血红素氧合酶-1在大鼠急性烧伤后心肌中的变化

目的研究重度烧伤组和热预处理组大鼠心肌损害及心肌血红素氧合酶-1（HO-1）变化规律。方法将66只Wistar大鼠按随机数字表法分为3组：对照组、烧伤组和预处理组,每组22只。烧伤组造成30%体表面积Ⅲ度重度烧伤（ⅢTBSA）,预处理组大鼠先经肛温42℃热预处理30 min,室温24 h后再予烧伤,烧伤后1、3、6、12、24 h处死大鼠,检测心肌酶、心电图、心肌普通病理以及心肌组织内HO-1 mRNA和蛋白水平的变化等情况。结果对照组大鼠心电图正常,烧伤组烧伤后6、12 hⅡ导联心电图ST段抬高最明显;预处理组烧伤后12hⅡ导联心电图ST段抬高最明显。病理结果显示：烧伤组烧伤后6、12 h心肌细胞结构明显破坏;预处理组烧伤后12 h心肌细胞结构破坏。正常大鼠心肌组织HO-1 mRNA和蛋白水平均较低,与对照组比较,烧伤后HO-1水平明显升高,mR-NA在6、12 h达到高峰,6、12 h的mRNA水平分别是对照组（3.21±0.67）、（2.24±0.52）倍,差异有统计学意义（P〈0.05）,HO-1蛋白则在12 h左右达高峰,为对照组的（9.6±1.8）倍（P〈0.01）。预处理组HO-1 mRNA 6、12 h水平分别是对照组（5.68±0.76）、（3.54±0.55）倍,与对照组比较差异有统计学意义（P〈0.05）;HO-1蛋白水平12 h为对照组（13.3±2.5）倍,与对照组比较差异有统计学意义（P〈0.01）。结论重度烧伤可造成明显心肌损伤,热预处理可减轻心肌损伤,热预处理减轻重度烧伤后心肌损伤可能与HO-1有关。

The Effects of Heme Oxygenase-1 in Acute Post-burn Rat Myocardium

Objective To investigate the variation of myocardium injury and the level of heme oxygenase-1（HO-1）in severe burn rats in vivo.Methods Sixty-six Wistar rats were randomly divided into 3 groups with table of random number：control group,burn group,and heat pretreatment group.Rats were prepared with 30% of total body surface area Ⅲ degree burns in burn group.Rats were burned after pretreated with staying 42 ℃ for 30 min in heat pretreatment group.Changes of arrhythmia,ST segment in ECG,creatine kinase-MB isoenzyme（CK-MB） concentrate,and pathological section were analyzed at 1,3,6,12,and 24 h post-burn with rats sacrifice.And the level of HO-1 mRNA and protein was detected in myocardium,respectively.ResultsThe ECG was normal in control group.The elevation of ST-segment was obvious in lead Ⅱ during 6 h to 12 h post-burn in burn group.The elevation of ST-segment was obvious in lead Ⅱat 12 h post-burn in heat pretreatment group.The pathological analysis showed that the structure of cardiocyte destroyed obviously during 6 h to 12 h post-burn in burn group rats and 12 h post-burn in heat pretreatment group.The level of HO-1 mRNA and protein was low in control group rats,and raised rapidly after burn.Compared with the level in control group rats,the level of HO-1 mRNA was 3.21±0.67 and 2.24±0.52 at 6 h and 12 h in burn group,respectively（P〈0.05）.the level of HO-1 protein in burn was 9.6±1.8 times of that in control rats（P〈0.01）.In heat pretreatment group,the level of HO-1 mRNA was 5.68±0.76 and 3.54±0.55 times of that in control group at 6 h and 12 h,respectively（P〈0.05）.The expression of HO-1 protein increased 13.3±2.5 times of that in control group（P〈0.01）.Conclusion There was visible myocardial damage in the early of severe burn,especially at 12 h post-burn.Heat stress pretreatment ameliorated and delayed myocardium damage caused by severe burn,and provided a cardiac protection.HO-1 may be involved in the cardiac protection.