目的 研究五味子乙素（schisandrin B，Sch B）对2,4,6-三硝基苯磺酸（2,4,6-trinitrobenzenesulfonic acid solution，TNBS）诱导的大鼠溃疡性结肠炎（ulcerative colitis，UC）的治疗作用，探讨其通过调控细胞自噬相关蛋白及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）/半胱氨酸天冬氨酸蛋白酶-1（cystein-asparate protease-1，Caspase-1）/消皮素D（gasdermin D，GSDMD）信号通路减轻结肠上皮细胞焦亡的分子机制。方法 SD大鼠随机分为对照组、模型组、美沙拉嗪（100 mg/kg）组和Sch B低、中、高剂量（10、20、50 mg/kg）组，每组10只，雌雄各半。构建TNBS诱导的UC模型，给药干预14 d后，观察大鼠一般状态，检测疾病活动指数（disease activity index，DAI）评分、结肠长度及结肠黏膜损伤指数（colon mucosa damage index，CMDI）评分；苏木素-伊红（hematoxylin-eosin，HE）染色评估结肠组织病理损伤；ELISA检测血清中肿瘤坏死因子-α（tumor necrosis factor-α，TNF-α）、白细胞介素-6（interleukin-6，IL-6）和IL-1β水平；免疫组化检测结肠组织自噬相关16样蛋白1（autophagy related protein 16 like protein 1，ATG16L1）和GSDMD蛋白表达；Western blotting检测结肠组织自噬相关蛋白[Beclin-1、微管相关蛋白轻链3B（microtubule-associated protein light chain 3B，LC3B）、ATG16L1、p62]及焦亡通路相关蛋白（NLRP3、Caspase-1、GSDMD）的表达。结果 与模型组比较，Sch B显著改善UC大鼠体质量下降、便血等症状，降低DAI及CMDI评分（P＜0.05、0.01），增加结肠长度（P＜0.05、0.01），减轻结肠黏膜充血水肿、溃疡形成及炎症细胞浸润（P＜0.05、0.01），降低血清IL-6、TNF-α和IL-1β水平（P＜0.05、0.01），上调结肠组织Beclin-1蛋白表达并升高LC3-Ⅱ/Ⅰ值（P＜0.01），下调ATG16L1、p62、NLRP3、Caspase-1和GSDMD蛋白表达（P＜0.05、0.01）。结论 Sch B对TNBS诱导的UC大鼠具有显著治疗作用，其机制可能与调节细胞自噬流稳态、抑制NLRP3/Caspase-1/GSDMD信号通路介导的结肠上皮细胞焦亡、减少促炎因子释放以减轻肠道炎症反应相关，自噬流的正常化可能是Sch B抑制结肠上皮细胞焦亡的重要调控环节。

Objective To investigate the therapeutic effect of schisandrin B (Sch B) on ulcerative colitis (UC) in rats induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS), and explore its molecular mechanism in alleviating pyroptosis of colonic epithelial cells by regulating autophagy-related proteins as well as NOD-like receptor thermal protein domain associated protein 3 (NLRP3)/cysteine-aspartic protease-1 (Caspase-1)/gasdermin D (GSDMD) signaling pathway. Methods SD rats were randomly divided into control group, model group, mesalazine (100 mg/kg) group, Sch B low-, medium- and high-dose (10, 20, 50 mg/kg) groups, with 10 rats in each group, half male and half female. A TNBS-induced UC model was constructed, after 14 consecutive days of administration, the general conditions of rats were observed. The disease activity index (DAI) score, colon length and colon mucosa damage index (CMDI) score were detected. Histopathological injury of colonic tissue was evaluated by hematoxylin-eosin (HE) staining. Levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1β in serum were measured by ELISA. The expressions of autophagy related protein 16 like protein 1 (ATG16L1) and GSDMD proteins in colonic tissue were detected by immunohistochemistry. Western blotting was performed to detect the expressions of autophagy-related proteins (Beclin-1, microtubule-associated protein light chain 3B (LC3B), ATG16L1, p62) and pyroptosis pathway-related proteins (NLRP3, Caspase-1, GSDMD) in colonic tissue. Results Compared with model group, Sch B significantly ameliorated body weight loss, hematochezia and other symptoms in UC rats, reduced DAI and CMDI scores (P < 0.05, 0.01), increased colon length (P < 0.05, 0.01), alleviated colonic mucosal congestion, edema, ulcer formation and inflammatory cell infiltration (P < 0.05, 0.01), decreased levels of IL-6, TNF-α and IL-1β in serum (P < 0.05, 0.01), upregulated Beclin-1 protein expression and LC3-Ⅱ/Ⅰ ratio in colonic tissue (P < 0.01), and downregulated ATG16L1, p62, NLRP3, Caspase-1, GSDMD protein expressions (P < 0.05, 0.01). Conclusion Sch B exerts a remarkable therapeutic effect on TNBS-induced UC in rats. Its mechanism may be associated with maintaining autophagy flux homeostasis, inhibiting colonic epithelial cell pyroptosis mediated by NLRP3/Caspase-1/GSDMD signaling pathway, reducing the release of pro-inflammatory factors and thereby alleviating intestinal inflammatory response. Normalization of autophagy flux may be a key regulatory link for Sch B to inhibit colonic epithelial cell pyroptosis.

R285.5

国家自然科学基金面上项目（81973625）；河南省科技研发计划联合基金资助项目（242301420114）；河南省科技攻关项目（232102311221，262102311235）；河南省中医药科学研究专项（2021JDZY066，2024ZY2011）