DETECTION OF INTERLEUKIN-1, INTERLEUKIN-6, AND TUMOR-NECROSIS-FACTOR-ALPHA IN THE UTERUS DURING THE 2ND-HALF OF PREGNANCY IN THE MOUSE

This study demonstrated interleukin-1 (IL-1), IL-6, and tumor necrosis factor-alpha (TNF-alpha) in the mouse uterus during the second half of pregnancy (days 9-18). High concentrations of IL-1-alpha-mRNA and bioactive IL-1 were detected between days 12-17. IL-1 bioactivity decreased to very low levels as pregnancy approached parturition. IL-6 mRNA was detected from days 9-18, and IL-6 bioactivity approximately paralleled IL-1 bioactivity. High levels of IL-1 and IL-6 bioactivity, but not IL-1 or IL-6 mRNA, were detected in the placenta between days 12-17. Placental IL-1 and IL-6 also decreased to low levels near parturition. TNF-alpha-mRNA was expressed from days 9-17, and a peak of TNF-alpha bioactivity was detected during the period immediately before parturition. TNF-alpha-mRNA and TNF-alpha bioactivity were not detected in the placenta. On day 18, the day of parturition, the concentrations of IL-1, IL-6, and TNF-alpha-mRNA were very low relative to those on other pregnancy days. Immunocytochemistry with antibodies to IL-1, IL-6, and TNF-alpha was used to confirm the presence of all three cytokines in uterine cells throughout the second half of pregnancy. Those data showing the kinetics of cytokine production during fetal development raise the possibility that cytokines and cytokine-induced mediators modulate cellular events during the late stages of pregnancy in the mouse.