New In Vivo Apoptosis Model of Cardiomyocytes and Bcl-2 gene therapy

目前还没有合适的凋亡心肌细胞的体内模型。本研究的目的是建立一种新的心脏凋亡模型，并采用可溶性Fas配体（sFL）直接注射到成年大鼠心脏和肝脏的方法，比较在体成年大鼠心脏和心脏的心肌细胞和间质细胞对凋亡信号的敏感性、凋亡清除率和超微结构。为使全身性影响最小化，将可溶性Fas配体以0、0.5、2和5 μg/mL（C、F0.5、F2和F5组）直接注射到大鼠体内心脏和肝脏（作为对照）。心脏的凋亡心肌细胞和凋亡非心肌细胞仅在F5中被鉴定为具有相似的发生率。注射后12小时达高峰（2.0±0.09%）， ...更多信息 24小时后明显消失。Caspase-3仅在F5中被激活。泛胱天蛋白酶抑制剂Boc-Asp-fetoxin可抑制细胞凋亡，表明凋亡敏感性受caspase-3上游调控。凋亡的非心肌细胞具有典型的超微结构。除了典型的超微结构，如细胞皱缩，染色质凝聚，凋亡小体，然而，凋亡心肌细胞表现出独特的功能：甜甜圈样，而不是半月形或新月形，染色质凝聚：频繁的质膜破裂，即使在早期阶段;凝聚的线粒体内有皱纹嵴;细胞质脂质样液滴的外观;和肌原纤维紊乱。在肝脏中，即使在F0.5组中，在肝细胞和非肝细胞中也诱导了典型的细胞凋亡，24小时后这些细胞被清除。与肝细胞相比，心脏的心肌细胞和非心肌细胞对凋亡信号的抵抗力更强，但清除同样迅速（24小时内）。凋亡心肌细胞的超微结构是独特的。这些发现为心脏细胞死亡的动力学提供了新的见解。少

There is no adequate in vivo model of apoptotic cardiomyocyte. The purpose of the present study was to develop a new apoptosis model of heart, and to delineate sensitivity to the apoptotic signal and the clearance rate and ultrastructure of apoptosis in in vivo adult cardiomyocytes and interstitial cells of the heart in comparison with those of hepatocytes and interstitial cells of the liver by use of a direct injection method of soluble Fas ligand (sFL) into adult rat hearts and livers. In addition, it was studied whether Bcl-2 gene therapy can inhibit the Fas-induced apoptosis.To minimize the systemic influence, soluble Fas ligand was injected directly into in vivo rat hearts and livers (as the control) at concentrations of 0, 0.5, 2, and 5 μg/mL (groups C, F0.5, F2, and F5). Apoptotic cardiomyocytes and apoptotic noncardiomyocytes of the heart were identified with similar incidences only in F5. Their incidents peaked at 12 hours after injecction (2.0±0.09% in cardiomyocytes) and dim … More inished markedly 24 hours later. Caspase-3 was activated only in F5. Boc-Asp-fmk, a pancaspase inhibitor, inhibited apoptosis, suggesting that the apoptosis sensitivity was regulated upstream of caspase-3. Apoptotic noncardiomyocytes showed typical ultrastructure. In addition to the typical ultrastructure, such as cellular shrinkage, chromatin condensation, and apoptotic bodies, however, apoptotic cardiomyocytes showed unique features : doughnut-like, but not half-moon- or crescent-like, chromatin condensation : frequent plasma membrane rupture even during the early stage ; condensed mitochondria with wrinkled cristae inside ; the appearance of cytoplasmic lipid-like droplets ; and myofibrillar derangement. In the livers, typical apoptosis was induced in hepatocytes and nonhepatocytes of the liver even in the F0.5 group, which were cleared 24 hours later. Bcl-2 gene therapy blocked significantly apoptotic cells.Compared with liver cells, cardiomyocytes as well as noncardiomyocytes of the heart are more resistant against the apoptotic signal, but the clearance is similarly rapid (within 24 hours). The ultrastructure of apoptotic cardiomyocytes is unique. These findings provide new insights into the dynamics of cell death in the heart. Less