目的 研究白头翁汤正丁醇提取物（butyl alcohol extract of Baitouweng Decoction，BAEB）对白念珠菌异常定植下的葡聚糖硫酸钠（dextran sulfate sodium salt，DSS）诱导的小鼠溃疡性结肠炎（ulcerative colitis，UC）的治疗作用，以及对Dectin-1/脾酪氨酸激酶（spleen tyrosine kinase，Syk）/NOD样受体热蛋白结构域相关蛋白3（NOD-like receptor thermal protein domain associated protein 3，NLRP3）信号通路的影响。方法 将105只C57BL/6小鼠随机分为对照组、DSS组、DSS＋白念珠菌组及BAEB低、中、高剂量（20、40、80 mg/kg）组和美沙拉嗪（200 mg/kg）组。对照组小鼠每日自由饮水；DSS组予3% DSS溶液，自由饮用连续7 d；其他组在DSS组基础上，在第1、3、5、7天ig白念珠菌（1×10⁸ CFU/只）。第8天开始分别ig相应药物，1次/d，连续7 d。每天称定小鼠质量，观察一般状态，收集粪便，采用平板培养法检测粪便真菌载荷。末次给药次日，处死小鼠，测量结肠长度，苏木素-伊红（HE）染色法进行结肠组织学分析；ELISA法检测结肠组织炎症因子白细胞介素-1β（interleukin-1β，IL-1β）和IL-18水平；免疫组化法检测结肠组织Occludin和闭锁连接蛋白-1（zonula occludens-1，ZO-1）表达；Western blotting检测结肠组织Dectin-1、核因子-κB（nuclear factor-κB，NF-κB）、Syk、凋亡相关微粒蛋白（apoptosis-associated speck-like protein containing CARD，ASC）、剪切型半胱氨酸天冬氨酸蛋白酶-1（cleaved cystein-asparate protease-1，cleaved Caspase-1）和NLRP3蛋白表达。结果 与对照组和DSS组比较，DSS＋白念珠菌组小鼠粪便培养出更多的白念珠菌（P＜0.01）；结肠黏膜损伤程度严重（P＜0.01）；结肠组织炎症因子IL-1β、IL-18水平明显升高（P＜0.01）；结肠组织Occludin和ZO-1蛋白表达明显下降（P＜0.05）；结肠组织NLRP3、NF-κB和Dectin-1蛋白表达水平显著升高（P＜0.01），ASC、cleaved Caspase-1和Syk蛋白表达水平显著降低（P＜0.05、0.01）。与DSS＋白念珠菌组相比，BAEB组小鼠肠道白念珠菌显著减少（P＜0.01）；结肠组织中IL-1β、IL-18水平下降（P＜0.05、0.01）；结肠组织Occludin和ZO-1蛋白表达均显著升高（P＜0.05、0.01）；BAEB低剂量组Syk蛋白表达水平显著降低（P＜0.01）；BAEB中剂量组ASC和Syk蛋白表达水平显著升高（P＜0.05、0.01），NLRP3和NF-κB蛋白表达水平显著降低（P＜0.05、0.01）；BAEB高剂量组NF-κB蛋白表达水平显著降低（P＜0.01），ASC蛋白表达水平显著升高（P＜0.01）。结论 BAEB可能通过抑制白念珠菌异常定植下Dectin-1/Syk通路所介导的NLRP3炎症小体过度活化，进而阻断IL-1β与IL-18的产生来发挥抗UC作用。

Objective To observe the therapeutic effect of butyl alcohol extract of Baitouweng Decoction (BAEB) on ulcerative colitis induced by dextran sodium sulfate (DSS) stimulated by abnormal colonization of Candida albicans in mice and Dectin-1/spleen tyrosine kinase (Syk)/NOD-like receptor thermal protein domain associated protein 3 (NLRP3) signaling pathway. Methods A total of 105C57BL/6 mice were randomly divided into control group, DSS group, DSS + C. albicans group and BAEB low-, medium- and high-dose (20, 40, 80 mg/kg) groups and mesalazine (200 mg/kg) group. Mice in control group were given free access to water every day; DSS group was given 3% DSS solution for seven consecutive days; Other groups were ig C. albicans (1×10⁸ CFU) on 1st, 3rd, 5th, and 7th days on basis of DSS group. On 8th day, mice were ig corresponding drugs, once a day for seven consecutive days. Body weight of mice was weighed every day, general state was observed, feces were collected, and fecal fungal load was detected by plate culture method. The day after last administration, mice were sacrificed, colon length was measured, and hematoxylin-eosin (HE) staining was used for colon histological analysis; ELISA was used to detect the inflammatory factor interleukin-1β (IL-1β) and IL-18 levels in colon tissue; Immunohistochemistry was used to detect the expression of Occludin and zonula occludens-1 (ZO-1) in colon tissue; Western blotting was used to detect protein expressions of Dectin-1, nuclear factor-κB (NF-κB), Syk, apoptosis-associated speck-like protein containing CARD (ASC), cleaved cystein-asparate protease-1 (cleaved Caspase-1) and NLRP3 in colon tissue. Results Compared with control group and DSS group, more C. albicans were cultured in feces of mice in DSS + C. albicans group (P < 0.01); Degree of colonic mucosal injury was severe (P < 0.01); Inflammatory factors IL-1β and IL-18 levels in colon tissue were significantly increased (P < 0.01); Occludin and ZO-1 protein expressions in colon tissue were significantly decreased (P < 0.05); NLRP3, NF-κB and Dectin-1 protein expressions in colon tissue were significantly increased (P < 0.01), ASC, cleaved Caspase-1 and Syk protein expressions were significantly decreased (P < 0.05, 0.01). Compared with DSS + C. albicans group, number of colony-forming units (CFU) of C. albicans in intestinal tract of mice in BAEB group was decreased (P < 0.01); Levels of IL-1β and IL-18 in colon tissue were decreased (P < 0.05, 0.01); Occludin and ZO-1 protein expressions in colon tissue were increased (P < 0.05, 0.01); Syk protein expression in low-dose BAEB group was significantly decreased (P < 0.01); ASC and Syk protein expressions in BAEB medium-dose group were significantly increased (P < 0.05, 0.01), NLRP3 and NF-κB protein expressions were significantly decreased (P < 0.05, 0.01); NF-κB protein expressions in BAEB high-dose group was significantly decreased (P < 0.01), ASC protein expression was significantly increased (P < 0.01). Conclusion BAEB may exert anti-UC effect by inhibiting the overactivation of NLRP3 inflammasome mediated by Dectin-1/Syk pathway under abnormal C. albicans colonization, thereby blocking the production of IL-1β and IL-18.

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国家自然科学基金资助项目(81774034);国家自然科学基金资助项目(81573725);安徽省自然科学基金资助项目(1808085QH286);安徽中医药大学重点项目(2019zrzd04);安徽省教育厅重点项目(KJ2017A301,KJ2018A0276)