastasis.However,treatment with low-dose CTX reversed these effects.The survival times of mice treated with low-dose CTX were significantly longer than those of the other groups.Conclusions:Low-dose CTX exerts its antitumor activity by changing the systemic and local immune microenvironments and enhancing immune regulation inmice.CTX could be used as a drug to prevent and treat livermetastasis from colon cancer.
目的观察活血除痹汤对硬皮病小鼠皮肤血小板衍生生长因子A(PDGF-A)和转化生长因子-β(TGF-β)表达的影响,探讨其可能的作用机制。方法 30只小鼠随机分为空白组、模型组和中药高、中、低剂量组,每组6只。除空白组外,其余各组小鼠均予皮内注射盐酸博来霉素0.1 m L,连续3周,建立硬皮病小鼠模型。第4~7周,空白组和模型组予等量蒸馏水灌胃,中药高、中、低剂量组分别给予活血除痹汤44.8、22.4、11.2 g/(kg·d)灌胃,每日1次。观察各组小鼠皮肤及肺组织病理学改变,HE染色测量皮肤厚度,免疫组化检测皮损组织PDGF-A、TGF-β和Ⅰ、Ⅲ型胶原(COL-Ⅰ/COL-Ⅲ)的蛋白表达。结果模型组小鼠真皮明显增厚,胶原纤维明显增粗,并有炎性细胞浸润;肺组织可见肺泡间隔增厚,有成纤维细胞形成并伴大量单核细胞浸润;与模型组比较,中药各剂量组皮肤厚度、真皮胶原纤维膨大增厚程度及肺泡间隔增粗程度均有所减轻。模型组PDGF-A、TGF-β、COL-Ⅰ及COL-Ⅲ蛋白表达均较空白组明显增加(P<0.01);中药各剂量组上述指标阳性表达均较模型组明显降低(P<0.01)。PDGF-A、TGF-β表达与COL-Ⅰ、COL-Ⅲ表达呈正相关。结论活血除痹汤可能通过抑制PDGF-A、TGF-β的表达,抑制胶原表达和成纤维细胞的生成,达到治疗硬皮病的作用。
