大鼠心肌缺血再灌注时心肌细胞核1,4,5三磷酸肌醇受体结合特性改变的研究  

Change of cardiac myocyte nuclear inositol 1,4,5- trisphospate receptor binding proterties in rat with myocardium ischemic reperfusion

作　　者：张红[1] 周红[1] 司良毅[2] 张乐之[1] 何华美[1] 

机构地区：[1]第三军医大学第一附属医院老年科 [2]第三军医大学药理学教研室,重庆400038

出　　处：《中国药理学通报》2005年第7期822-826,共5页Chinese Pharmacological Bulletin

基　　金：国家自然科学基金资助项目(No30100070)

摘　　要：目的观察大鼠心肌缺血再灌注时心肌细胞核1,4,5三磷酸肌醇受体(IP3R)的结合特性改变,进一步探索心肌缺血再灌注时细胞凋亡的病理机制。方法TUNEL技术检测心肌细胞核凋亡率。蔗糖密度梯度离心法提纯心肌细胞核,放射配体分析法检测心肌细胞核膜上IP3R的结合特性变化。结果①缺血再灌注损伤(IRI)组大鼠心肌细胞凋亡率高于对照组(P<0.01)。②大鼠心肌缺血再灌注损伤时,心肌细胞核IP3R的最大结合容量Bmax较假手术组增加2.6倍;而其亲和力Kd值无明显变化。③IRI组心肌细胞核IP3R经激活的PKC磷酸化后结合特性增强1.54倍,对照组核IP3R经PKC磷酸化后结合特性无明显改变。④[Ca2+]对IRI组及假手术组心肌细胞核IP3R的调节均呈双相性,胞浆钙超载状态下([Ca2+]为5μmol·L-1时)较正常胞浆钙浓度下([Ca2+]为100nmol·L-1时),两组核IP3R结合特性均增强,[Ca2+]为100μmol·L-1时,两组核IP3R结合特性降低。结论大鼠心肌心肌缺血再灌注损伤病理情况下心肌细胞核IP3R结合特性增强,致核内钙浓度([Ca2+]n)增高,这可能是心肌缺血再灌注损伤中心肌细胞凋亡的主要病理机制之一。Aim Observing the alteration of cardiac myocyte nuclear inositol 1,4,5-trisphosphate receptor (IP_3R)binding proterties in rat subjected to myocardium ischemic reperfusion is to make it clear whether this change is involved in the molecule mechanism of cell apoptosis of rat with myocardial ischemic reperfusion. Method Apoptosis index of myocardial cell was determined using TUNEL assay.Extracting of cardiac myocyte nucleus was accomplished by saccharose density gradient centrifugation method,the binding proterties of nuclear IP_3R in different conditions were detected by radioligand binding assay.Results ①Myocardial cell apoptosis index in rat heart underwent 30 min regional ischemia and 3 h reperfusion was distinctly increased compared with sham-operated group(P<0.01). ②In IRI group, B_ max of nuclear IP_3R markedly increased by 2.6 folds compared to sham-operated group, whereas K_d value of nuclear IP_3R did not change.③In IRI group, the binding ability of phosphorylated nuclear IP_3R by activated protein kinase C increased by 1.54 folds, but its binding ability didn’t change in sham-operated group. ④In IRI and sham-operated groups, nuclear IP_3R were all biphasically regulated by cytosolic free [Ca 2+], with increased nuclear IP_3R binding ability at Ca 2+ concentration of 5μmol·L -1, which was the condition of cytosolic calcium overloaded,and their binding abilities declined at Ca 2+ concentration of 100 μmol·L -1. Conclusion The increasing of binding proterties of nuclear IP_3R from ischemic reperfusion heart may be one of important mechanism that is involved in myocardial cell apoptosis,further resulting in myocardium ischemic reperfusion injury.

关 键 词：缺血再灌注 细胞核 1 4 5三磷酸肌醇受体 细胞凋亡 

分 类 号：R-332[医药卫生] R322.11