血红素氧合酶-1在大鼠烧伤后心肌再灌注损伤中的表达及意义

Effects of Heme Oxygenase-1 in Myocardial Reperfusion Injury in Post-burn Rats

目的研究血红素氧合酶(HO-1)对烧伤后大鼠心肌缺血再灌注损伤中的表达。方法 32只大鼠按随机数字表法分为烧伤组、热预处理组、热预处理+ZnPP组、热预处理+ZnPP+Hemin组,每组8只。所有大鼠心脏进行离体Langendorff恒压灌流,分别记录大鼠心电图、左室压(LVDP)、左室内压变化速率(±dp/dtmax),检测CK、心肌梗死面积及心肌组织HO-1mRNA和蛋白水平。结果大鼠烧伤后心脏缺血-再灌注可造成明显损伤,热预处理可明显减轻心脏的缺血-再灌注损伤、缩小心肌梗死面积、改善心肌收缩力;ZnPP可降低HO-1水平,抑制预处理对心脏的保护作用;Hemin通过增加HO-1水平,取消ZnPP对预处理心脏保护的抑制作用、改善心肌收缩、减少梗死面积。结论烧伤后再灌注可对心脏产生损伤,热预处理可减轻心脏再灌注损伤,HO-1可能参与其保护作用。

Objective To evaluate the role of heme oxygenase-1（HO-1）on myocardial reperfusion injury in post-burn rats.Methods Thirty-two rats were randomized into 4 groups：burn group,heat pretreatment group,heat pretreatment＋ZnPP group,and heat pretreatment＋ZnPP＋Hemin group,with 8 rats in each group.Hearts were isolated and perfused according to the Langendorff technique at constant pressure.ECG,LVDP,±dp/dtmax,heart rate,and CK were measured with a multichannel physiologic recorder.Myocardial infarct size and the levels of HO-1 mRNA and protein were detected.Results Myocardial injury was induced by ischemia-reperfusion procedure in post-burn rats.Heat pretreatment significantly alleviated the injury,decreased the size of infarction,and ameliorated myocardial contractility.ZnPP inhibited the cardiac protection of pretreatment and attenuated myocardial contractility through the inhibition of HO-1.Hemin blocked the inhibition of ZnPP,ameliorated myocardial contractility,and restored pretreatment effects on ischemia-reperfusion injury through increasing the levels of HO-1.Conclusion Reperfusion is harmful to myocardium in post-burn rats,and heat pretreatment may alleviate the injury involving the expression of HO-1.