乙酸诱导建立大鼠急性直肠黏膜损伤模型的形态学观察

摘要]目的：通过形态学观察评价乙酸诱导建立急性直肠黏膜损伤模型的效果。方法：将含有4%乙酸溶液的棉签经SD大鼠肛门置入直肠1min，置入深度为3cm，诱导大鼠形成急性直肠黏膜损伤，并于损伤后0.5h、1d、4d、6d分别解剖大鼠，对直肠进行大体形态观察和组织病理学分析。结果：损伤后大鼠6d内全部存活，模型成功率为100％。损伤后0.5h~1d，大鼠直肠黏膜大体形态由充血、水肿和溃疡到合并出血，镜下形态见黏膜层由上皮组织坏死伴出血到黏膜组织全层坏死，腺体由部分留存到全无，黏膜下层由水肿到合并充血、出血，间质内由血管扩张充血到炎细胞浸润；损伤后4d~6d，直肠黏膜大体形态仍可见部分水肿和血丝，镜下形态见黏膜上皮有部分留存，损伤部位有炎性肉芽组织增生，黏膜充血、出血减轻。结论：4%乙酸作用于直肠1min能成功诱导建立大鼠急性直肠黏膜损伤模型，该模型操作方便、成功率高、重复性好，损伤维持时间6d以上，适合作为快速筛选直肠外用药物疗效的动物模型。

Morphological characterization of the rat model of acetic acid-induced acute rectal mucosal injury

Objective To establish a reproducible rat model of acute rectal mucosal injury induced by acetic acid. Methods Fifteen healthy Sprague-Dawley rats were randomly divided into the control group (3 rats) and experimental group (12 rats). Acute rectal mucosal injury was induced by 4% acetic acid using a cotton swab inserted into the rat rectum for 1 min to a depth of 3 cm. The morphological characteristics were analyzed by the naked eye and histology at 0.5 h and 1, 4, and 6 days after acetic acid intervention. Results All rats survived 6-day study period. The successful rate of model establishment was 100%. From 0.5 h to 1st day after acetic acid intervention, the gross morphology of recta showed congestion, edema and ulcer to ulcer complicated with hemorrhage. The histology showed necrosis and hemorrhage of the epithelial tissue of the mucosa to complete and extensive necrosis of the mucosa. The glandular structure showed partial to complete loss. The submucosa showed edema to edema complicated with hemorrhage and congestion. The interstitial tissues showed vasodilatation and congestion to inflammatory cell invasion.From 4 to 6 days after acetic acid intervention, the rectal mucosal changes were obviously improved. Epithelial and glandular regeneration and inflammatory granulation occurred, but not fully recovered, some edema and redness, partial lack of glands were still present. Conclusions 4% acetic acid for 1 min can be used to successfully induce rat model of acute rectal mucosal injury. This procedure is easy to operate, with a high success rate, reproducible, and the alterations are lasting more than 6 days. This animal model is very suitable for rapid screening of topical drugs for the treatment for rectal mucosal injury.