纳洛酮对兔心肌缺血-再灌注损伤β-内啡肽的影响

目的: 探讨纳洛酮在心肌缺血-再灌损伤时对血浆及心肌匀浆β-内啡肽(β-EP) 的影响。方法: 新西兰兔45 只, 随机分成5 组:正常组5 只, 心肌缺血组、缺血再灌注组、纳洛酮保护组和纳洛酮治疗组,每组10 只。制作心肌缺血模型和缺血再灌注损伤模型, 并抽取不同时间点的静脉血, 在心肌缺血、缺血再灌注、纳洛酮保护和纳洛酮治疗后6 h 制作缺血心肌匀浆, 采用放射免疫法分别测定β-EP 的含量。结果: 心肌缺血2 h 后血浆β-EP 含量逐渐下降, 较缺血前显著降低(P<0.05) ;而心肌匀浆上清液β-EP 含量也降低。缺血再灌注后各时段β-EP 含量明显高于缺血前(P<0.05或P<0.01) ;纳洛酮保护组在4 h 后血浆β-EP 含量逐渐下降, 与缺血前比较无显著性差异(P >0.05) ;纳洛酮治疗组β-EP在缺血后各时间点与缺血前比较均无显著性差异(P >0.05) 。3 组心肌匀浆上清液β-EP 含量与缺血前的含量比较无明显变化。结论: 纳洛酮可有效降低心肌缺血及缺血再灌注损伤时血浆β-EP 水平;从而减轻β-EP 对血管和心肌组织的损伤作用。

Effects of naloxone on β-endorphin during myocardial ischemia-reperfusion injury in rabbits

AIM: To study the effects of naloxone on β-endorphin (β-EP) in plasma and myocardium homogenate during myocardial ischemia-reperfusion (I R) injury in rabbits.METHODS: 45 New Zealand rabbits were randomly assigned into 5 groups (5 rabbits in control group, and each 10 rabbits in ischemia group, naloxone protection group, naloxone treatment group and ischemiareperfusion group).Myocardial ischemia models andmyo- cardial ischemia-reperfusion injury models in rabbits were made by means of ligating the left anterior descending branch of coronary artery and then investigated the change of β-EP in plasma and myocardium homogenate during I R injury after the protection and treatment with naloxone (an antagonist of opiate receptor).The blood and myocardium homogenate were taken at different times in each group.The levels of β-EP were detected with radioimmunology method.RESULTS: The levels of β-EP in plasma began to decrease after 2 h of ischemia, which were strikingly different to those before ischemia(P<0.05), and the levels of β-EP in myocardium homogenate also decreased.Comparing with those before ischemia, the levels of β-EP increased significantly after I R injury (P<0.05 or P<0.01), whereas its levels began to decrease after 4 h of I R and had no significant difference in naloxone protection group(P >0.05), but the treatment group showed no significant change(P >0.05).The levels of β-EP in myocardium homogenate had no difference to those before ischemia in all of three groups.CONCLUSION: Naloxone may effectively reduce the levels of β-EP during myocardial ischemia and I R injury, which decrease the injury to blood vessel and myocardium.