Abstract: Objective　To investigate the effects of Coptis chinensis extract  (CE) on colonic ulcerative mucosal injury in rats and explore the underlying mechanisms. Methods　The formal experiment was conducted on March 5, 2024, in the animal laboratory of the Jiangxi University of Traditional Chinese Medicine. 70 rats were divided into blank group, UC model group, CE (low, medium, and high) dose group (given 0.4, 0.6, and 0.8 g/kg CE by gavage), mesalazine group (given 0.36 g/kg mesalazine by gavage), and CE+JAK2 activator group (given 0.8 g/kg CE+1 mg/kg coumermycin A1 by gavage), with 10 rats in each group. A 3% dextran sulfate sodium (DSS) solution was provided for free drinking for 7 days to construct the UC rat model. All rats were given intragastric administration once a day for 7 days. During the experiment, the health status of the rats was observed, and the disease activity index (DAI) score was calculated; the length of the colon tissue was measured; HE staining was used to observe pathological changes in the colon tissue; RT-qPCR was employed to detect the expression of pro-inflammatory cytokines interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) mRNA in the colon; ELISA was used to measure the levels of inflammatory factors in the colon tissue; and Western blot analysis was performed to detect the expression of proteins related to the JAK2/STAT3 signaling pathway [Janus kinase 2 (JAK2), pJAK2, signal transducer and activator of transcription 3 (STAT3), and p-STAT3]. Statistical analysis was conducted using t test and F test. Result　Compared to the blank group, the model group exhibited significant pathological damage in the colon tissue, poor mental state, and a marked reduction in colon length (P<0.05). Body weight and levels of IL-4 and IL-10 decreased significantly (all P<0.05), while the disease activity index (DAI) score, histopathological score, and expression of IL-1β, IL-6, and TNF-α mRNA in the colon, along with the expression of proteins related to the JAK2/STAT3 signaling pathway, increased significantly (all P<0.05).In comparison to the model group, the CE gradient dose groups and the mesalazine group showed improvements in mental state and pathological damage in the colon tissue. Body weight and levels of IL-4 and IL-10 in the colon tissue significantly increased (all P<0.05), while DAI scores, histopathological scores, levels of IL-1β, IL-6, TNF-α, and the expression of JAK2, phosphorylated JAK2 (p-JAK2), STAT3, and phosphorylated STAT3 (p-STAT3) proteins decreased significantly (all P<0.05). The colon length also increased significantly (P<0.05) and was positively correlated with the dosage. Furthermore, the JAK2 activator was found to activate the JAK2/STAT3 signaling pathway, diminishing the therapeutic effect of CE on intestinal mucosal injury in the UC rats. Conclusion　CE can improve intestinal damage to ulcerative colitis in rats, and its mechanism of action may be to inhibit the activation of JAK2/STAT3 signaling pathway, reduce the release of pro-inflammatory factors, and enhance the barrier function of colon mucosa.

Key words: Ulcerative colitis, Coptis chinensis extract, JAK2/STAT3 signaling pathway, Animal  , experiment

摘要： 目的　探究黄连提取物（Coptis chinensis extract，CE）对大鼠溃疡性结肠炎（ulcerative colitis，UC）黏膜组织损伤的影响，并探讨其相关机制。方法　本次正式实验于2024年3月5日在江西中医药大学实验动物科技中心内进行。将70只大鼠分为空白组、UC模型组、CE梯度（低、中、高）剂量组（0.4、0.6、0.8 g/kg CE灌胃）、美沙拉嗪组（0.36 g/kg美沙拉嗪溶液灌胃）、CE+Janus激酶2（JAK2）激活剂组（0.8 g/kg CE+1 mg/kg香豆霉素A1灌胃），每组10只。采用3%葡聚糖硫酸钠（dextran sulfact sodium，DSS）水溶液自由饮用法7 d，构建UC大鼠模型。所有大鼠均每日灌胃1次，持续7 d。实验期间观察大鼠健康状况，并计算疾病活动指数（disease activity index，DAI）评分；测量大鼠结肠组织长度；采用苏木精-伊红（HE）染色技术，观察大鼠结肠组织病理学改变情况；运用RT-qPCR技术检测大鼠结肠中促炎性细胞因子白细胞介素1β（IL-1β）、IL-6及肿瘤坏死因子α（TNF-α）mRNA的表达水平；利用酶联免疫吸附分析（ELISA）对大鼠结肠组织中炎症因子水平进行检测；Western blot 法检测结肠组织中JAK2/信号转导与转录激活子3（STAT3）信号通路相关蛋白［JAK2、磷酸化STAT3（p-STAT3）、STAT3、磷酸化STAT3（p-STAT3）蛋白］的表达水平。采用t、F检验进行统计分析。结果　与空白组相比，模型组大鼠结肠组织出现显著的病理损伤，精神状态差，结肠长度明显缩短（P<0.05），体质量及IL-4、IL-10水平均下降（均P<0.05），DAI评分、组织病理学评分以及结肠组织中IL-1β、IL-6、TNF-α mRNA表达水平和JAK2/STAT3信号通路相关蛋白表达水平均明显上升（均P<0.05）。与模型组相比，CE梯度剂量组及美沙拉嗪组大鼠的精神状态与结肠组织病理损伤均有所改善；体质量及结肠组织中IL-4、IL-10水平均显著升高（均P<0.05），DAI评分、组织病理学评分和结肠组织中IL-1β、IL-6、TNF-α mRNA的表达水平及JAK2、p-JAK2、STAT3、p-STAT3蛋白表达水平均明显下降（均P<0.05），结肠长度明显增加（P<0.05），且与CE剂量呈正相关。此外，JAK2激活剂可激活JAK2/STAT3信号通路，减弱CE对UC大鼠肠道黏膜损伤的治疗效果。结论　CE可改善大鼠溃疡性结肠炎的肠道损伤，其作用机制可能与抑制JAK2/STAT3信号通路的活化、减少促炎性细胞因子释放有关，进而增强结肠黏膜的屏障功能。

关键词: 溃疡性结肠炎, 黄连提取物, JAK2/STAT3信号通路, 动物实验