实验性结肠炎中氧化过度及褪黑素的保护作用

目的　探讨褪黑素对大鼠免疫性结肠炎的影响及有关机制。方法　应用三硝基苯磺酸和乙醇制备大鼠免疫性结肠炎模型。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 ,1 0 0mg·kg- 1 )、褪黑素给药组 (2 5 ,5 0 ,1 0 0mg·kg- 1 ) ,每天灌肠给药 1次 ,给药时间从制备模型 1wk后开始至实验结束共 3wk。观察大鼠结肠黏膜损伤指数 (CMDI)、粪便隐血实验 (OB)、髓过氧化物酶 (MPO)含量和黏膜病理组织学 (HS)情况 ,并检测结肠组织丙二醛(MDA)、谷胱甘肽过氧化物酶 (GSHPx)、过氧化氢酶(CAT)、超氧化物歧化酶 (SOD)、血浆和结肠组织一氧化氮(NO)含量。结果　模型组大鼠结肠CMDI、HS、OB程度和MPO水平均比正常组升高 ,褪黑素可改善结肠炎大鼠CM DI和HS ,降低MPO水平和粪便OB程度 ,改善结肠黏膜病理损伤 ,大鼠结肠MDA、血浆和结肠NO含量增加 ,结肠SOD、GSHPx和CAT水平降低 ,MT可降低MDA、NO含量 ,增加GSHPx、SOD和CAT水平。结论　MT对大鼠结肠黏膜损伤具有保护作用

Oxidative stress in rats colitis and the action of antioxidant

AIM To investigate the effects of melatonin on rats colitis induced by 2,4,6 trinitrobenzene sulfonic acid(TNBS) with ethanol and its mechanism. METHODS The rats colitis model was produced by TNBS and ethanol enemas.The experiment 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 intracolonically with normal saline, 5 ASA and MT respectively (1 time per day, from d 7 after the establishment of colitis model to the end of the experiment). At the end of the experiment, the colon 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, and the content of malondiadehyde (MDA), glutathione peroxidase (GSHPx), catalase (CAT), superoxide dismutase (SOD) in rats colon, nitric oxide (NO) in rats plasma and colon were detected. RESULT MT(2 5, 5 0, 10 0 mg·kg -1 ) can ameliorate the exetent of CMDI and OB, reduce the level of MPO and alleviate the HS of rats which were all elevated in model group. MT intracolonicly can depress the content of MDA, NO in colon which elevated in model group, promote the content of GSHPx, SOD and CAT in colon which decreased in model group. CONCLUSION MT has beneficial effects on the rats colon damage induced by TNBS and ethanol.