Evaluation of growth hormone receptor and intracellular signal transduction pathway proteins in a follicular persistence model in cattle

LEIVA, C.J.M.; DURANTE, L.I.; MATILLER, V.; BELOTTI, E.M.; DÍAZ, P.; SALVETTI, N.R.; ORTEGA, H.H.; MARELLI B.E.

Mar del Plata

Congreso; Reunión Anual de Biociencia 2019; 2019

SAIC . SAFE . SAB . SAP. AACYTAL . NANOMED-ar . HCS

Follicular persistence is a component of cysticovarian disease (COD) in dairy cows. Numerous events occur duringfolliculogenesis and an adequate supply of nutrients is necessary. Although growthhormone (GH) has been associated with follicular development, little is knownabout its function in ovarian diseases. The aim of this study was to evaluatethe immunoexpression of GH receptor (GHR), the intracellular signaltransduction pathway proteins Janus kinases (JAKs) and the signal transducersand activators of transcription (STATs) by immunohistochemistry, duringfollicular development in the ovary of cows with induced persistence. The experimentalmodel was performed with an intravaginal progesterone device to get subluteal plasmaconcentrations of the hormone, obtaining anovulatory persistent follicles. Cowswere ovariectomized at the expected day of ovulation (P0) and at 5 (P5), 10 (P10)and 15 days (P15) of persistence (n=5). Control cows were ovariectomized in proestrousto obtain preovulatory dominant follicles (C; n=5). In granulosa cells, theimmunoexpression of GHR decreased during folliculogenesis as follicular growthprogressed both in control and persistence groups. In theca interna, theexpression was lower in antral follicles of C group than in antral follicles ofall persistence groups (p<0.05). Also, in granulosa, total JAK2 was lower inall follicular categories of the C group in relation to the persistence groups(p<0.05). In theca, total JAK2 was lower in antral follicles of the C grouprespect to persistent follicles of P10 and P15 (p<0.05). Phosphorylated JAK2was lower in persistent follicles as persistence days progressed. Total and phosphorylatedSTAT5 showed no differences between groups (p>0.05). In granulosa, phosphorylatedSTAT3 was lower in P10 compared to P0, P5 and P15 groups (p<0.05). These alterationsin the expression of GHR and the GH signaling pathway proteins in follicular persistencemay be associated with CODpathogeny.