地塞米松抗氧化作用及其对I/R大鼠心脏功能和超微结构的影响

The antioxidative action of dexamethasone and effect on cardiac function and myocardial ultrastructure during I/R in rats

目的探讨地塞米松的抗氧化作用及其对缺血-再灌注(I/R)大鼠心脏功能和心肌超微结构的影响。方法SD大鼠随机分成地塞米松组、对照组,分别予地塞米松和生理盐水预处理。24小时后构建Langendorff离体心脏I/R动物模型,缺血30min后再灌注60min,动态观测缺血前及再灌注期间心脏功能的改变;测定心肌丙二醛(MDA)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化酶(GSH-Px)水平;观察心肌超微结构变化。结果与对照组相比,地塞米松组MDA水平显著降低(P<0.01),SOD、CAT、GSH-Px水平显著升高(P<0.05);地塞米松可改善再灌注期间心脏功能(LVDP、±dp/dtmax、CFP<0.01)及减轻缺血再灌注后心肌超微结构的损伤。结论地塞米松升高I/R心肌组织抗氧自由基酶的水平,抑制脂质过氧化反应,对缺血再灌注大鼠的心脏具有延迟保护作用。

Objective To explore the antioxidative action of dexarnethasone （DEX） on cardiac function and myocardial ultrastructure during I/R in rats. Methods 48 Sprague-Dawley rats were divided randomly into the DE）（ and control （CON） group, the rats had been pretreaded with DEX or sodium chloride for 24 hours before their hearts were separated for Langendorff pedusion and I/R. The left ventricular function （LVDP,＋dp/dtmax） and coronary artery flow （CF） were observed dynamically before ischemia and during 60-minute reperfusion following 30-minute ischemia, and the myocardial ultrastructures were also examined. The myocardial malonaldehyole （MDA）, superoxide dismutase （SOD）, catalase （CAT）, glutathione peroxidase （GSH-Px） were detected at repedusion 60 minutes. Results Compared with CON group, the MDA was significantly lower （P〈0. 01） and the SOD, CAT, GSH-Px were significantly higher in DE）（ group （P〈0. 05）, the LVDP, ＋dp/dtmax, -dp/dtmax and CF were greatly improved （P（0. 01）, the I/R injury of myocardial ultrastructure was decreased. Conclusion Dexamethasone can enhance the myocardial activity of antioxidase and inhibit lipid peroxidation, which functions to protect myocardium against I/R injury in rat heart.