[关键词]
[摘要]
目的 基于白细胞介素 17A(IL-17A)/核因子 κB(NF-κB)/丝裂原活化蛋白激酶(MAPK)信号通路探讨薏 苡素对溃疡性结肠炎(UC)小鼠的作用及机制。方法 将 C57BL/6J 小鼠随机分为正常组、模型组、美沙拉嗪 (600 mg·kg -1 )组及薏苡素低(25 mg·kg -1 )、高(50 mg·kg -1 )剂量组,每组 10 只。正常组饮用蒸馏水,其余各组 在实验的第 1、4、7 周给予 2%DSS 溶液自由饮用。第 4 周开始按照上述剂量灌胃给药,正常组及模型组给予 等量 0.5%CMC-Na 溶液(10 mL·kg -1 )灌胃,每日 1 次,连续给药 4 周。观察并记录小鼠的一般情况,并进行粪 便隐血检测,计算疾病活动指数(DAI)、体质量下降率;采用 ELISA 法检测血清白细胞介素 6(IL-6)、IL-8、 IL-1β、肿瘤坏死因子 α(TNF-α)、IL-10、脂多糖(LPS)和髓过氧化物酶(MPO)水平;苏木精-伊红(HE)、阿 尔新蓝-过碘酸-雪夫(AB-PAS)染色法观察结肠组织病理变化及杯状细胞数量;麦胚凝集素(WGA)染色法观察 结肠组织中黏蛋白分泌情况;透射电镜观察结肠组织超微结构;qRT-PCR 法检测结肠组织 IL-17A、IL-17RA、 Act1、TRAF6、NF-κB、IKBα、p38 MAPK mRNA 表达水平;Western Blot 法检测结肠组织 IL-17A、IL-17RA、 Act1、TRAF6、NF-κB、IKBα、p38 MAPK 蛋白表达水平。结果 与正常组比较,模型组小鼠精神萎靡,动作 迟缓,毛色暗淡无光泽,身体蜷缩,逐渐出现腹泻、脓血便等情况;小鼠体质量显著下降(P<0.01),结肠长 度显著缩短(P<0.01),DAI 评分显著增加(P<0.01);血清 IL-6、IL-8、IL-1β、TNF-α、LPS、MPO 水平均 显著升高(P<0.01),IL-10 水平显著降低(P<0.01);结肠组织上皮损伤,隐窝结构紊乱,黏膜及黏膜下层弥 漫性炎症细胞浸润,病理评分显著升高(P<0.01);结肠组织中的杯状细胞数量减少且较分散,杯状细胞面积 占比显著降低(P<0.01),黏蛋白分泌显著减少(P<0.01);结肠组织黏膜上皮细胞排列紊乱,微绒毛排列不规 则,细胞中出现较多空泡,线粒体肿胀,线粒体嵴结构损伤,细胞连接增宽;结肠组织 IL-17A、IL-17RA、 Act1、TRAF6、NF-κB、p38 MAPK mRNA 表达水平显著升高(P<0.01),IKBα mRNA 表达水平显著降低(P< 0.01);结肠组织 IL-17A、IL-17RA、Act1、TRAF6、p-NF-κB/ NF-κB、p-IKBα/ IKBα、p-p38 MAPK/ p38 MAPK 蛋白表达水平均显著升高(P<0.01)。与模型组比较,各给药组小鼠的精神状态均有所好转,毛色光泽 度得到改善,腹泻及脓血便情况减少;小鼠体质量及结肠长度显著增加(P<0.05,P<0.01),DAI 评分显著降 低(P<0.01);血清 IL-6、IL-8、IL-1β、TNF-α、LPS、MPO 水平显著降低(P<0.05,P<0.01),IL-10 水平 显著升高(P<0.01);结肠组织上皮及隐窝结构损伤均有所恢复,炎性浸润面积减小、程度减轻,病理评分显 著降低(P<0.05,P<0.01);结肠组织中杯状细胞明显增多,杯状细胞面积占比显著升高(P<0.01),黏蛋白 分泌显著增多(P<0.05,P<0.01);结肠黏膜上皮细胞排列较为整齐,微绒毛排列较为规则,细胞中空泡减 少,线粒体肿胀程度减轻,嵴结构有所恢复,细胞连接变窄;结肠组织中 IL-17A、IL-17RA、Act1、TRAF6、 NF-κB、p38 MAPK mRNA 表达水平显著降低(P<0.05,P<0.01),IKBα mRNA 表达水平显著升高(P<0.01); 薏苡素高、低剂量组结肠组织 IL-17A、IL-17RA、Act1、TRAF6、p-NF-κB/ NF-κB、p-IKBα/ IKBα、p-p38 MAPK/p38 MAPK 蛋白表达水平均显著降低(P<0.05,P<0.01)。结论 薏苡素能够修复 UC 小鼠的肠黏膜损 伤,抑制炎症细胞浸润,保护结肠组织结构完整,调节炎症相关因子水平,其作用机制可能与抑制 IL-17A/ NF-κB/MAPK信号通路有关。
[Key word]
[Abstract]
Objective To investigate the effect and mechanism of coixol on ulcerative colitis (UC) in mice based on the interleukin-17A (IL-17A)-nuclear factor-κB (NF-κB)/mitogen-activated protein kinase (MAPK) signaling pathway. Methods C57BL/6J mice were randomly divided into normal group,model group,mesalazine group (600 mg·kg -1 ), and coixol low-dose (25 mg·kg -1 ) and high-dose (50 mg·kg -1 ) groups,with 10 mice per group. The normal group was given distilled water,while the other groups received 2%DSS solution ad libitum on weeks 1,4,and 7. From week 4, the drug groups were administered by gavage at the above doses,while the normal and model groups received 0.5% CMC-Na solution (10 mg·kg -1 ) once daily for 4 weeks. General conditions were observed, fecal occult blood was detected,and disease activity index (DAI) and body mass loss rate were calculated. Serum levels of IL-6,IL-8,IL-1β, TNF-α,IL-10,lipopolysaccharide (LPS),and myeloperoxidase (MPO) were measured by ELISA. Hematoxylin- eosin (HE) and Alcian blue-periodic acid-Schiff (AB-PAS) staining were used to observe colonic pathological changes and goblet cell count. Wheat germ agglutinin (WGA) staining was applied to assess mucin secretion. Transmission electron microscopy was used to observe colonic ultrastructure. qRT-PCR and Western Blot were retrospectively employed to detect mRNA and protein expression of IL-17A,IL-17RA,Act1,TRAF6,NF-κB,IKBα,and p38 MAPK in colonic tissue. Results Compared with the normal group, the model group showed lethargy, sluggish movement,dull fur,hunched posture,diarrhea,and bloody stools;significant decreases in body mass and colon length (P<0.01),increased DAI score (P<0.01);elevated serum IL-6,IL-8,IL-1β,TNF-α,LPS,and MPO levels (P<0.01),decreased IL-10 (P<0.01);epithelial damage,crypt distortion,diffuse inflammatory infiltration in mucosa and submucosa, and increased pathological score (P<0.01); reduced and scattered goblet cells with decreased area proportion (P<0.01) and mucin secretion (P<0.01); disordered epithelial cell arrangement, irregular microvilli, vacuolation, mitochondrial swelling, cristae damage, and widened intercellular junctions; upregulated mRNA expression of IL-17A, IL-17RA, Act1, TRAF6, NF- κB, and p38 MAPK (P<0.01), downregulated IKBα mRNA (P<0.01);increased protein expression of IL-17A,IL-17RA,Act1,TRAF6,p-NF-κB/ NF-κB,p-IKBα/IKBα,and p-p38 MAPK/p38 MAPK (P<0.01). Compared with the model group,all treatment groups showed improved mental state,glossier fur,reduced diarrhea and bloody stools;increased body mass (P< 0.05,P<0.01) and colon length (P<0.01),decreased DAI score (P<0.01);reduced serum IL-6,IL-8,IL-1β, TNF-α,LPS,and MPO (P<0.05,P<0.01),increased IL-10 (P<0.01);restored epithelial and crypt structure, reduced inflammatory infiltration and pathological score (P<0.05,P<0.01);increased goblet cell count and area proportion (P<0.01),enhanced mucin secretion (P<0.05,P<0.01);improved epithelial cell alignment,regular microvilli, reduced vacuolation, alleviated mitochondrial swelling, restored cristae structure, and narrowed intercellular junctions;downregulated mRNA expression of IL-17A,IL-17RA,Act1,TRAF6,NF-κB,and p38 MAPK (P<0.05,P<0.01),upregulated IKBα mRNA (P<0.01);decreased protein expression of IL-17A,IL-17RA, Act1, TRAF6, p-NF- κB/NF- κB, p-IKBα/IKBα, and p-p38 MAPK/p38 MAPK (P<0.05, P<0.01). Conclusion Coixol can repair intestinal mucosal damage, inhibit inflammatory cell infiltration, protect colonic structural integrity, and regulate inflammatory factors in UC mice,potentially by suppressing the IL-17A/NF-κB/ MAPK signaling pathway.
[中图分类号]
R285.5
[基金项目]
国家自然科学基金青年基金项目(82003913);河北省自然科学基金项目(H2024206502);河北省教育厅科技项目(BJK2024082)。