心肌缺血再灌注损伤时细胞核钙含量与核孔复合体通透性的变化

Changes in nuclear calcium content and permeability of nuclear pore complex in rat myocardium during ischemia reperfusion injury

目的:探讨心肌缺血再灌注损伤时心肌细胞核钙含量与核孔复合体通透性的变化及其相互关系。方法:行大鼠心脏手术结扎左冠状动脉30 min后恢复灌注,分别于再灌注后15、30、60、120和180 min取出心脏,用蔗糖密度梯度离心法分离纯化心肌细胞核,用原子吸收分光光度法测定细胞核钙含量,用荧光标记的钙调素跨核膜转运法测定核孔复合体通透性。结果:心肌缺血30 min后再灌注153、0、60、120和180 min时,核钙含量分别较假手术组高1.31、1.55、1.73、1.94和2.14倍;而核孔复合体通透性在再灌注15 min时与假手术组比无明显差异,再灌注30、601、20和180 min时仅较假手术组高1.31、1.38、1.40和1.48倍。结论:心肌缺血再灌注损伤时,细胞核钙含量的增加早于核孔复合体通透性的增加,核孔复合体通透性的增加可能仅对核钙超载产生有限的代偿性调节作用。

AIM： To investigate the changes in nuclear calcium content and permeability of nuclear pore complex in rat rayocardium during ischemia reperfusion injury. METHODS： The rat model of myocardial ischemia reperfusion injury was established. Myocardial nuclei were purified using sucrose density gradient centrifugation. The nuclear calcium content was measured by atomic absorption spectrophotometer. The permeability of nuclear pore complex was assessed through measuring the amount of calmodulin conjugated Alexa FluoTM 488 as fluorescent probes transported across nuclear membrane with spectrofluorometer. RESULTS： The nuclear calcium content at 15, 30, 60, 120 and 180 min reperfusion foliowing 30 min sustained ischemia increased 1.31 - , 1.55 - , 1.73 - , 1.94- and 2.14- fold, respectively, as compared with shamoperation group. The permeability of nuclear pore complex at 15 min reperfusion following 30 min sustained iscbemia showed no difference from sham- operation group, but it only increased 1.31 - , 1.38 - , 1.40 - , and 1.48 - fold at 30, 60, 120 and 180 min repeffusion following 30 min sustained ischemia compared with sham- operation group. CONCLUSION： The ntwlear calcium content during myocardial ischemia reperfusion injury increases earlier than the permeability of nuclear pore complex does. The increase in the permeability of nuclear pore complex may result in adaptive regulatory effects on nuclear calcium overload to a certain extent during myocardial ischemia reperfusion injury.