Fibronectin localization in the mouse embryo from the blastocyst stage to the egg cylinder stage in vitro.

Abstract

Med., 1988, 154 (3), 261-269 Fibronectin has the characteristics of adhesiveness and cell migration promotion which may play important roles in embryo implantation. Using the direct and indirect immunofluorescence techniques, we found fibronectin on the blastocyst, and the trophoblast cells of the egg cylinder stage embryo, especially at the sites of cell spreading, as well as the inner cell mass. The results show that (i) fibronectin is used for the initial cell attachment to the plastic dish, and (ii) during the course of embryo growth in vitro, the trophoblast cells spread over the plastic dish in the area of cells which contain many granules of fibronectin.fibronectin ; mouse embryo ; ovum implantation ; trophoblast ; immunofluorescent antibody technique Among the characteristics of fibronectin, the adhesiveness and the cell migration promotion may facilitate the embryo implantation.Although it was reported that fibronectin did not appear in the mouse embryo until the late blastocyst stage, (Zetter and Martin 1978; Wartiovaara et al. 1979), we found fibronectin in the mouse embryo from the two cell stage (Yohkaichiya et al. 1988), and our findings indicate that fibronectin is not abruptly produced just before the embryo implantation, but it is gradually produced along the course of embryo growth at least from the two cell stage. In order to investigate the role of fibronectin at the time of embryo implantation the techniques of direct and indirect immunofluorescence were used to locate the fibronectin on the delicately fixed mouse blastocysts and the egg cylinder stage embryos which were cultured in vitro from the blastocyst stage. The results suggest that the adhesiveness of fibronectin may help the embryo to attach to the uterus endometrium and the