乙酸联合束缚应激诱导腹泻型肠易激综合征小鼠模型的制备

Preparation of a mouse model of irritable bowel syndrome with diarrhea induced by acetic acid combined with restraint stress

目的采用3%乙酸(acetic acid,AA)直肠灌注联合束缚应激的方法制备腹泻型肠易激综合征(irritable bowel syndrome with diarrhea,IBS-D)小鼠模型,并评价模型的可行性。方法雄性C57BL/6J小鼠45只,均分为健康对照组(C组)、3%乙酸组(A组)、3%乙酸+束缚组(A+R组)。比较各组小鼠干预前后体重变化和存活情况,以及干预后粪便含水量、全肠道转运时间、内脏痛阈值,比较两种造模方法的优劣。观察C组和A+R组的结肠病理形态的变化,采用FD4渗透实验评价小鼠肠道粘膜完整性,ELISA法检测血清5-HT和TNF-α的含量,免疫组化法检测结肠组织中5-HTR3A的表达,明确该造模方法的病理变化特征。结果与C组相比,A+R组的内脏痛阈值、粪便含水量显著升高(P<0.001);全肠道转运时间明显缩短(P<0.05),而A组内脏痛阈值和粪便含水量虽然也明显降低(P<0.05),但全肠道转运时间仅有变化的趋势,无显著性差异(P>0.05)。A+R组血浆中FD4含量显著增加(P<0.001),血清中5-HT和TNF-α含量明显增加(P<0.05),结肠组织中5-HTR3A表达量也显著增加(P<0.001)。结论与3%乙酸灌肠相比,3%乙酸灌肠联合束缚应激的方式能较好地模拟IBS-D患者的肠道局部相关症状,并能模拟相关的病理改变。

Objective To prepare an irritable bowel syndrome with diarrhea(IBS-D)mouse model by rectal perfusion with acetic acid combined with restraint stress,and to evaluate the feasibility of the model.Methods Forty-five male C57 BL/6 J mice were divided into a healthy control group(Group C),3%acetic acid group(Group A),and 3%acetic acid combined with restraint stress group(Group A+R).The body weights and survival rates of the groups were compared before and after intervention,and the fecal water content,total intestinal transport time,and colonic pain threshold of each group were compared after intervention.The advantages and disadvantages of the two modeling method were then assessed.Pathological changes to the colons in Group C and Group A+R were observed.Fluorescein isothiocyanate-dextran 4(FD4)was used to evaluate the integrity of the intestinal mucosa of mice in Group C,and the model with the best success rate was determined.To clarify the pathological characteristics of this modeling method,the serum contents of 5-HT and TNF-αwere determined by ELISA,and the expression of 5-HTR3 A in colon tissue was detected with immunohistochemistry.Results Compared with Group C,Group A+R had a significantly increased colonic pain threshold and fecal water content(P<0.001).The total intestinal transport time was significantly shortened(P<0.05),and the colonic pain threshold and fecal water content were significantly decreased in Group A(P<0.001);however,there was no significant difference in intestinal transport time between the groups(P>0.05).Compared with Group C,Group A+C showed a significant increase in the content of plasma FD4 and serum 5-HT and TNF-αand the expression of 5-HTR3 A in colon tissues(P<0.05).Conclusions Compared with 3%acetic acid,treatment with 3%acetic acid combined with restraint stress more convincingly simulated the local intestinal symptoms and related pathological changes seen in IBS-D patients.