COMPARISON OF PROGESTERONE AND INFLAMMATION PARAMETERS IN SUBFERTILE YOUNG AND OLD MARES

MARINONE, ANA INÉS; HERRERA JUAN; AGUILAR, JAVIER; FUMUSO ELIDA; CANTATORE, SOFIA E; LOSINNO, LUIS; CADENAZZI, GABRIELA; HERRERA, MARCELA; REDOLATTI, CECILIA; MUTTO, ADRIAN; MARINONE, ANA INÉS; HERRERA JUAN; AGUILAR, JAVIER; FUMUSO ELIDA; CANTATORE, SOFIA E; LOSINNO, LUIS; CADENAZZI, GABRIELA; HERRERA, MARCELA; REDOLATTI, CECILIA; MUTTO, ADRIAN

Tours

Workshop; International Congress on Animal Reproduction ICAR; 2016

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Mares are selected as embryo transfer donors based on their genetics or sports performance, but not on their fertility. It is known that old mares (OM) have lower reproductive efficiency than young mares (YM). A great amount of works on subfertility compares YM with OM, but little has been described regarding subfertileYM. In this study, two groups of subfertile mares were selected based on reproductive history. Twenty two YM (aged 3-10) and nineteen OM (aged 14-26) were evaluated to compare their plasma progesterone levels,endometrial inflammation and progesterone receptors. This study was performed in a Silla Argentino stud farm located in Tandil, Buenos Aires Province, Argentina. During two breeding seasons, blood samples and endometrial biopsies were taken on day 8 post-ovulation, after each flushing for embryo recovery. A total of 97 plasma samples from YM and 112 from OM were analyzed by radioimmunoassay. Statistical analysiswas performed through PROCGENMOD. Endometrial biopsy sections were stained with hematoxylin-eosin to evaluate the presence of inflammatory cells in stratum compactum and spongiosum. Polymorphonuclear (PMN) and Mononuclear cells (MN) count ?in 20 fields (100X) on each biopsy? was conducted by two operators. Statistical analysis was performed through ANCOVA. Progesterone receptors in endometrial biopsies were evaluated by immunohistochemistry assay on glandular and luminal epithelium, and stratumcompactum and spongiosum. Samples were observed by two operators to detect the number and intensity of receptors immune reactivity in 10 fields (100X) of each endometrial area. Statistical analysis was performed through mixed logistic regression. Plasma progesterone concentrations were similar in both groups (p=0.25). Endometrial inflammation, based on PMN count, exhibited similar patterns in both mares groups (p=0.69). Differences were found for MN, where OM showed higher amount, both within the stratum compactum (p=0.01) and the stratum spongiosum (p=0.02). Progesterone receptors evaluation also showed differences between groups. Luminal epithelium immunostaining of OM was higher (p<0.05) and glandular epithelium showed a tendency for an increase (p<0.06) when they were compared with the stratum compactum and spongiosum. The immune reactivity was also higher in luminal epithelium compared to other areas (p<0.05), while YM presented similar reactivity in all endometrial areas (p>0.10). In conclusion, these findings mightsuggest that young subfertile mares differ in some endometrial immune and endocrine parameters compared with old subfertile mares.