不同浓度三硝基苯磺酸和乙醇诱导的大鼠克罗恩病模型

Crohn disease in rats induced by different concentrations of trinitrobenzenesulfonic acid and ethanol

目的:用三硝基苯磺酸(2,4,6-trinitrobenzenesulfonic acid,TNBS)和乙醇灌肠建立克罗恩病(Crohn disease,CD)大鼠模型,并比较不同乙醇浓度和用量对模型的影响。方法:按150 mg/kg标准,分别向大鼠肠道内灌注体积比为2:1的TNBS、50%乙醇混合液(实验1组),体积比为1:1的TNBS、50%乙醇混合液(实验2组),体积比为2:1的TNBS、无水乙醇混合液(实验3组),体积比为1:1的TNBS、无水乙醇混合液(实验4组)。生理盐水对照组注入等量生理盐水,正常对照组不予任何处理。于造模后第3、7、14和21天分批处死大鼠,观察各时间点结肠大体形态改变和组织学改变。结果:实验3组大鼠造模后1周内主要表现为肠壁非连续性糜烂、坏死及溃疡,镜下见大量炎性细胞浸润;第14天时黏膜呈鹅卵石样改变;第21天时病变明显好转,溃疡部位肠壁增厚明显,但光学显微镜下仍有明显炎症反应。实验1组在第3、7天时与实验3组的表现相似,第14天取材时症状和组织学改变均较实验3组轻,但组内大鼠间个体差异较大。实验2组第14天时大部分肠壁形态基本恢复正常。实验4组死亡率过高,组织损伤严重,且病理表现与克罗恩病差异较大。结论:体积比为2:1的TNBS、无水乙醇溶液灌肠造成的模型与人类克罗恩病症状表现近似,病理表现典型,炎症持续时间较长,是一种研究克罗恩病发病机制和评价治疗效果的较好的模型制备方法。

Objective： To induce Crohn disease in rats by intraluminal instillations of different concentrations of 2,4,6- trinitrobenzenesulfonic acid （TNBS） and ethanol. Metheds： Crohn disease in rats was induced with enema containing TNBS and 50% ethanol with volume ratio of 2 ： 1 （experimental group 1） or 1 ： 1 （experimental group 2）, or solution containing TNBS and anhydrous ethanol with volume ratio of 2 ： 1 （experimental group 3） or 1 ： 1 （experimental group 4：）. Equivalent volume of normal saline was used to set as the normal saline control, and rats without any treatment were set as the normal control group. The rats were killed at various time points （3, 7, 14 and 21 d） respectively. Colonic inflammation and damage were assessed macroscopically and histologically. Results： In the colon of rats in the experimental group 3, discontinuous erosion, ulceration and infiltration of neutrophils occurred after one week; pebble sign and even segmental inflammation appeared on day 14：. On day 21, it appeared improvement in the colon tissue and obviously thickened bowel wall, but the inflammation was easily observed under the light microscope. Experimental group 1 was similar to experimental group 3 in appearance of the colon on days 3 and 7; on day 14, colonic inflammation and damage were improved as compared with the experimental group 3, but there were obvious individual differences in histological findings among rats in group 1. In the experimental group 2, the intestinal wall turned to be normal on day 14. In the experimental group 4, there were high mortality and extensive damage of colon tissues, and the pathological characteristics were quite different from Crohn disease in humans. Conclusion： The characteristics of the rat model of Crohn disease induced with a enema containing TNBS and anhydrous ethanol with volume ratio of 2 ： 1 are similar to the clinical features of human Crohn disease, including typical pathological characteristics and long duration of inflammation. It may be an ideal experimental model for studying pathogenesis of Crohn disease and for evaluating treatment effects.