Study of morphology and deciduomal proteins of hamster endometrial cells during in vitro decidualization

The objective of this study was first, to examine whether the morphological characteristics of deciduomal cells are correlate to differentiation or just to hyperplasia and hypertrophy, and second, to examine whether the deciduoma-associated proteins (DAPs) are expressed consistently during decidualization in vitro and in vivo. In vitro decidualization was implemented by dissociated cell culture of Day-4-pseudopregnant endometrium. The morphology of these cultures was compared with that of undifferentiated cultures of fetal hamster fibroblast. They appeared similar morphology in the stellate shape, the binucleation and the intracellular fibers. The DAPs were identified by comparing the electrophoretic maps of one-day cultures of decidualized and nondecidualized endometrium from unilaterally scratched Day-6-pseudopregnant animals. Analysis of cytosol fraction by SDS-PAGE demonstrated the presence of four DAPs. That only one of them was growth-associated, which was concluded from its increasing expression in fetal fibroblast, and that all of them were not endometrium-specific as evidenced by their presence in other tissues. By examining their expression during in vitro decidualization, we found that timing of the DAPs' expression in vitro was not consistent with it in vivo. These results indicate that some morphological characteristics which were accustomedly used to mark deciduomal cells may relate to hyperplasia and hypertrophy instead of differentiation, and that the in vitro and the in vivo decidualization are not identical.