背景：炎症相关的 NLRP3/Caspase-1/GSDMD 介导的细胞焦亡参与溃疡性结肠炎 (UC) 的进展。据报道，β-谷甾醇 (SIT) 对实验性结肠炎具有抗炎作用，但 SIT 对细胞焦亡的调节尚不清楚。因此，本研究旨在明确 SIT 对葡聚糖硫酸钠 (DSS) 诱导的实验性 UC 大鼠和人上皮结直肠腺癌细胞 (Caco-2) 的保护和愈合作用，并探讨其影响的潜在机制。 UC 中 NLRP3/Caspase-1/GSDMD 介导的细胞焦亡。方法：采用口服4%DSS建立UC模型。结肠炎损伤后，动物接受为期 2 周的 SIT（剂量为 50、100 和 200 毫克/公斤）治疗。对于体外研究，我们在有或没有 SIT 的情况下暴露 Caco-2-50 mg/mL DSS（浓度为 8 和 16 μg/mL）。在体内评估疾病活动指数（DAI）和组织病理学损伤。在结肠组织中检测到核因子κB（NF-κB）信号轴的激活蛋白以及紧密连接相关蛋白的闭合小带-1（ZO-1）和occludin。采用酶联免疫吸附试验（ELISA）测定血清和细胞上清液中的TNF-α、IL-1β和IL-18。分析组织和细胞中 NLRP3/Caspase-1/GSDMD 介导的细胞焦亡信号通路激活的变化。结果：我们的研究结果表明，SIT 治疗可以保护大鼠免受体重和结肠长度的减少以及宏观损伤，从而减轻 4% DSS 诱导的 UC 的严重程度。 SIT 还减少血清和细胞上清液中促炎因子（TNF-α、IL-1β 和 IL-18）的产生。从机制上讲，SIT 下调结肠组织和 Caco-2 细胞中焦亡相关蛋白的表达水平，包括 Caspase-1、cleaved-Caspase-1、NLRP3、GSDMD 和 GSDMD-N。进一步分析表明，SIT 通过增强 ZO-1 和 occludin 的蛋白表达来维持结肠屏障的完整性。结论：我们证实 SIT 通过抑制 NLRP3/Caspase-1/GSDMD 介导的细胞焦亡和炎症反应，对 DSS 诱导的结肠炎损伤发挥保护和治疗作用。这些发现表明，SIT 可能是治疗 UC 的潜在药物。版权所有 © 2023 张、葛、季、李、张、王、张、张和陈。

Background: Inflammation-related NLRP3/Caspase-1/GSDMD-mediated pyroptosis is involved in the progression of ulcerative colitis (UC). β-sitosterol (SIT) was reported to have anti-inflammatory effects on experimental colitis, while the regulation of SIT on pyroptosis is unclear. Therefore, the present study aimed to define the protective and healing effects of SIT on dextran sulfate sodium (DSS)-induced experimental UC rats and human epithelial colorectal adenocarcinoma cells (Caco-2) and explore the underlying mechanisms that are responsible for its effects on NLRP3/Caspase-1/GSDMD-mediated pyroptosis in UC. Methods: UC model rats were established by oral 4% DSS. Following colitis injury, the animals received SIT (doses of 50, 100, and 200 mg/kg) treatment for 2 weeks. For in vitro study, we exposed Caco-2-50 mg/mL DSS with or without SIT (concentrations of 8 and 16 μg/mL). Disease activity index (DAI) and histopathological injury were assessed in vivo. Activation proteins of nuclear factor kappa B (NF-κB) signaling axis, and tight junction-related proteins of zonula occludens-1 (ZO-1) and occludin were detected in colon tissues. TNF-α, IL-1β, and IL-18 in serum and cell supernatant were measured by enzyme-linked immunosorbent assay (ELISA). Changes in NLRP3/Caspase-1/GSDMD-mediated pyroptosis signaling pathway activation were analyzed both in tissues and cells. Results: Our findings suggested that SIT treatment attenuated the severity of 4% DSS-induced UC by protecting rats from weight and colon length loss, and macroscopic damage. SIT also reduced proinflammatory factors production (TNF-α, IL-1β, and IL-18) in serum and cell supernatant. Mechanistically, SIT downregulated the expression levels of pyroptosis-related proteins including Caspase-1, cleaved-Caspase-1, NLRP3, GSDMD, and GSDMD-N in colon tissues and Caco-2 cells. Further analysis indicated that SIT maintained the colonic barrier integrity by enhancing the protein expression of ZO-1 and occludin. Conclusion: We confirmed that SIT exerts protective and therapeutic effects on DSS-induced colitis injury by suppressing NLRP3/Caspase-1/GSDMD-mediated pyroptosis and inflammation response. These findings demonstrated that SIT could be a potential medication for UC treatment.Copyright © 2023 Zhang, Ge, Ji, Li, Zhang, Wang, Zhang, Zhang and Chen.