MORPHOLOGICAL AND IMMUNOHISTOCHEMICAL DIFFERENTIATION PATTERNS OF RABBIT UTERINE EPITHELIUM IN-VITRO

We describe morphological and immunohistochemical changes of uterine e pithelium from immature rabbits in vitro in response to hormonal treat ments, using a matrix-coated semipermeable filter. These investigation s were compared to in vivo studies of uterine epithelium from immature rabbits treated with estrogen and/or progesterone. In vitro, polariza tion of the epithelium seems to be best developed under progesterone d ominance, and the pattern of cell organelles is similar to those seen in vivo. Two types of apical protrusions could be observed in cultures treated with progesterone, some shaped like domes, containing cell or ganelles, and some irregular in shape with small lucent vesicles. Both types of apical differentiation are typical for the in vivo situation . In vitro, estrogen leads to a more pseudostratified growth pattern o f the cells. They develop apical protrusions with big vesicles probabl y containing mucin, as in vivo. Treatment with both steroid hormones l eads to a heterogeneous response of the uterine epithelial cells in cu lture, some cells responding more to the estrogen, others to the proge sterone whereas in vivo the progesterone-dominant features are obvious . Immunohistochemistry of uteroglobin in monensin-treated cultures giv es evidence for uteroglobin secretion in all cultures, but to a lesser extent in the untreated, and this is strongly increased in cultures t reated with estrogen and progesterone. These results correspond to obs ervations made in vivo. This in vitro cell culture method seems theref ore to provide a useful model for investigating the regulatory mechani sms of sexual steroid hormones and the cell biology of uterine recepti vity.