半夏泻心汤对AOM/DSS致炎症相关性结直肠癌小鼠的保护作用

Protective Effect of Banxia Xiexin Decoction on AOM/DSS-induced Colitis Associated Cancer Mice

关键词:  半夏泻心汤  结直肠癌  核转录因子kappa B  巨噬细胞  上皮-间质转化

Key words:  Banxia Xiexin decoction  colitis-associated cancer  nuclear factor kappa B  macrophage  epithelial-mesenchymal transition

摘要:

目的 探讨半夏泻心汤对结肠炎相关结直肠癌(colitis associated cancer，CAC)小鼠的影响及相关作用机制。方法 将75只C57BL/6小鼠随机均分为正常组、模型组、美沙拉嗪组和半夏泻心汤低、高剂量组。除正常组外，其余各组小鼠均采用腹腔注射氧化偶氮甲烷联合口服葡聚糖硫酸钠法构建CAC模型，分别给予半夏泻心汤和美沙拉嗪进行干预。观察并记录用药后全部小鼠一般情况，监测体质量、疾病活动指数变化情况；利用HE染色观察结肠组织病理学改变情况；免疫组化检测PCNA、NF-κB P65和IκB-α蛋白表达水平；qRT-PCR检测结肠组织IL-17A、N-cadherin和Bcl-2 mRNA水平；免疫荧光检测巨噬细胞标记物表达情况；Western blotting分析各组结肠组织中NF-κB、E-cadherin和N-cadherin 蛋白表达。结果 正常组无明显肿瘤发生，模型组小鼠体质量明显减轻，结肠瘤体数量增多，半夏泻心汤组结肠长度及肿瘤数量、炎性细胞浸润程度均较模型组明显改善。免疫组化结果显示，模型组小鼠结肠组织PCNA、NF-κB P65和IκB-α蛋白表达显著升高(P<0.01)；免疫荧光结果显示，模型组小鼠结肠组织F4/80、CD80和CD206阳性巨噬细胞数目增多(P<0.05或P<0.01)；qRT-PCR结果显示，模型组小鼠结肠组织中IL-17A、N-cadherin和Bcl-2 mRNA水平明显升高(P<0.01)，而E-cadherin mRNA水平显著下降(P<0.01)；Western blotting结果显示，模型组小鼠结肠组织NF-κB和N-cadherin蛋白表达水平均显著升高(P<0.01)；E-cadherin蛋白水平明显下降(P<0.01)。与模型组比较，半夏泻心汤和美沙拉嗪组明显改善上述指标，差异具有统计学意义(P<0.05或P<0.01)，且以半夏泻心汤高剂量组变化更为显著。结论 半夏泻心汤对CAC小鼠表现出良好的抗炎及抑瘤作用，抑制结肠组织巨噬细胞的活化并促进其向M2型极化；降低肿瘤相关蛋白PCNA和Bcl-2的表达，阻断EMT相关蛋白(E-cadherin和N-cadherin)进展，其机制可能与抑制NF-κB P65和IκB-α的活化调控NF-κB信号通路有关。

Abstract:

OBJECTIVE To investigate the effect of Banxia Xiexin decoction(BXD) on colitis associated cancer(CAC) mice and its related mechanism. METHODS Seventy-five C57BL/6 mice were randomly divided into normal group, model group, Banxia Xiexin decoction low-dose group, high-dose group and mesalazine group. Except for the normal group, the mice in the other groups were intraperitoneally injected with azoxymethane combined with oral dextran sodium sulfate to establish the CAC model. BXD and mesalazine were given respectively for intervention. The general conditions of all mice were observed and recorded, and the changes of body weight, disease activity index, colon length and tumor number were monitored. HE staining was utilized to observe the pathological changes of colon tissue. The expression levels of PCNA, NF-κB P65 and IκB-α were detected by immunohistochemistry. The mRNA levels of IL-17A, N-cadherin, E-cadherin and Bcl-2 were detected by qRT-PCR. Macrophage infiltration was measured using immunostaining analysis. Western blotting was applied to analyze the expression of NF-κB, E-cadherin and N-cadherin proteins in colon tissues of each group. RESULTS There was no significant tumor occurrence in the normal group, while the body weight of the model group mice was significantly reduced and the number of colon tumors increased. The colon length, number of tumors, and degree of inflammatory cell infiltration in the BXD group were significantly improved compared to the model group. Immunohistochemical results showed that the expression of PCNA, NF-κB P65 and IκB-α protein in colon tissue of model group was remarkably increased (P<0.01). Immunofluorescence results showed that the number of F4/80, CD80 and CD206 positive macrophages in the colon tissue of the model group increased (P<0.05 or P<0.01). The results of RT-PCR demonstrated that the levels of IL-17A, N-cadherin and Bcl-2 mRNA in the colon tissue of the model group were significantly increased (P<0.01), while the level of E-cadherin mRNA was fundamentally decreased (P<0.01). Western blotting results displayed that the expression levels of NF-κB and N-cadherin protein in colon tissue of model group were up-regulated (P<0.01), while E-cadherin was significantly down-regulated (P<0.01). Compared with the model group, the changes of the above indexes in the BXD and mesalazine groups were ameliorated, with statistical differences (P<0.05 or P<0.01), and the changes in the BXD high-dose group were more significant. CONCLUSION BXD exhibits strong anti-inflammatory and anti-tumor benefits in CAC mice, inhibiting macrophage activation in colon tissue and promoting M2 polarization, while reducing the expression of tumor associated proteins PCNA and Bcl-2, and block the progression of EMT related proteins (E-cadherin and N-cadherin). The mechanism may connect to suppressing NF-κB P65 and IκB-α activation to regulate the NF-κB signaling pathway.