Immunolocalization of insulin-like growth factor binding protein-2 (IGFBP-2) in bovine cystic follicles

RODRIGUEZ F; BALDI, C; ORTEGA, HH; BARBEITO, CG; GIMENO, EJ; REY F

Brazil

Congreso; Encontro Nacional de Patologia Veterinaria; 2009

A widespread reproductive disorder in cattle is the cystic ovarian disease (COD). The mechanism leading to their development was proposed to be of multifactorial etiology. Although it is widely accepted that a dysfunction of the hypothalamic-pituitary-gonadal axis is an important etiological factor, several reports have discussed the association between COD and growth factors in different species. The insulin-like growth factor (IGF) system has already been shown to play a key role in the regulation of proliferation and differentiation of granulosa and theca cells. IGF binding proteins (IGFBPs) regulate the availability of IGFs to their target cells by either inhibiting or potentiating their action and also can sequester extracellular IGFs and hence reduce their bioavailability. Two mechanisms have been suggested by which availability of IGFs can be modified; through the activity of specific IGFBP proteases, or by changes in the IGFBPs expression. In previous studies we detected a significant low expression of IGFBP-2 in follicular fluid and evidence exists to suggest that could be due, in part, to changes in local synthesis. In the present study we proposed to analyze the mRNA expression of IGFBP-2 by RT-PCR using GAPDH as housekeeping. Moreover, we assessed the protein localization by immunohistochemistry. Ovaries of cows proceeding of a local abattoir were collected and dissected. Healthy follicles were classified into small (<