Effect of Anandamide and Lipopolysaccharide on early murine pregnancy

CLAUDIA VERCELLI; JULIETA AISEMBERG; SILVIA BILLI; MARCOS CERVINI; MARÍA LAURA RIBEIRO; ANA MARÍA FRANCHI

Tihany, Hungría

Simposio; 16th Annual Symposium on the Cannabinoids; 2006

International Cannabinoid Research Society (ICRS)

Nitric oxide (NO) fulfils important functions during pregnancy and has a role in implantation, decidualization, vasodilatation and myometrial relaxation. However, at high concentrations, such as those that are produced in sepsis, NO has toxic effects as it is a free radical. Our previous results indicate that LPS, an integral part of the outer membrane of Gram negative bacteria, is capable of producing embryonic resorption in mice due to NO increased production not only in uterus but also in decidua. Recent research has revealed that LPS induces AEA synthesis in murine macrophages. The aim of the present work was to determine the effect of LPS and AEA on early murine pregnancy. On day 7 of pregnancy female mice were killed by cervical dislocation and uterus and decidua were separated in each implantation site. Uterus was then incubated for 24 h in the presence of a) LPS (1 ug/ml), b) AEA (10-7M) and c) LPS + AM251 (20uM) (cannabinoid type 1 (CB1) receptor antagonist) and NO as NO3- plus NO2- was measured in culture supernatants. Both LPS and AEA were capable of increasing NO levels and, NO production induced by LPS was inhibited when uterus was incubated in the presence of AM251. We also determined AEA synthesis (conversion of [14C]-arachidonic acid and ethanolamine in [14C]-AEA) and the expression of the fatty acid amide hydrolase (FAAH–the enzyme responsible for hydrolysis of AEA) by western blot in the presence or absence of LPS. Treatment with the endotoxin increased AEA synthase activity and seemed to decrease FAAH expression. These results and the inhibition of LPS-induced augmentation of NO synthesis by AM251 suggest that AEA could be an intermediate in LPS effect. Prostaglandins (PG) and NO are intimately involved in the mechanism of parturition. NO maintains uterine quiescence during pregnancy whereas PGs are involved in eliciting contractions of uterine smooth muscle. PG biosynthesis is catalized by ciclooxygenase (COX) which exists in tow isoforms: COX-1 and COX-2. Because LPS is known to induce high levels of PGs in several tissues, we determined the levels of PGE2 in the uterus of female mice on day 7 of pregnancy in the presence of LPS and LPS+AM251. We observed that the high levels of PGE2 induced by LPS were decreased by AM251. These results suggest that the synthesis of the two main molecules involved in LPS-induced embryonic resorption (NO and PGs) may be mediated by AEA.