摘要
目的观察褪黑素在大鼠肠缺血—再灌注损伤中对肠黏膜屏障的影响并探讨其作用机制。方法将成年雄性SD大鼠60只分为假手术组10只、缺血-再灌注组10只、缺血—再灌注+溶媒组10只、缺血—再灌注+褪黑素(10 mg/kg)组15只、缺血—再灌注+褪黑素(20 mg/kg)组15只。观察肠缺血30 min再灌注60 min后肠黏膜损伤程度,测定小肠组织中丙二醛(MDA)及血中D-乳酸和内毒素水平,并测定小肠组织中超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活力。结果运用褪黑素明显降低了缺血—再灌注后组织中MDA水平的增加,同时褪黑素组与缺血—再灌注组比较SOD、CAT的活力升高。组织学显示褪黑素组肠黏膜损伤程度轻于缺血—再灌注组,血浆中D-乳酸和内毒素含量均低于缺血—再灌注组和溶媒组。褪黑素治疗产生的这种变化呈剂量依赖效应。结论褪黑素通过有效清除自由基和提高抗氧化酶活力明显减轻了大鼠肠缺血—再灌注后对肠黏膜屏障功能的损害。
Objectives Melatonin, a pineal hormone, is a free radical scavenger and an antioxidant. The aim of this study was to investigate the effect of melatonin on the prevention of intestinal barrier injury induced by intestinal ischemia-reperfusion （IIR） in rats. Methods IIR injury was induced in rats by champing the superior mesenteric artery for 30 min, followed by the release of the clamp （reperfusion）. Melatonin （10, 20 mg/kg） or vehicle （control, 2% alcohol） was administered twice, 5 min prior to and 30 min after reperfusion. At 60 min after reperfusion, rats were decapitated. Ileum samples were taken for histological examination or the determination of tissue malondialdehyde （MDA）, catalase （CAT） and superoxide dismutases （SOD） activities. Plasma D （-）-lactate and endotoxin concentrations were measured for the evaluation of intestinal permeability. Results As compared to the sham-operation group, D（-）-lactate, endotoxin and MDA were significantly increased, while SOD and CAT were deceased in ischemia-reperfusion group. As compared to ischemia-reperfusion group and vehicle administered group, these changes were reversed to some degrees in a dose-dependent manner with melatonin treatment. The histopathological results were consistent with the biochemical markers. Conclusions In this study, exogenously administered melatonin effectively protected intestinal barrier function from ischemia-reperfusion injury, and this may be due to its clearance of free radicals and improvement of anti-oxidase activities.
出处
《兰州大学学报（医学版）》
CAS
2006年第3期31-34,39,共5页
Journal of Lanzhou University（Medical Sciences）
关键词
褪黑素
缺血-再灌注
肠屏障功能
自由基
melatonin
ischemia-reperfusion
intestinal barrier function
free radicals
