Time-lapse study of normal human trophoblast in vitro.

Time-lapse photographic observations of normal human trophoblast in vitro were made possible through the development of a new technique that allows for prolonged trophoblast culturing without stromal growth. Y body fluorescence and determinations of human placental lactogen (hPL) were used to confirm the specificity and viability of the cells in culture. Epithelioid cells (cytotrophoblast) with agranular cytoplasm, binucleated moderately granulated cells, and multinucleated heavily granulated syncytial masses were observed. The cytotrophoblast was observed in mitosis, whereas the syncytium showed strand formation and reabsorption, along with mass movement of cells at time of confluency. This technique should stimulate a renewed interest in the in vitro studies of normal human trophoblast.