Interleukin-1 beta and the endometrium: an inhibitor of stromal cell differentiation and possible autoregulator of decidualization in humans.

Interleukin-1 beta (IL-1 beta), which modulates cell proliferation and differentiation in a number of cell types, is present in human endometrial stromal cells. However, both the function of IL-1 beta in endometrium and the factors that modulate its expression in endometrial stromal cells are unknown. To examine the effects of IL-1 beta on decidualization, human proliferative endometrial stromal cells were cultured for 12 days in medium (Dulbecco's Modified Eagle's medium with 2% fetal bovine serum) containing 1 microM medroxyprogesterone acetate, 10 nM estradiol, and 1 microM prostaglandin E2 (PGE2) with and without IL-1 beta (17 pg/ml). Morphologic changes as well as release of prolactin (PRL) and insulin-like growth factor binding protein-1 (IGFBP-1) were used as markers of decidualization. Morphologic analysis of cells exposed to IL-1 beta revealed incomplete decidualization. In addition, cells exposed to IL-1 beta released 40% less PRL and 85% less IGFBP-1 than cells cultured in the absence of IL-1 beta, and the PRL mRNA content of the IL-1 beta-exposed cells was decreased by 68%. A possible role for ovarian steroids in the modulation of IL-1 beta expression in the endometrium is suggested by the increase in IL-1 beta mRNA that occurs in late secretory endometrium and by the induction of IL-1 by estrogen and progesterone in the mouse uterus.(ABSTRACT TRUNCATED AT 250 WORDS)