家兔未成熟心肌缺血再灌注肌浆网摄钙功能的初步研究

PRIMARY STUDY OF SR Ca^( 2+) -ATPase ACTIVITY OF IMMATURE MYOCARDIUM RABBITS OF IN ISCHEMIA-REPERFUSION

目的 :从亚细胞水平研究未成熟心肌缺血 -再灌注损伤中肌浆网 (SarcoplasmicReticulum ,SR)摄钙功能。方法 :36只家兔随机分为 4组 ,进行离体心灌注。组Ⅰ :幼兔 ,单纯灌注 30min ;组Ⅱ :幼兔 ,停搏 6 0min ,再灌注 30min。组Ⅲ、组Ⅳ为成兔 ,处理分别同组Ⅰ、组Ⅱ ,进行对照。测定各组心功能、冠状动脉流出液血气 ,单细胞内游离钙离子浓度 ([Ca2 + ]i) ,肌浆网Ca2 + -ATPase活性 ,肌浆网45Ca2 + 摄取。结果 :缺血 -再灌注后 ,成熟与未成熟心肌均发生钙超载 (P >0 .0 5 )。未成熟心肌肌浆网Ca2 + ATPase活性 ,肌浆网45Ca2 + 摄取恢复率 ,明显高于成熟心肌 (P <0 .0 5 )。结论 :未成熟心肌缺血 -再灌注损伤钙超载机制不同于成熟心肌 ,肌浆网钙摄取功能 ,在钙超载损伤中不起主要作用。

Objective:To determine the SR Ca 2+ -ATPase activity of immature myocardium during ischemia/reperfusion.Methods:Thirty-six isolated rabbit hearts were divided into four groups. GroupⅠ : Immature rabbits, perfused for 30 minitues. Group Ⅱ :Immature rabbits, whose hearts underwent cardioplegic arrest for 60 minitues, followed by 30 minitues of reperfusion. Group Ⅲ and group IV were mature rabbits, whose hearts underwent the same treatment. The cardiac function, the blood gas of the coronary flow, the density of intracellular free calcium, sarcoplamic reticulum(SR) Ca 2+ -ATPase activity , 45 Ca 2+ uptake were evaluated. Results:The SR Ca 2+ -ATPase activity, the 45 Ca 2+ uptake of mature myocardium were markedly decreased during ischemia/reperfusion, but that of immature myocardium did not obviously change.Conclusions:The recovering rate of SR Ca 2+ -ATPase activity and 45 Ca 2+ uptake in immature rabbit hearts is significantly higher than that in the mature rabbit hearts. The SR Ca 2+ uptake function of immature heart does not play a dominant role in Ca 2+ overload during ischemia/reperfusion.