慢性束缚肠道应激损伤小鼠模型的构建与评价

Construction and evaluation of a mouse model of chronic restraint intestinal stress injury

目的结合社会心理应激导致炎症性肠病、肠易激综合征等一系列疾病的特点,建立实验性慢性束缚小鼠肠道应激损伤模型,为探讨慢性束缚应激诱导胃肠病的致病机制以及防治措施奠定基础。方法18只雄性SPF级BALB/c小鼠,适应7 d后,根据体重按随机数字表法分为2组,对照组及慢性束缚应激组。对小鼠进行束缚应激,每天3 h,连续束缚14 d,建立肠道损伤模型。通过观察体重、肠道组织病理形态变化、检测紧密连接蛋白表达、肠上皮细胞凋亡以及炎症细胞因子mRNA表达水平等指标对模型进行评价。结果慢性束缚应激14 d,小鼠表现为体重减轻,十二指肠绒毛高度变短、隐窝结构异常、绒毛/隐窝比下降;结肠黏膜炎性细胞浸润、隐窝结构不规则。蛋白免疫印迹、免疫组化和免疫荧光染色结果显示,慢性束缚应激后小鼠十二指肠和结肠紧密连接蛋白Occludin、Claudin-1表达显著下降(P<0.05);肠上皮细胞凋亡蛋白Cleaved-Caspase-3的表达显著增加(P<0.05)。此外,肠道炎症因子和趋化因子mRNA表达结果显示,慢性束缚应激14 d显著提高了小鼠十二指肠IL-1β、IL-6、MCP-1、TNF-α、IL-10基因的表达(P<0.05);慢性束缚应激14 d显著提高了小鼠结肠IL-1β、IL-6、MCP-1的表达(P<0.001)。结论利用小鼠行为限制装置对小鼠连续束缚14 d,导致应激小鼠肠道组织结构异常、肠屏障功能障碍、肠上皮细胞凋亡,引发肠道炎症反应,表明慢性束缚应激肠道损伤小鼠模型构建成功。

Objective Given that psychosocial stress can contribute to a series of diseases,such as inflammatory bowel disease and irritable bowel syndrome,we aimed to establish an experimental chronic restraint mouse intestinal stress injury model as a basis for exploring the pathogenic mechanism of chronic restraint stress-induced gastrointestinal diseases,and for developing preventive and curative measures.Methods Eighteen male SPF-grade BALB/c mice were acclimatized for 7 days and then divided into a control group and a chronic restraint stress group according to body weight,using a randomized numerical table method.The mice were subjected to restraint stress for 3 hours per day for 14 days to establish an intestinal injury model.The model was evaluated by observing body weight,pathological changes in intestinal histomorphology,expression of tight junction proteins,apoptosis of intestinal epithelial cells,and mRNA expression levels of inflammatory cytokines.Results After 14 days of chronic restraint stress,model mice showed weight loss,shortened duodenal villus height,abnormal crypt structure,a decreased villus/crypt ratio,colonic mucosal inflammatory cell infiltration,and irregular crypt structure.Protein immunoblotting,immunohistochemistry,and immunofluorescence staining showed that the expression levels of the duodenal and colonic tight junction proteins Occludin and Claudin-1 were significantly decreased in mice after chronic restraint stress(P<0.05),while expression levels of the apoptotic protein cleaved-caspase-3 in intestinal epithelial cells were significantly increased(P<0.05).Regarding the mRNA expression levels of intestinal inflammatory factors and chemokines,chronic restraint stress for 14 days significantly increased the gene expression levels of interleukin(IL)-1β,IL-6,monocyte chemoattractant protein-1(MCP-1),tumor necrosis factor-α,and IL-10 in the duodenum of mice(P<0.05),and significantly increased the gene expression levels of IL-1β,IL-6,and MCP-1 in the colon(P<0.001).Conclusions The use of a behavioral restriction device to restrain mice continuously for 14 days led to abnormal intestinal tissue structure,intestinal barrier dysfunction,and intestinal epithelial cell apoptosis,and triggered an intestinal inflammatory response in the stressed mice,indicating successful establishment of a mouse model of intestinal injury by chronic restraint stress.