Structural remodelling of cardiomyocytes in the border zone of infarcted rabbit heart
Structural remodelling of cardiomyocytes in the border zone of infarcted rabbit heart
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DOI：
10.1007/s11010-007-9445-2
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发表时间：
2007-08-01
影响因子：
4.3
通讯作者：
Borgers, Marcel
中科院分区：
文献类型：
--
作者：
Driesen, Ronald B.;Verheyen, Fons K.;Borgers, Marcel
心肌细胞去分化，如在慢性缺血患者的冬眠心肌中检测到的，是在小型和大型动物心肌梗死边缘观察到的特征之一。本实验旨在详细研究家兔心肌梗死边缘区的形态学变化及其作为冬眠心肌模型的应用。结扎兔左冠状动脉（LAD），分别于梗死后2、4、8和12周处死动物。将这些心脏与非梗塞对照心脏一起灌注固定，并将组织样品包埋在环氧树脂中。冬眠心肌细胞主要分布在梗死心肌边缘区的非梗死区，但数量有限。在边界区本身，经常观察到被纤维化组织包围的空泡化心肌细胞。这些空泡化细胞的超微结构分析显示，存在一个基膜内的空泡邻近周围的膜，胞饮小泡的存在和与肌浆网池的协会。心肌细胞定量分析显示，空泡面积/总细胞面积比和胶原纤维沉积内的空泡从梗死后2至12周逐渐增加。与远区相关，位于边缘区和邻近边缘区的肌细胞的细胞宽度增加表明细胞肥大。这些结果表明在梗死心肌的边缘区和邻近区域中发生了心肌细胞重构机制。有人建议，空泡代表质膜内陷和/或T-管状结构的膨胀。
Cardiomyocyte dedifferentiation, as detected in hibernating myocardium of chronic ischemic patients, is one of the characteristics seen at the border of myocardial infarcts in small and large animals. Our objectives were to study in detail the morphological changes occurring at the border zone of a rabbit myocardial infarction and its use as model for hibernating myocardium. Ligation of the left coronary artery (LAD) was performed on rabbit hearts and animals were sacrificed at 2, 4, 8 and 12 weeks post-infarction. These hearts together with a non-infarcted control heart were perfusion-fixed and tissue samples were embedded in epoxy resin. Hibernating cardiomyocytes were mainly distributed in the non-infarcted region adjacent to the border zone of infarcted myocardium but only in a limited number. In the border zone itself vacuolated cardiomyocytes surrounded by fibrotic tissue were frequently observed. Ultrastructural analysis of these vacuolated cells revealed the presence of a basal lamina inside the vacuoles adjacent to the surrounding membrane, the presence of pinocytotic vesicles and an association with cisternae of the sarcoplasmatic reticulum. Myocyte quantitative analyses revealed a gradual increase in vacuolar area/total cell area ratio and in collagen fibril deposition inside the vacuoles from 2 to 12 weeks post-infarction. Related to the remote zone, the increase in cell width of myocytes located in and adjacent to the border zone demonstrated cellular hypertrophy. These results indicate the occurrence of cardiomyocyte remodelling mechanisms in the border zone and adjacent regions of infarcted myocardium. It is suggested that the vacuoles represent plasma membrane invaginations and/or dilatations of T-tubular structures.