氨甲喋呤诱导的大鼠持续性肠黏膜损伤模型的建立与评价

摘要: 目的：建立一种大鼠肠黏膜持续损伤模型。方法：SD大鼠腹腔注射氨甲喋呤（MTX）建立肠黏膜炎模型。100只大鼠随机分为空白组(Control Group)、模型组Ⅰ（MTX Group Ⅰ）、模型组Ⅱ (MTX Group Ⅱ)和模型组Ⅲ (MTX Group Ⅲ)，其中MTX Group Ⅰ10只大鼠，其余每组各30只。第0天，MTX Group Ⅰ大鼠注射MTX （20 mg/kg），MTX Group Ⅱ和 MTX Group Ⅲ大鼠注射MTX（10 mg/kg）。第6天，MTX Group Ⅱ大鼠再次注射MTX 10 mg/kg，MTX Group Ⅲ大鼠注射MTX 5 mg/kg。Control Group在第0天和第6天均注射生理盐水。实验期间观察大鼠活动状态，并记录进食量和体重变化。MTX Group Ⅰ在第4天全部处死，其余每组于造模后第4、5、6、10、11、12天各处死5只大鼠，HE染色进行病理学分析，并检测血浆中的D-乳酸、二胺氧化酶(DAO)及小肠组织中的髓过氧化物酶(MPO)、丙二醛(MDA)水平。结果：在第4天时，三个模型组大鼠小肠组织损伤评分(Chiu评分)均明显高于Control Group (p<0.05)，血浆中D-乳酸含量、DAO活力及小肠组织中MPO活力、MDA含量也均显著高于Control Group (p<0.05)。在第5天时MTX Group Ⅱ和 MTX Group Ⅲ大鼠小肠黏膜损伤程度开始恢复，Chiu评分、D-乳酸含量、DAO活力、MPO活力和MDA含量逐渐降低，在第6天时与Control Group基本无差异。二次注射后，在第10天，MTX Group Ⅱ和 MTX Group Ⅲ大鼠Chiu评分再次升高，血浆中D-乳酸含量、DAO活力及小肠组织中MPO活力、MDA含量也显著高于Control Group (p<0.05)，之后逐渐降低，损伤再次恢复。与MTX Group Ⅱ相比，二次注射后MTX Group Ⅲ损伤程度较轻（p<0.05）。结论：20 mg/kg MTX诱发大鼠肠黏膜炎是一个急性损伤过程，整个病程大约为4至5天，适用于药物治疗评价；两次间歇式10 mg/kg注射MTX可以造成大鼠肠黏膜的持续损伤，该模型更加适合中长期的营养治疗评价。

Establishment and assessment of a rat model of persistent intestinal mucosal injury induced by methotrexate

Objective To establish a rat model of persistent intestinal mucosal injury. Methods The rat model of persistent intestinal mucosal injury was induced by intraperitoneal injection of methotrexate. The food intake and body weight of all the rats were recorded. Pathological changes were observed using HE staining, the level of D-lactate and diamine oxidase in plasma, and myeloperoxidase and malondiadehyde in the intestinal tissue were measured by biochemistry. Results After modeling, the rat body weight and food intake were decreased. On day 4, the scores of mucosal damage, the levels of plasma D-lactate, DAO, MPO and MDA were significantly increased (P<0.05). On day 5, the intestinal damages of rats began to restore, and there was no significant difference among groups on day 6. The symptoms after the secondary injection were similar to those after the first injection, and the rats recovered gradually at day 12. Conclusions Intestinal mucosal injury in rats induced by 20 mg/kg MTX is an acute injury process, the course only lasts for 4-5 days. Intermittent injections twice of 10 mg/kg MTX can cause persistent intestinal mucosal injury in rats. This persistent injury model is more suitable for nutritional therapy evaluation in medium-and long-term studies of nutritional therapy.