磁场作用下急性心肌梗塞大鼠心肌病理改变及相关自由基的变化

目的:探讨磁场对急性心肌梗塞（AMI）大鼠心肌的保护作用。方法：将大鼠随机分为空白对照组、磁场对照组、AMI组、AMI药物（心得安）治疗组和AMI磁场治疗组。采用黄嘌呤氧化酶法、硫代巴比妥酸（TBA）、虫荧光素酶法及放射免疫法检测实验性大鼠红细胞超氧化物歧化酶(SOD)、血浆丙二醛(MDA)、心肌三磷酸腺苷(ATP)含量及血浆环磷酸腺苷(cAMP)、环磷酸鸟苷(cGMP)及心肌梗塞范围(IS)，并对病理形态学、心电图进行观察。结果：AMI磁场治疗组红细胞SOD、心肌ATP明显高于AMI组（P<0.01），与药物治疗组比较差异无显著性（P>0.05）。AMI组血浆MDA、cAMP、cGMP含量明显高于空白对照组及磁场对照组（P<0.01），AMI磁场治疗组与药物治疗组明显低于AMI组（P<0.01）。光学显微镜观察结果表明，AMI组心肌梗塞处肉芽组织增生，未见明显瘢痕形成，磁场治疗组心肌梗塞处可见部分瘢痕形成。AMI磁场治疗组IS明显低于AMI组（P<0.05），AMI组ST段偏移和T波倒置出现率明显高于药物治疗组和磁场治疗组（ P<0.05）。结论:磁场能减少AMI大鼠IS、ST段偏移和T波倒置出现率，有利于梗塞处修复；能降低AMI大鼠血浆MDA、cAMP及cGMP的含量，增加红细胞SOD含量及心肌ATP含量，对心肌具有保护作用。

Changes of myocardium pathology and free radicals in experimental AMI rats treated with magnetic field

Objective To study the protective effect of magnetic field on acute myocardial infarction (AMI) rats. Methods The rats were randomly divided into 5 group: blank control group (Ⅰ),magnetic field control group (Ⅱ),AMI group (Ⅲ),AMI drug (propranolol) group (Ⅳ) and AMI magnetic field group(Ⅴ) . The SOD in RBC,plasma MDA,ATP content in myocardium,cAMP and cGMP in plasma and infarction scope(IS)were determined with xanthine oxidase,thiobarbituric acid,firefly luciferase and radioimmunological technique. Results The SOD in RBC and ATP myocardium in group Ⅴ were higher than that in group Ⅲ(P<0.01),but there was no signficant difference compared with group Ⅳ(P>0.05).The contents of plasma MDA,cAMP,cGHP in group Ⅲ were obvionsly higher than those in group Ⅰ and Ⅱ(P<0.01).Gruanulation tissue hyperplasia in myocardial infarction was found in group Ⅲ,but no obvious cicatrices.In group Ⅴ,some cicatrices were observed.The IS in group Ⅴ was lower than that in group Ⅲ (P<0.05),ST segment deflection and inverted T wave in group Ⅲ were higher than those in group Ⅳ and group Ⅴ(P<0.05).Conclusion Magnetic field can reduce the IS,ST segment deflection and inverted T wave,decrease the contents of plasma MDA,cAMP and cGMP,and increase the contents of SOD in RBC and ATP in myocardium in AMI rats.It has protective effect on myocardium.