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

LEIVA CJ, DURANTE LI, MATILLER V, BELOTTI EM, DÍAZ PU, SALVETTI NR, ORTEGA HH, MARELLI BE.

Mar del Plata. Buenos Aires. Argentina.

Congreso; Reunión anual de sociedades de Biociencias: SAIC, SAFE, SAP, AACYTAL, NANOMED-ar, HCS. 13-16 de noviembre de 2019.; 2019

SAIC

Follicular persistence is a component of cystic ovarian disease (COD) in dairy cows. Numerous events occur during folliculogenesis and an adequate supply of nutrients is necessary. Although growth hormone (GH) has been associated with follicular development, little is known about its function in ovarian diseases. The aim of this study was to evaluate the immunoexpression of GH receptor (GHR), the intracellular signal transduction pathway proteins Janus kinases (JAKs) and the signal transducers and activators of transcription (STATs) by immunohistochemistry, during follicular development in the ovary of cows with induced persistence. The experimental model was performed with an intravaginal progesterone device to get subluteal plasma concentrations of the hormone, obtaining anovulatory persistent follicles. Cows were 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 proestrous to obtain preovulatory dominant follicles (C; n= 5). In granulosa cells, the immunoexpression of GHR decreased during folliculogenesis as follicular growth progressed both in control and persistence groups. In theca interna, the expression was lower in antral follicles of C group than in antral follicles of all persistence groups (p<0.05). Also, in granulosa, total JAK2 was lower in all 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 group respect to persistent follicles of P10 and P15 (p<0.05). Phosphorylated JAK2 was lower in persistent follicles as persistence days progressed. Total and phosphorylated STAT5 showed no differences between groups (p>0.05). In granulosa, phosphorylated STAT3 was lower in P10 compared to P0, P5 and P15 groups (p<0.05). These alterations in the expression of GHR and the GH signaling pathway proteins in follicular persistence may be associated with COD pathogeny.