心肌缺血再灌注损伤肌浆网钙泵活性变化电镜酶细胞化学研究

Electron Microscopy and Enzyme Cytochemical Study on the Change of Sacoplasma Reticulum Ca^(2+)-ATPase in Ischemic and Reperfused Heart of Rats

目的 :研究心肌缺血再灌注损伤肌浆网、肌膜钙泵 (Ca2 + ATPase)功能变化。方法 :采用大鼠离体心脏模型应用电镜酶细胞化学及生化技术 ,研究缺血再灌注心肌肌浆网、细胞膜原位钙泵分布及活性变化。结果 :心肌细胞钙泵以高电子密度颗粒主要分布于肌浆网、肌膜等膜结构 ,缺血 30min钙泵反应产物显著减少 ,再灌注 30min及 6 0min酶进一步减少或缺失。生化钙泵活性测定显示心肌缺血 30min时为 (0 .0 48± 0 .0 10 ) μmol/mg·h-1,再灌注 6 0min为 (0 .0 6 9± 0 .0 18) μmol/mg·h-1,酶活性较对照组显著降低 (P <0 .0 1,P <0 .0 5 )。结论 :本研究揭示钙泵活性降低发生在心肌缺血期 ,钙泵功能抑制是心肌缺血再灌注损伤的重要环节 ,是亚细胞Ca2 +

Objective:This study was designed to examine the activity change of Ca 2+ ATPase of sarcoplasma reticulum and sarcolemmal in myocardial ischemic and reperfusion injury. Methods: The changes of the location, distribution, and activity of Ca 2+ ATPase in situ were determined by using electron microscopic enzyme cytochemical as well as a biochemical procedure. Results: The Ca 2+ ATPase was localized mainly within sarcoplasmic reticulum and sarcolemmal membrane structure. The activity of Ca 2+ ATPase was depressed significantly during ischemia, and the situation became worse at 30 and 60 minutes after reperfusion. A biochemical assay indicated that the activity of Ca 2+ ATPase was depressed 30 minutes after ischemia (0.048±0.010 μmol/mg·h -1 )and 60 minutes after reperfusion (0.069±0.018 μmol/mg·h -1 ,P<0.01, P<0.05, respectively). Conclusion: The inhibition of Ca 2+ ATPase activity occurred during ischemia, wich is the reason for Ca 2+ paradox in myocardial ischemia and reperfusion injury.