Protective effect of progesterone (P) on pregnancy loss due to LPS

J. AISEMBERG, C. VERCELLI, M. WOLFSON, S. BILLI, M.L. RIBEIRO, M. FARINA, A.M.FRANCHI.

Orlando

Congreso; 29th Annual Meeting of The American Society for Reproductive Immunology; 2009

Maternal infections are cause of abortion and preterm labor in humans but their mechanisms are not clear. Septic abortion is associated with a range of severity of inflammation, but only a small proportion of women have clinical signs of infection. We have developed a murine model of embryonic resorption (ER) where the administration of lypopolisaccharide (LPS) is designed to mimic, as closely as possible, the clinical consequences of septic abortion. LPS, in only one dose, produces 100% of ER at 24h after having been injected. LPS also causes systemic effects in the mother such as diarrhea, piloerection and bent posture, but is not fatal. The implantation sites are expulsed by the mother on day 9 and no evidence of gestation is found by day 12 (Ogando D, 2003). LPS treatment produces a significant increase in uterine nitric oxide (NO) production and iNOS expression. Besides, the administration of the endotoxin causes an augmentation uterine PGs synthesis, an increase in COX-2 messenger and in the nitration of this enzyme (Aisemberg J, 2007). Anandamide (AEA) is an endogenous analogue of THC, the principal psychoactive component of marijuana. Low levels of plasma (AEA) are associated with a successful pregnancy in women. LPS, in vitro, is able to increase uterine AEA synthesis and to decrease its degradation. We also found that AEA induces embryonic resorption in vivo and mediates LPS-induced NO synthesis (Vercelli C, 2009). Progesterone (P), one of the main molecules that maintain pregnancy in mammals, is involved in all of the characteristic events of pregnancy. The aim of this study was to evaluate progesterone participation in septic abortion.