VEGF system expression as important intraovarian component in the follicular persistence associated with bovine COD

BARAVALLE ME; VELAZQUEZ M; ORTEGA HH; BELOTTI M; SALVETTI NR; STASSI, A; PERALTA, B; BARAVALLE ME; VELAZQUEZ M; ORTEGA HH; BELOTTI M; SALVETTI NR; STASSI, A; PERALTA, B

Mar del Plata

Congreso; XI Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica (SAIC), LXIV Reunión anual de la SAI; XLVIII Reunión anual de la SAFE; VII Reunión anual de la NANOMEDAR; V Congreso Nacional de la AACYTAL; 2016

Sociedad Argentina de Investigación Clínica (SAIC).

Cystic ovarian disease (COD) is one of the mostimportant causes of reproductive failure in cattle. Cause anovulation andcontinuous growth of follicles to excessive diameters that fail to ovulate,persist and then interfere with normal ovarian function. Angiogenesis is acomplex process regulated by angiogenic factors. Vascular Endothelial GrowthFactor (VEGF) is one of the most important pro-angiogenic factors and VEGF Receptor-2(VEGFR2) is the major mediator of the angiogenic effects of VEGF. The VEGFAprotein expression in both the theca (TC) and granulosa cells (GC) increasessignificantly as follicles grew and matured. Thus we hypothesized that thealteration of these factors may contribute to the follicular persistence and pathogenesisof COD. The aim of this study was to examine VEGFA and VEGFR2 expression by immunohistochemistryin ovarian follicular structures during the development of follicularpersistence induced in cows by long time progesterone administration. A lowdose of progesterone was administered (n=5) for 0 (ovulation time) and 5, 10,and 15 days after the expected day of ovulation: groups P0, P5, P10, and P15,using an intravaginal progesterone-releasing device. Control cows (group C) receivedno additional hormonal treatment. Results showed changes in VEGFA and VEGFR2 expressionalong folliculogenesis, in GC and TC in the different stages of follicularpersistence (p<0.05), in P0 and P15 for VEGFA and in all groups for VEGFR2. Whengroups were compared, increased expression of VEGFA and VEGFR2 in TC wasdetected in persistent follicles from P0 in relation to the antral folliclesfrom C group (reference structure) (p<0.05). The results of this studysuggest that excessive growth of persistent follicles depends on developedvasculature in the ovary, showing its participation throughout the ovarianfolliculogenesis and considering the experimental model, its relationship withthe pathogenesis of bovine COD.