氯化两面针碱对小鼠溃疡性结肠炎的干预作用及其机制*

目的:探讨氯化两面针碱(NC)通过靶向miR-31对葡聚糖硫酸钠(DSS)诱发小鼠结肠炎的保护作用及其机制。方法:用1%DSS诱发小鼠溃疡性结肠炎(UC)。30只雄性C57BL/6小鼠随机分为正常对照组(Control)(n=7),DSS组(n=8),DSS+NC组(7.27 mg/kg)(n=8)和NC组(n=7),饮水给予DSS,灌胃给予氯化两面针碱。造模周期为3周,分别为Control组和NC组每天饮用无菌水,DSS组和DSS+NC组第一周饮用1% DSS水,第2周正常饮水,第3周1% DSS水。造模最后一周给予Control组和DSS组小鼠0.5% 羧甲基纤维素钠(CMC-Na)灌胃,DSS+NC组和NC组给予NC灌胃。造模完成后,观察小鼠结肠炎相关的疾病活动指数(DAI),HE染色进行结肠组织病理评分,qPCR检测小鼠结肠组织miR-31的表达水平,Western blot检测小鼠结肠组织炎症蛋白NF-κB和COX-2的表达情况。结果:①与DSS组相比,DSS+NC组的 DAI 显著降低(P＜0.01),结肠病理损伤明显改善;②与Control组相比,DSS组小鼠结肠组织miR-31表达显著升高(P＜0.01),DSS+NC组miR-31的表达水平显著低于DSS组(P＜0.05);③与DSS组相比,DSS+NC组中的炎症蛋白NF-κB和COX-2表达水平显著下降(P＜0.05)。结论:氯化两面针碱对DSS诱导的小鼠溃疡性结肠炎有明显的治疗作用,其抗炎机制与下调miR-31的表达有关。

Effects of nitidine chloride on ulcerative colitis in mice and its mechanism

Objective: To investigate the protective effects of nitidine chloride (NC) on dextran sodium sulfate (DSS) - induced ulcerative colitis (UC) in mice by targeting miR-31 and its underlying mechanisms. Methods: DSS at the concentration of 1% was used to induce UC in mice. Thirty C57BL/6 male mice were randomly divided into four groups: normal control group (n=7), DSS group (n=8), DSS + NC group (7.27 mg/kg) (n=8) and NC group (n=7). DSS was added in drinking water, and NC was administrated by gavage. The period of modeling lasted for 3 weeks. The control group and NC group drank sterile water every day, DSS group and DSS + NC group drank 1% DSS water in the first week, normal water in the second week and 1% DSS water in the third week. In the last week of modeling, mice in control group and DSS group were given 0.5% CMC-Na by gavage, while mice in DSS + NC group and NC group were given NC by gavage. After the establishment of the model, the disease activity index (DAI) related to colitis was observed, the pathological score of colon tissue was evaluated by HE staining, the expression level of miR-31 in colon tissue was detected by qPCR, and the protein expressions of NF -κ B and COX-2 in colon tissue were detected by Western blot. Results: ① Compared with DSS group, the DAI in the DSS + NC group was decreased (P＜0.01). The colonic pathological injury was obviously ameliorated after treated by NC. ② Compared with normal control group, the expression of miR-31 in colonic tissue of DSS group was increased significantly(P＜0.01), compared with DSS group, the expression of miR-31 was decreased after treatment with NC(P＜ 0.05). ③ Compared with DSS group, the levels of inflammatory protein NF-κB and COX-2 in DSS + NC group was decreased significantly (P＜0.05). Conclusion: Nitidine chloride has obvious therapeutic effects on DSS induced mouse colitis, and its anti-inflammatory mechanism is related to the down-regulation of miR-31 expression.