Morphological analysis of degeneration and regeneration of syncytiotrophoblast in first trimester placental villi during organ culture

We have recently shown using dansyl-L-lysine exclusion studies that therelease of human chorionic gonadotrophin (HCG) in conjunction with L-lactate dehydrogenase (LDH) from first trimester villi during organ cultureis symptomatic of syncytiotrophoblast degeneration. The purpose of thisstudy was to examine chorionic villi at the ultrastructural level in orderto determine events occurring during organ culture. The tissue was sampledafter 0, 24, 48 and 120 h in culture and processed for electron microscopy.In addition to confirming the previously recorded syncytial degeneration,the electron micrographs showed clearly the generation of a newsyncytiotrophoblast layer. The new layer, derived from differentiatingcytotrophoblast cells, was largely formed by 48 h and was maintained for atleast 120 h in culture. This study demonstrates a model which provides anopportunity to study the differentiation of cytotrophoblast cells whilstthey retain their anatomical relationships within the villous structure.