CONICET | Buscador de Institutos y Recursos Humanos

Indairy cows with cystic ovarian disease, steroid hormones and protein levels ofsteroidogenic enzymes have been reported to be altered. Furthermore, in cowswith ovarian follicular persistence, alteredconcentrations of estradiol in serum and follicular fluid were observed.Therefore, we aimed to evaluate the protein expression of enzymes involved inthe synthesis of steroid hormones (StAR, CYP19, CYP17 and 3β-HSD) in ovariantissue of cows with follicular persistence. Holando Argentino cows with healthyreproductive tract (n=25) were subjected to estrous cycles synchronization witha G6G-Ovsynch protocol. While cows of the control group (CG, n= 5) were onlysynchronized, cows of the experimental groups with 0 (P0, n=5), 5 (P5, n=5), 10(P10; n=5) and 15 days of persistence (P15; n=5), were also treated withprogesterone intravaginally (P4). Finally, the ovaries were obtained by bilateralovariectomy. Histological ovarian sections were used for the indirectimmunohistochemistry to localize and quantify in situ protein expression ofStAR, CYP19, CYP17 and 3β-HSD in persistent and control follicles. Proteinexpression of CYP17 in theca cells and StAR in granulosa and theca cells wassimilar in the analysed groups (p>0.05). Lower CYP19 expression was detectedin the P5 and P15 groups compared to the control group (p<0.05). Theexpression of 3β-HSD was greater in granulosa and theca cells in the persistentfollicles of P15 group compared to follicles of P0 group (p<0.05). Inaddition, in granulosa cells, a greater expression was detected in the P10group compared to the P0 group (p<0.05). These results show a localalteration of the enzymes involved in the steroidogenic pathway duringpersistence. Considering the results registered in cows with cysts, we couldinfer that the alterations in CYP19 and 3β-HSD occur before the cysts development.

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