Isolation and culture of hamster ectoplacental cone trophoblasts: an in vitro study on the cell types and their growth pattern.

The method of isolation of trophoblast cell types from ectoplacental cone of hamster embryo of day 8 post coitum (plug day as day 1) and examination of their growth pattern in vitro is presented in this study. Based on their size, three types of trophoblast cells were identified. (1) the smaller cells having clear cytoplasm formed the major portion (70% to 80%) of the total cell population (2) moderately bigger cells having mono or binucleated appearance and containing minute granules in the nuclear region formed 5% to 10% and (3) extra large and multinucleated cells shared 10% to 20% of the total cell number. While the smaller and slightly bigger cells showed moderate growth the larger ones had extensive growth and were seen to acquire different shapes on extending the duration of culture, such as fusiform, dumb-bell, polygonal, rectangular or flowery. The extremities of the cytoplasmic growth of these cells were seen to be thickened at one end giving the impression of a pad-like structure. The significance of these adaptations are not known at present.