MESENCHYMAL-EPITHELIAL INTERACTIONS IN AN IN-VITRO MODEL OF NEONATAL MOUSE UTERUS

Stromal factors have been implicated in epithelial growth of the fetal and neonatal mouse uterus, as well as in uterine epithelial prolifera tion in the adult, In the neonate, uterine growth is independent but r esponsive to estrogen, while epithelial proliferation in the adult ute rus is hormonally regulated. A co-culture model was developed to study interactions between uterine epithelium and stroma, Uteri of neonatal mouse were enzymatically separated into epithelial and mesenchymal ce ll fractions, and these were cultured for 5 days on Millipore well ins erts, either separately or in co-culture on opposite sides of the inse rt membrane, When epithelial cells were grown atone, inclusion of seru m in the culture medium tripled the number of cells present after 3-5 days compared with serum-free medium, Go-culture in the presence or ab sence of serum resulted in a 5-fold increase in epithelial cell number after 5 days, Addition of estrogen had no significant effect on epith elial cell number regardless of the presence of mesenchyme, Epithelial cultures grown in medium conditioned by mesenchymal cells exhibited a n intermediate increase in cell number, We therefore conclude that ute rine mesenchyme from neonatal mouse produces a diffusible factor that enhances the growth of the overlying epithelium; however, whether the mesenchyme has a role in estrogen-stimulated epithelial proliferation has not been definitively ascertained.