吗啡预处理对离体心肌保护作用的研究

Protective effects of morphine preconditioning on myocardium in vitro

目的探讨吗啡预处理对离体心肌的保护作用。方法 20只家猪随机分为空白组和吗啡组,每组10只,建立猪不停跳心脏离体模型,在心脏离体前30 min,吗啡组给予静脉注射吗啡0.3 mg/kg预处理,空白组给予同等剂量生理盐水,分别于心脏离体即刻、保存2 h、4 h、6 h、8 h时取右心室肌小梁制备组织匀浆。采用羟安法检测心肌组织中超氧化物歧化酶(SOD)活性及丙二醇(MDA)、三磷酸腺苷(ATP)含量。结果两组动物均成功建立不停跳心脏离体模型。随着实验时间延长,空白组和吗啡组心肌MDA含量均上升,而心肌SOD活性、ATP含量下降(P<0.05);在各时间点,吗啡组SOD活性、ATP含量高于空白组(P<0.05),MDA含量低于空白组(P<0.05)。透射电镜下观察发现两组心肌细胞有不同程度的细胞水肿、线粒体肿胀,但空白组出现较明显的心肌细胞、线粒体结构破坏,吗啡组心肌细胞、线粒体结构比较完整。结论吗啡预处理对离体心肌有保护作用。

Objective To investigate the protective effects of morphine preconditioning on myocardium in vitro.Methods Twenty pigs were randomly divided into blank group（n=10） and morphine group（n=10）.A porcine beating-heart model in vitro was established.Thirty minutes before the porcine hearts were isolated,morphine group was given intravenous injection of morphine（0.3 mg/kg） for preconditioning,and blank group was given intravenously equal dose of normal saline.The ventricular trabeculae were taken out for tissue homogenate at the moment of heart isolation,2,4,6 and 8 hours after heart isolation,respectively.Chemical colorimetric assay was used to detect the activity of superoxide dismutase（SOD） of myocardium as well as the contents of malondialdehyde（MDA） and adenosine triphosphate（ATP） of myocardium.Results The porcine beating-heart model in vitro was established successfully in the two groups.In both of blank group and morphine group,the content of myocardial MDA increased,but the activity of myocardial SOD and the content of myocardial ATP decreased with the increasing experimental time（P〈0.05）.At all time points,morphine group showed higher activity of SOD,higher content of ATP and lower content of MDA compared with blank group（P〈0.05）.Cell edema and mitochondria swelling with different degrees were observed in myocardial cells under transmission electron microscope in the two groups.The structures of myocardial cells and mitochondria were damaged more obviously in the blank group,but the structures of myocardial cells and mitochondria were relatively complete in the morphine group.Conclusion Morphine preconditioning has protective effects on the myocardium in vitro.