Identificação de receptores hormonais na placenta e avaliação do efeito da hormonioterapia em éguas com placentite

Abstract

The aim of this study was to identify the expression of progesterone receptors, alpha (REα), beta (REβ) receptors and estrogen related-receptor gamma (REγ), and aromatase expression in placenta of mares with ascending placentitis treated with different hormonal therapies, as well as the evaluation of leptin expression and its receptor in the placenta of healthy mares. The first study aimed to evaluate the presence of leptin and its receptor in the placenta at term, as well as leptin concentrations during pregnancy and after delivery. Eight (8) mares, crossbred Crioulo, with healthy pregnancies were used in the study. Placental fragments were collected to evaluate the immunolocalization of leptin and its receptor by the immunofluorescence technique. Serum levels of leptin from the 8th month of gestation up to 24 hours postpartum were also performed. Expression of leptin and its receptor in the microcotilednary epithelium and areolar region were identified, characterizing an autocrine and paracrine function of leptin in equine placenta. In the second study, the aim was to describe the expression and quantification of progesterone (PR) receptors, estrogen receptors α (REα), β (REβ) and estrogen-related receptor γ (REγ), and aromatase in the placenta of mares with ascending placentitis treated with different hormonal therapies. Twenty-three (23) pregnancies of twenty (20) crossbred Crioulo mares were used, the mares had induction of experimental ascending placentitis at 300 days of gestation, and were treated with different hormonal therapies. The groups was formed by control group, without induction of placentitis (n=6), no tretament group (with placentitis induced but without tretament n=3); trimetoprim+sulfamethoxazole with flunixim meglumine and hormonal therapy with altrenogest (n=6); trimetoprim+sulfamethoxazole with flunixim meglumine and hormonal therapy with altrenogest and estradiol cypionate (n=4); and trimetoprim+sulfamethoxazole with flunixim meglumine and hormonal therapy with estradiol cypionate (n=4). Consistent immunostaining of progesterone, α, β and γ estrogen receptors was observed, and also aromatase, all the immunostaining with predominance in the cytoplasm of the microcotyledons cells and areolar region of chorionic epithelium. Mares with placentitis on estradiol cypionate therapy demonstrated higher gestation length and quantification of aromatase in the placenta. The mares with altrenogest therapy have demonstrated shorter gestational length, and least immunostaining for α oestrogens. Meanwhile, mares without treatment and those with associated altrenogest and estradiol cypionate therapy have demonstrated increased immunostaining to progesterone receptors in the placenta.