3种浓度葡聚糖硫酸钠诱导小鼠溃疡性结肠炎模型的比较

Comparison of the models of ulcerative colitis induced by three kind of concentration of dextran sulfate sodium in mice

目的通过比较3种浓度葡聚糖硫酸钠(DSS)建立小鼠溃疡性结肠炎(UC)模型的成模情况及对相关促炎因子表达的影响,验证并筛选出成模率高、生存率高、经济的模型。方法将24只雄性C57BL/6J小鼠随机分为空白组、3%DSS组、4%DSS组、5%DSS组,每组6只。DSS各组小鼠自由饮用相应浓度DSS溶液(DSS溶液隔日更换1次),空白组小鼠自由饮水,连续6d。记录各组小鼠第1—6天体质量、便血情况和生存情况。造模6d后处死各组小鼠,观察结肠大体形态并测量结肠长度,取含病变肠组织制作病理切片行HE染色观察,采用RT-PCR法检测各组结肠组织中促炎因子白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)mRNA的表达情况。结果DSS各组小鼠前3d体质量保持平稳,第4天开始下降,且第2—6天体质量均明显低于空白组(P均<0.05);第6天时,4%DSS组小鼠体质量明显低于3%DSS组和5%DSS组(P均<0.05)。实验第1,2天各组小鼠未见肛门出血及肉眼血便,隐血试验阴性;实验第3天,3%DSS组1只小鼠出现肛门出血,4%DSS组3只小鼠出现肛门出血及肉眼血便,5%DSS组小鼠全部出现肛门出血及肉眼血便;4%DSS组和3%DSS组小鼠分别于实验第4天和第5天全部出现肛门出血及肉眼血便。实验第6天,空白组、3%DSS组、4%DSS组和5%DSS组存活率分别为100%,83.3%,83.3%,50%。DSS各组小鼠均出现UC病理表现,4%DSS组和5%DSS组尤为明显。DSS各组小鼠结肠组织中IL-1βmRNA表达量和4%DSS组、5%DSS组TNF-αmRNA表达量均明显高于空白组(P均<0.05),4%DSS组、5%DSS组IL-1β、TNF-αmRNA表达量均明显高于3%DSS组(P均<0.05),5%DSS组IL-1β、TNF-αmRNA表达量均明显高于4%DSS组(P均<0.05)。结论给予C57BL/6J小鼠4%浓度的DSS溶液饮用6d可高效经济地建立小鼠UC模型。

Objective It is to compare the success of establishing mice model of ulcerative colitis (UC) by three concentrations of dextran sulfate sodium (DSS) and influence on the expression of related proinflammatory factors, thus to verify and screen the economic models with high success rate and high survival rate. Methods Twenty-four male C57BL/6J mice were randomly divided into blank group, 3% DSS group, 4% DSS group and 5% DSS group, with 6 mice in each group. The mice in each group of DSS were free to drink the corresponding concentration of DSS solution (DSS solution was replaced once every other day), and the mice in the blank group were free to drink water, all the mice were treated for 6 days. The body mass, blood stool and survival of the mice in each group were recorded on the 1st to 6th day. After 6 days of modeling, the mice in each group were sacrificed. The gross morphology of the colon was observed and the length of the colon was measured. The pathological sections of the diseased intestinal tissues were taken for HE staining. The proinflammatory cytokines IL-1β and TNF-α mRNA in the colon tissues of each group were detected by RT-PCR. Results The mass of the first 3 days of DSS mice remained stable, and began to decrease on the 4th day, and the body mass of the 2nd-6th day was significantly lower than that of the blank group ( P <0.05). On the 6th day, the body mass of mice in 4% DSS group was significantly lower than that in the 3% DSS group and the 5% DSS group ( P <0.05). On the 1st and 2nd day of the experiment, no anal hemorrhage and gross bloody stool were observed in the mice of each group, the occult blood test was negative. On the third day of the experiment, there was 1 mouse with anal hemorrhage in the 3% DSS group, and 3 mice with anal hemorrhage and gross bloody stool in the 4% DSS group, all the mice had anal hemorrhage and bloody stools in the 5% DSS group. All the mice had anal hemorrhage and gross bloody stools on the 4th and 5th day of the experiment respectively in the 4% DSS group and the 3% DSS group. On the sixth day of the experiment, the survival rates of the blank group, 3% DSS group, 4% DSS group and 5% DSS group were 100%, 83.3%, 83.3%, and 50%, respectively. UC pathological changes were observed in all DSS mice, especially in the 4% DSS group and the 5% DSS group. The expression of IL-1β mRNA in colon tissue of DSS mice and the expression of TNF-α mRNA in 4% DSS group and 5% DSS group were significantly higher than those in blank group ( P <0.05). The expressions of IL-1β and TNF-α mRNA in the 4% DSS group, 5% DSS group were significantly higher than those in the 3% DSS group ( P <0.05). The expressions of IL-1β and TNF-α mRNA in the 5% DSS group were significantly higher than those in the 4% DSS group ( P <0.05). Conclusion The mouse UC model can be established efficiently and economically by giving 4% concentration of DSS solution in C57BL/6J mice for 6 days.