应激大鼠胃黏膜氧化应激指标受褪黑素影响的研究

Effects of melatonin on oxidative stress parameters in rats with stress ulcer

目的探讨褪黑素干预应激大鼠胃黏膜氧化应激指标影响的研究。方法采用浸水-束缚(WIR)应激实验复制大鼠应激性溃疡模型。应激前30 min,MT(melatonin)5、20mg.kg-1和应激组大鼠分别腹腔注射MT 52、0mg.kg-1和等体积生理盐水。应激6h后,观察各组大鼠胃黏膜病变情况,对溃疡指数(UI)进行评分,同时检测各组大鼠胃黏膜内丙二醛(MDA)含量、胃黏膜超氧化物歧化酶(SOD)活性和还原型谷胱甘肽(GSH)水平。结果WIR应激6h后,应激组大鼠胃黏膜MDA水平显著高于对照组(P<0.01)。MT 52、0mg.kg-1组较应激组MDA水平显著下降(P<0.01),且MT 20mg.kg-1组显著低于MT 5mg.kg-1组(P<0.01)。应激组大鼠SOD、GSH活性较对照组明显降低(P<0.01),MT 5、20mg.kg-1组较应激组SOD、GSH活性有升高趋势。比较各组UI发现,MT 5、20mg.kg-1组UI显著低于应激组(P<0.01),其中MT 20mg.kg-1组UI显著低于MT 5mg.kg-1组(P<0.05)。结论褪黑素通过其抗氧化的作用对应激大鼠胃黏膜损伤起保护作用。

Objective To investigate the effects of melatonin on（MT） Oxidative stress parameters in rats with stress ulcer. Methods Stress ulcer was induced by water-immersion rest raint （WIR） stress for 6h. Results MT（5 and 20 mg/ kg, ip） was administrated 30min prior to WIR stress. After 6h of WIR, rats were killed and the stomachs were removed. Ulcer index （UI） was evaluated macroscopically and gastric mucosal MDA, SOD, GSH levels were determined. After 6h of WIR, mucosal MDA level got evidently higher than that in the normal control （ P 〈 0.01 ）, but administration of melatonin （5 and 20 mg/kg, ip） 50 min prior to stress can significantly inhibit the increase of mucosal MDA content （ P 〈 0.01 ）, which in the group of MT 20 mg·kg^-1 got lower than that in the group of MT 5 mg·kg^-1. Compared with the normal group, SOD and GSH levels can be reduced by WIR （P 〈 0.01）, but protection of melatonin （5 and 20 rog/kg, ip） 50 min prior to stress can increase both SOD and GSH. UI in protection group of melatonin （5 or 20 mg/kg, ip）was lower than that in WIR group（ P 〈 0.01） ,and which in MT 20 mg· kg^- 1 group was even lower than that in MT 5 mg·kg^-1 group （ P 〈 0.05）. Conclusion Melatnonin can prevent the development of stress ulcer via a mechanism involving in reducing oxidative stress.