A quantitative study of the ventricular myoarchitecture in the stage 21-29 chick embryo following decreased loading.
A quantitative study of the ventricular myoarchitecture in the stage 21-29 chick embryo following decreased loading.
复制标题
对 21-29 期鸡胚负荷减少后心室肌结构的定量研究。
DOI：
10.1076/ejom.36.2.105.4775
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Clark,EB
中科院分区：
文献类型：
--
作者：
Sedmera,D;Pexieder,T;Hu,N;Clark,EB
在早期发育阶段，心室肌结构经历了从壁光滑的心管到充满海绵状小梁支柱网络的左心室和右心室的转变。我们测量了正常21-29期鸡胚和慢性维拉帕米窒息后心室肌特性的定量变化。形态学参数（致密层厚度，心室壁成分，孔隙率的不同层和小梁方向）进行了测定，从横向解剖灌注固定的心脏的扫描电子显微镜照片。通过微渗透泵，以每小时1 μ l的速度向第21阶段鸡胚的血管床中注入1 ng维拉帕米，直至第24、27和29阶段。从第24期开始，左心室致密心肌的厚度大于右心室。在第24和27阶段之间，厚度的增加是最小的，而主要呈放射状排列的小梁占总心肌质量的75%。从心室中心（70%）到致密心肌（0%），小梁间间隙与小梁（局部孔隙度）的比值降低。在维拉帕米处理的胚胎中，心脏较小，发育迟缓。致密心肌较正常心肌薄，小梁比例高于对照组。对照组和实验组的局部孔隙度值相似。负荷降低导致生长和形态发生延迟，表现为持续存在的小梁和较薄的致密心肌。胚胎心脏的泵血功能很大程度上是基于广泛发展的小梁与区域不同的属性。
During the early developmental period, ventricular myoarchitecture undergoes a transition from a smooth-walled cardiac tube, to left and right ventricular chambers filled with a sponge-like network of trabecular struts. We measured the quantitative changes of ventricular myocardium properties in normal stage 21-29 chick embryos and after chronic verapamil suffusion, which is known to decrease work load and decelerate ventricular growth. The morphologic parametres (compact layer thickness, ventricular wall composition, porosity of different layers and trabecular orientation) were determined from scanning electron micrographs of transversely dissected perfusionfixed hearts. A vascular bed of stage 21 chick embryos was suffused with 1 ng of verapamil at 1 pl per hour up to stages 24, 27 and 29 via a miniosmotic pump. From stage 24, the thickness of the compact myocardium in the left ventricle was greater than that of the right. The increase in thickness was minimal between stages 24 and 27, while the predominantly radially arranged trabeculae comprised up to 75% of total myocardial mass. The ratio of intertrabecular spaces to trabeculae (local porosity) decreased from the ventricular center (70%) towards the compact myocardium (0%). In verapamil-treated embryos, the hearts were smaller and showed delayed development. The compact myocardium was thinner than normal, and the proportion of trabeculae was higher than in controls. The local porosity values were similar in control and experimental groups. Decreased load resulted in delayed growth and morphogenesis, expressed as a persistence of trabeculae and a thinner compact myocardium. Embryonic heart pumping function is largely based on extensively developed trabeculation with regionally different properties.