艾灸预处理天枢穴对溃疡性结肠炎大鼠结肠TLR4/TRIF信号通路调节作用的研究

Study on the Regulating Effect of Moxibustion Pretreatment at Tianshu(ST25) on TLR4/TRIF Signaling Pathway in UC Rats

目的观察艾灸预处理天枢穴对溃疡性结肠炎(ulcerative colitis,UC)大鼠结肠TLR4/TRIF信号通路的影响,探讨艾灸预处理防治UC的作用机制.方法将28只SD雄性大鼠随机分为正常组、模型组、隔药灸预处理组和温和灸预处理组.采用4%葡聚糖硫酸钠水溶液连续饮用7 d制备UC模型.隔药灸预处理组、温和灸预处理组先干预7 d后,模型组、隔药灸预处理组、温和灸预处理组再制备UC模型.采用HE染色法,观察大鼠结肠组织病理学变化;应用免疫组化、免疫印记技术检测大鼠结肠TLR4、TRIF、TRAF6、IRF3、IKK的蛋白表达.结果模型组大鼠结肠黏膜结构损伤较正常组明显加重;隔药灸预处理组和温和灸预处理组,结肠黏膜结构损伤较模型组明显改善.与正常组比较,模型组结肠TLR4、TRIF、TRAF6、IRF3、IKK蛋白表达均显著升高(P<0.05);与模型组比较,隔药灸预处理组、温和灸预处理组结肠TLR4、TRIF、TRAF6、IRF3蛋白表达均显著降低(P<0.05),隔药灸预处理组结肠IKK蛋白表达显著降低(P<0.05).结论艾灸预处理天枢穴能下调UC大鼠结肠TLR4、TRIF、TRAF6、IRF3蛋白表达;下调TLR4/TRIF信号通路相关分子的蛋白表达可能是艾灸预处理防治UC的作用机制之一.

Objective To observe the effect of moxibustion pretreatment at Tianshu (ST25) on TLR4/TRIF signaling pathway in ulcerative colitis (UC) rats, and to explore the mechanism of moxibustion pretreatment in preventing and treating UC. Method Twenty-eight male Sprague-Dawley rats were randomly divided into a normal control (NC) group, a model control (MC) group, a herb-partitioned moxibustion pretreatment (HM+P) group and a warm moxibustion pretreatment (WM+P) group. The UC model was established by intake of 4% dextran sodium sulfate solution for 7 consecutive days. The HM+P and the WM+P groups were treated with moxibustion for 7 days before the model was established in these two groups and the MC group. The pathological changes of rat colon tissues were observed by HE staining. The protein expressions of toll-like receptor 4 (TLR4), TIR-domain-containing adaptor inducing interferon-?(TRIF), TNF receptor-associated factor 6 (TRAF6), interferon regulatory factor 3 (IRF3) and inhibitor of nuclear factor kappa-B kinase (IKK) in rat colon tissues were detected by immunohistochemistry and Western blot. Result The colonic mucosal structure damage in the MC group was significantly worse than that in the NC group;the colonic mucosal structure injury was significantly improved in the HM+P and the WM+P groups compared with that in the MC group. Compared with NC group, the TLR4, TRIF, TRAF6, IRF3 and IKK protein expressions in rat colon tissues were significantly increased in the MC group (P<0.05);compared with the MC group, the protein expressions of TLR4, TRIF, TRAF6 and IRF3 in colon tissues were significantly decreased in the HM+P and the WM+P groups (P<0.05), and the protein expression of IKK in colon tissues was significantly decreased in the HM+P group (P<0.05). Conclusion Moxibustion pretreatment at Tianshu (ST25) can down-regulate the protein expressions of TLR4, TRIF, TRAF6 and IRF3 in colon tissues of UC rats;down-regulation of the protein expressions of the involved factors on TLR4/TRIF pathway may be one of the mechanisms of moxibustion pretreatment in preventing and treating UC.