Gestational age-dependent effects of lipopolysaccharide on prostaglandin production by murine decidual caps

We sought to determine whether the gestational age of the pregnant mouse ha d any relationship with its lipopolysaccharide (LPS) responsiveness. Murine decidual caps from days 13, 15 and 17 of gestation (term is day 20) were d issected out, placed in inserts and equilibrated in media overnight. The fo llowing day, media were removed, replaced with fresh media (+/-LPS at 10 mu g/mL). After LPS stimulation (24 h), prostaglandin (PG)E-2 production by de cidual caps from days 13 and 15 increased by 80-fold and 5-fold, respective ly. PGF(2 alpha), 6-keto-PGF(1a) and TxB(2) production also increased. Day 17 decidual caps were unaffected by LPS, pregnant mice inoculated i.p. with LPS (50 mug) at day 13 of gestation induced 100% delivery within 24 h. How ever, mice treated at days 15 and 17 had an equal occurrence of premature d elivery or fetal resorbtion. This change in LPS responsiveness may indicate changes in the fetal-maternal immune system in late pregnancy. (C) 2001 Ha rcourt Publishers Ltd.