miR-21介导肠上皮细胞凋亡维持肠道稳态参与溃疡性结肠炎相关癌变研究  

miR-21 mediates intestinal epithelial cell apoptosis and maintains intestinal homeostasis in the onset of ulcerative colitis associated carcinogenesis

作　　者：周海新[1] 方健松 张涛[2] 马媛萍 黄晓燕[3] 

机构地区：[1]海南省中医院消化科,海口570203 [2]广西中医药大学附属瑞康医院消化科,南宁530011 [3]广西中医药大学第一附属医院,南宁530011

出　　处：《安徽医科大学学报》2017年第4期523-527,共5页Acta Universitatis Medicinalis Anhui

基　　金：海南省卫生计生行业科研项目(编号:14A210219);广西自然科学基金项目(编号:2013GXNSFAA019116)

摘　　要：目的观察溃结癌变小鼠结肠黏膜miR-21、Caspase-8、肠上皮细胞凋亡及β-防御素表达,探讨溃结相关癌变的可能发病机制。方法 40只雄性清洁级Balb-c小鼠按体质量随机分2组即正常组和模型组,其中正常组10只,模型组30只。采用二甲肼/葡聚糖硫酸钠(DMH/DSS)复合法制备溃结癌变相关模型,造模30周结束后处死全部小鼠,应用光镜检测小鼠结肠黏膜组织形态学变化,电镜检测超微组织结构及上皮细胞凋亡变化;应用现代分子生物学技术检测miR-21、Caspase-8及β-防御素表达变化。结果与正常组比较,溃结相关癌变小鼠结肠黏膜光镜下见结肠黏膜不同程度缺损,表面渗出及坏死物,细胞形态异型,呈浸润癌改变;电镜下见肠黏膜层上皮细胞表面微绒毛稀疏,长短不一,细胞连接间隙增宽,见大量上皮细胞凋亡小体及细胞自噬,线粒体肿胀,结构不清,嵴结构消失,造模成功率约70%。与正常组比较,溃结癌变小鼠结肠黏膜miR-21、Caspase-8、β-防御素蛋白及mRNA表达均呈明显上升趋势,差异有统计学意义(P<0.05)。结论溃结相关癌变的发生及发展可能是由于溃疡性结肠炎(UC)炎症持续,诱导miR-21、Caspase-8及β-防御素表达增加,破坏肠道免疫平衡,导致肠黏膜通透性增加,肠上皮细胞凋亡凋亡/自噬加剧,造成恶性循环,进一步破坏肠道稳态,上皮细胞异型增生,甚则癌变。Objective To investigate the pathogenesis of ulcerative colitis associated carcinogenesis（UCAC） by observing the expression of miR-21,caspase-8,β-defensin and intestinal epithelial cell（IEC） apoptosis. Methods Forty male clean grade BALB/c rats were randomly divided into normal group and model group by wight. UCAC model was made by intraperitoneal injection with dimethylhydrazine（DMH） and free drinking dextran sulfacte sodium（DSS）. After thirty weeks,all rats were killed. The colon morphological changes were assayed by light microscope. The ultra microstructure and eithelial cell apoptosis were detected by electron microscope. The expression of miR-21,caspase-8 and β-defensin were detected by Real-time PCR and Western blot. Results Under light microscope,the major pathological changes of colon mucosa in model group were as follows： different level defect of colonic mucosa,surface exudation,necrosis,atypical cells and invasive cancer changes. Electron microscope results reveal that intestinal mucosal epithelial cell layer of microvilli on the surface of different lengths and cell junction gap widened in model group. Meanwhile,there were a lot of epithelial cells apoptosis and autophagy,mitochondrial swelling,cristae disappeared structure in model group. Compared with normal group,the expression of miR-21,caspase-8 and β-defensin increased significantly in model group（P〈0. 05）. Conclusion The occurrence and development of UCAC may be due to persistent inflammation in colon which led to high-expression of miR-21,caspase-8 and β-defensin and destruction of the intestinal immune balance,aggravation of IEC apoptosis/autophagy. These changes may be related to cause a vicious spiral,further damage to intestinal homeostasis,epithelial dysplasia,even carcinogenesis.

关 键 词：MIR-21 肠上皮细胞凋亡 肠道稳态 溃结相关癌变 

分 类 号：R574.62[医药卫生—消化系统]