Marcadores de implantación embrionaria alterados por hiperandrogenismo fueron restaurados por tratamiento con metformina

LUCHETTI, C. G.; MIRKO, E; SZEKERES-BARTHO, J; PAZ, DANTE; MOTTA AB

Buenos Aires

Congreso; XX Reunión Bienal Asociación Latinoamericana de Investigadores en Reproducción Humana-; 2007

Asociación Latinoamericana de Investigadores en Reproducción Humana-

Metformin  (M) is an insulin-sensitizing drug used in the treatment of polycystic ovary syndrome, which mechanism of action is still unknown. In previous studies we have observed that M prevented embryo resorption (ER) caused by hyperandrogenization with dehydroepiandrosterone (D). The purpose of this work was to study: 1) the morphology of the implantation sites  (IS); 2) the localization of the enzymes cyclooxygenase-2(COX: responsible of prostaglandin synthesis which in turn modulate the uterine contractility) and nitric oxide synthase activity (NOS); 3) the nitrites concentration (NO, as oxidant specie); 4) the expression of progesterone-induced blocking factor (PIBF, regulator of cytokine production); and 5) serum levels of interleukin 6 (IL6). The experimental groups were: uterine tissues from 8 day-pregnant mice (implantation day: 5, treatment days: 6 and 7) treated as follows: C (control), D (sc 60 mg/kg body weight) and D+M (M:250 mg/kg oral by canula) were used for morphological studies (hematoxylin-eosin); immunohystochemistry for iNOS, eNOS, COX and PIBF expressions and nitrites quantification by the Griess assay. Serum IL6 was quantified by ELISA. n=6/group. We found that the IS of D treated mice suffered from disarticulation of decidual matrix with larger lacunae than C mice. M restored the morphology. The iNOS, eNOS and COX expressions were located in lacunae and syncytiotrophoblast areas in all the experimental groups We observed that D caused a significant increase in the expression of the three enzymes, which was revented by M (COX: C 10.3+0.4;D 28+1;D+M 9.7+0.4 - iNOS: C 7.5+0.3;D 20+1;D+M 13.1+0.3- eNOS: C 8.3+0.2;D 13.1+0.3;D+M 7.1+0.2, % of marked area. Nitrites were increased by D (450±25 vs C 296±25nmol/mg protein) meanwhile M prevented this effect (346±25nmol/mg protein). Uterus from D group did not show presence of PIBF, however, in C and D+M groups, PIBF was located in trophoblast and its surrounding decidua. IL6 levels were disminished in D group (1,7±0,9 vs C 4,8±0,9pmol/ml serum) and were restored in  D+M group (5,7±0,3pmol/ml serum). We can conclude that M prevents ER caused by D hyperandrogenyzation, providing uterine quiescence (by regulation of COX expression), protecting the tissue from oxidation (by diminishing NOS expression and nitrites) and restoring the PIBF levels (implantation marker) and IL6 levels (Th2 cytokine).