The normal and abnormal heart development: participation of extracardiac cell population.

Abstract

The purpose of the current study was the elucidation of the neural crest (NC) participation in the abnormal heart development after retinoic acid (RA) and ethanol treatment. The chick embryos were treated by 0,2-0,25 ml 50% ethanol at 72 hours of incubation and also by 1 mkg of all-trans RA at 15 stage. The macroscopic study of the hearts of the normal and treated embryos, hearts after whole staining for sulfated glycosaminoglycans, the histological and lectinhistochemical study of serial sections were carried. The phenomenon suggesting for the participation of NC in the abnormal heart development was the level of migration of dense mesenchyme originated from NC, its movement was delayed. As a result the dense mesenchyme was located more distal than in normal in both models. The decrease of apoptotic processes in the conus and trunk of the heart, the abnormal development its endocardial cushions as well as atrioventricular cushions were the indirect confirmations. RA and ethanol caused the diminish of endocardial cushions growth, suppressed the synthesis of glycosaminoglycans, mesenchyme cells and cardiomyocytes proliferation. One of the important mechanisms of abnormal development is the changes of the ex-tracelullar matrix properties