MT对大鼠乙酸性结肠炎的影响及有关机制初探

The effects of melatonin on rats colitis induced by cetic acid and its mechanism

目的 探讨褪黑素对大鼠乙酸性结肠炎的影响及有关机制。方法 制备大鼠乙酸性结肠炎模型 ,实验设正常对照组、模型对照组、阳性药物对照组 (5 氨基水杨酸 ,10 0mg·kg-1)、MT给药组 (2 5 ,5 0 ,10 0mg·kg-1) ,采用灌肠方式给药 ,每天 1次 ,给药时间从制备模型 2 4h后开始至实验结束共 7d ,正常及模型对照组均给予生理盐水灌肠。实验结束后观察大鼠结肠粘膜损伤指数 (CMDI)、粪便隐血实验(OB)、髓过氧化物酶 (MPO)含量和粘膜病理组织学 (HS)情况 ,并检测结肠组织丙二醛 (MDA)、谷胱甘肽过氧化物酶(GSH Px)、过氧化氢酶 (CAT)、超氧化物歧化酶 (SOD)、一氧化氮 (NO)含量。结果 乙酸性结肠炎大鼠结肠CMDI、HS、OB程度和MPO水平均比正常组明显升高 ,MT灌肠可减轻乙酸性结肠炎大鼠的CMDI和粪便OB程度 ,降低MPO水平 ,10 0mg·kg-1MT可改善结肠粘膜病理损伤。同时可见模型组大鼠结肠组织MDA、NO含量增加 ,SOD、GSH Px和CAT水平降低。MT可明显降低MDA、NO含量 ,增加GSH Px、SOD和CAT水平。

AIM To investigate the effects of melatonin on rats colitis induced by acetic acid and its mechanism. METHODS The rats colitis model was produced by acetic acid enemas. The experimental animals was divided into 6 groups: normal group,model group,5 ASA group(100 mg·kg -1 ),MT group(2 5,5 0,10 0 mg·kg -1 ), and treated intracolonic with saline,5 ASA and MT correspondingly (1 time per day, from the 24 h after the establishment of colitis model to the end of the experiment). At the end of the experiment, the mucosal damage index(CMDI),the level of myeloperoxidase(MPO), the score of histology(HS) in rats colon and the occult blood test(OB) in feces were observed and measured, meanwhile, the content of malondiadehyde(MDA), glutathione peroxidase(GSH Px),catalase (CAT), superoxide dismutase(SOD), nitric oxide(NO) in rats colon were detected. RESULTS After being treated with acetic acid, the exetent of OB, CMDI, HS and the level of MPO in model group were more higher than that in normal group, MT(2 5,5 0,10 0 mg·kg -1 ) ameliorated the exetent of CMDI and OB and reduced the level of MPO, MT(10 0 mg·kg -1 ) alleviated the HS of rats in model group. Meanwhile in model group, the content of MDA,NO in colon elevated, but the content of GSH Px,SOD and CAT in colon reduced remarkably. MT intracolon depressed the content of MDA,NO in colon, promote the contents of GSH Px?SOD and CAT in colon. CONCLUSION Treatment with MT shows beneficial effects on the mucosal damage of rats colitis induced by acetic acid.