Evaluation of steroidogenic enzymes in a model of follicular persistence in dairy cows

CATTANEO MOREYRA ML; GAREIS NC; HEIN GJ; ANGELI E; ORTEGA HH; SALVETTI NR; RODRÍGUEZ FM; REY F

Mar del Plata, Buenos Aires Argentina.

Congreso; Reunión Conjunta SAIC, SAI, FAIC, SAFIS 2022. LXVII Reunión Anual de la Sociedad Argentina de Investigación Clínica (SAIC). 16 al 19 de noviembre de 2022.; 2022

SAIC

In dairy cows with cystic ovarian disease, steroid hormones andprotein levels of steroidogenic enzymes have been reported to bealtered. Furthermore, in cows with ovarian follicular persistence, alteredconcentrations of estradiol in serum and follicular fluid wereobserved. Therefore, we aimed to evaluate the protein expressionof enzymes involved in the synthesis of steroid hormones (StAR,CYP19, CYP17 and 3β-HSD) in ovarian tissue of cows with follicularpersistence. Holando Argentino cows with healthy reproductivetract (n=25) were subjected to estrous cycles synchronization with aG6G-Ovsynch protocol. While cows of the control group (CG, n= 5)were only synchronized, 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 with progesterone intravaginally (P4). Finally,the ovaries were obtained by bilateral ovariectomy. Histologicalovarian sections were used for the indirect immunohistochemistryto localize and quantify in situ protein expression of StAR, CYP19,CYP17 and 3β-HSD in persistent and control follicles. Protein expressionof CYP17 in theca cells and StAR in granulosa and thecacells was similar in the analysed groups (p>0.05). Lower CYP19expression was detected in the P5 and P15 groups compared tothe control group (p<0.05). The expression of 3β-HSD was greaterin granulosa and theca cells in the persistent follicles of P15 groupcompared to follicles of P0 group (p<0.05). In addition, in granulosacells, a greater expression was detected in the P10 group comparedto the P0 group (p<0.05). These results show a local alteration of theenzymes involved in the steroidogenic pathway during persistence.Considering the results registered in cows with cysts, we could inferthat the alterations in CYP19 and 3β-HSD occur before the cystsdevelopment.