基于中性粒细胞胞外诱捕网（NETs）探讨白及对溃疡性结肠炎（UC）大鼠肠黏膜屏障的修复作用及 机制。方法 将 48 只 SD 大鼠随机分为正常组、模型组、柳氮磺胺吡啶组（0.3 g·kg-1 ）及白及低、中、高剂量 组（0.3、0.6、1.2 g·kg-1 ），每组 8 只。采用 2，4，6-三硝基苯磺酸（TNBS）-乙醇灌肠法复制 UC 大鼠模型，造模 成功后按照设定剂量灌胃给药，每日 1 次，连续灌胃给药 21 d。在给药干预的第 1、11、21 天进行疾病活动指 数（DAI）评分；采用 HE 染色法观察大鼠结肠组织病理变化；ELISA 法检测大鼠血清中肿瘤坏死因子 α（TNF-α） 和白细胞介素 1β（IL-1β）含量；Western Blot 法及免疫组化法检测大鼠结肠组织中 NETs 相关蛋白髓过氧化物酶 （MPO）、中性粒细胞弹性蛋白酶（NE）、血管内皮生长因子（VEGF）以及紧密连接（TJs）相关蛋白封闭蛋白 2 （CLDN2）、闭锁小带蛋白 1（ZO-1）的表达水平。结果 与正常组比较，模型组大鼠 DAI 明显升高（P＜0.05）； 结肠组织黏膜层出现大面积变性坏死且肠腺结构消失，大量炎性细胞浸润，累及黏膜下层、肌层和浆膜层，病 理评分明显升高（P＜0.05）；血清 TNF-α、IL-1β 水平明显升高（P＜0.05）；结肠组织中 MPO、NE、VEGF、 CLDN2 蛋白表达明显升高（P＜0.05），ZO-1 蛋白表达明显降低（P＜0.05）。与模型组比较，各给药组大鼠的 DAI 均明显降低（P＜0.05）；柳氮磺胺吡啶组和白及中、高剂量组大鼠结肠肠腺结构完整清晰，黏膜未见明显 变性及坏死，可见少量炎性细胞浸润，病理评分明显降低（P＜0.05）；血清 TNF-α、IL-1β 水平明显降低（P＜ 0.05）；结肠组织中 MPO、NE、VEGF、CLDN2 蛋白表达明显降低（P＜0.05），ZO-1 表达明显升高（P＜0.05）。 结论 白及可能通过调控 NETs 激活及 TJs 相关蛋白表达，降低血清炎症因子水平，从而修复肠道黏膜屏障， 发挥治疗 UC 的作用。

To investigate the repair effect of Bletillae Rhizoma on intestinal mucosal barrier in rats with ulcerative colitis （UC） based on neutrophil extracellular traps （NETs） . Methods Forty-eight SD rats were randomly divided into normal group， model group， Sulfasalazine group （0.3 g·kg-1）， Bletillae Rhizoma low-， medium- and high-dose groups （0.3， 0.6， 1.2 g · kg-1）， with 8 rats in each group. The UC rat model was established by 2，4，6-trinitrobenzene sulfonic acid （TNBS）- ethanol enema. After successful modeling， the corresponding drugs were given by gavage for 21 days. The normal group and the model group were given equal volume of normal saline by gavage. The disease activity index （DAI） was evaluated on the first， eleventh and twenty-first day of administration. Hematoxylin-eosin （HE） staining was used to observe the colon pathology of rats in each group. The levels of tumor necrosis factor- α （TNF-α） and interleukin-1β （IL-1β） in serum were measured by enzyme-linked immunosorbent assay （ELISA） . Immunohistochemistry （IHC） and Western Blot （WB） were used to detect the expressions of NETs-related proteins myeloperoxidase （MPO），neutrophil elastase （NE），vascular endothelial growth factor（VEGF），tight junction（TJs） -related proteins claudin-2（CLDN2） and zonula occludens-1 （ZO-1） in colon tissue. Results Compared with the normal group，the DAI of rats in the model group was significantly up-regulated （P＜0.05）， and the pathological conditions such as mucosal necrosis and inflammatory infiltration appeared in the colon tissue. The contents of TNF-α and IL-1β in serum were significantly increased （P＜0.05）， and the protein expressions of MPO， NE， VEGF and CLDN2 in colon tissue were significantly increased （P＜0.05）， and the protein expression of ZO-1 was significantly decreased （P＜0.05） . Compared with the model group， the DAI of rats in each administration group was significantly decreased （P＜ 0.05） . The colonic intestinal gland structure of rats in the Sulfasalazine group and the medium- and high- dose groups of Bletillae Rhizoma was complete and clear, there was no obvious degeneration and necrosis of the mucosa, a small amount of inflammatory cell infiltration was observed， and the pathological score was significantly decreased （P＜0.05） . The levels of serum TNF - α and IL-1β were significantly decreased （P＜0.05） . The protein expressions of MPO， NE， VEGF and CLDN2 in the colon were significantly decreased （P＜0.05）， and the expression of ZO-1 was significantly increased （P＜0.05） . Conclusion Bletillae Rhizoma may regulate the expression of TJs-related proteins by regulating the production of NETs， thereby improving the intestinal mucosal barrier injury and inflammatory infiltration in rats to play a therapeutic role in UC rats

R285.5

国家自然科学基金后补助资金科研创新探索专项（2019YFC171250504）；贵州省教育厅滚动支持省属高校科研平台团队项目[黔教技 （2022）023号]。