Endometrial Response to Sexual Steroids as Assessed by Prostaglandin F2α Output in Explant Culture and Hormone Receptor Expression

Abstract

The objective of this study was to evaluate the endometrial response to sexual steroids in organ culture using two means: prostaglandin (PG) F_2α output in medium culture and steroid receptor immunoexpression in tissue. Human endometrium samples were classified in homogeneous and heterogeneous proliferative or secretory subsets. In proliferative endometrium explant culture, progesterone (10^–7 M) induced a significant decrease in PGF_2α output, but this was not the case in secretory endometrium, whereas no significant effect of estradiol (10^–8 M) was observed. Before culture, homogeneous and heterogeneous proliferative endometrium presented the same pattern of estradiol receptor (ER) and progesterone receptor (PR) expression evaluated by quantitative immunocytochemistry. After culture, immunoreactive ER and PR were detected on the explant. PR immunoexpression rates after culture were lower than before culture in glands on homogeneous proliferative and in stroma on heterogeneous proliferative endometrium explants without in vitro steroid addition. In secretory endometrium, no significant difference was observed between ER or PR immunoexpression rates before culture and after culture. These results provided the hormonal receptivity status of endometrium after culture and will thus serve as a reference for evaluating in vitro steroid effects on endometrium explants. Our preliminary results suggest that cultures of endometrium explants are a valid model for studying the effects of hormonal treatment on homogeneous as well as heterogeneous endometrium. These data could be particularly relevant for evaluating the potential response to hormone stimulation and treatment of endometria sampled in perimenopausal patients.