IGF system: Involvement in the ovarian follicular persistence in cow

RODRIGUEZ, F.M.; HUBER E; GAREIS N; STASSI, A.F.; SALVETTI NR; ORTEGA HH; REY F

Mar del Plata

Congreso; LXI 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; 2016

Sociedad Argentina de Investigación Clínica (SAIC).

Ovarian functions are controlled by several hormones asinsulin-like growth factor (IGF) system. It has been postulatedthat alterations in IGF system would be involved in cystic ovariandisease (COD) development. The aim of this study was to evaluatethe role of members of IGF system that were altered in COD, inthe establishment of bovine persistent ovarian follicles. Thus, IGF1,its receptor IGFR1, the binding protein IGFBP4 and the hydrolyticenzyme PAPP-A were evaluated in ovarian samples. Estral cyclesof non-lactating Holstein cows (n=25) were synchronized and then,animals were divided in five groups: control (without hormonaltreatment) and 0 (day of ovulation), 5, 10 and 15 days of follicularpersistence. Persistent follicles were obtained from cows treatedwith long-term subluteal progesterone administration using anintravaginal progesterone-releasing device. Concentrations of IGF1determined by radioimmunoassay and levels IGFBP4 evaluatedby western blot (WB) in follicular fluid (FF), were similar in all thestages of persistence and preovulatory follicles. IGFR1 expressionanalyzed by immunohistochemistry (IHC) was higher in the granulosaof persistent follicles of P0, P10 and P15 (p <0.05) than inpreovulatory follicles. IGFBP4 protein expression analyzed by IHCwas greater in all the stages of persistence than in preovulatoryfollicles (p<0.05). No differences were detected by WB in PAPP- Asecreted to FF in all persistent follicles compared with preovulatoryfollicles. Results of this study showed that several changespreviously determined in animals with COD are presented at initialstages of follicular persistence. These alterations in IGF systemaffect the normal ovarian follicular development and could lead tothe development of the COD. These data confirm an essential roleof the IGF system in the pathogenesis of COD in cattle.