PARENT SESSION
GROWTH FACTORS

Wednesday, August 4, 2004
10:30 AM–12:30 PM
Buchanan Courtyard

(664) PROGESTERONE PRODUCTION IN CATTLE PLACENTA UNDER THE INFLUENCE OF VEGF AND bFGF IN VITRO.

Campos, Danila¹, Artoni, Laura¹, Teixeira, Andrey³, Kfoury Jr, José Roberto¹, Miglino, Maria Angélica¹, Birgel Jr, Eduardo², Buratini Jr, José³, Machado, Ubiratan⁴, Papa, Paula ¹, ¹ Surgery Dept, Veterinary Medicine School, University of São Paulo, São Paulo, Brazil³ Dept. of Physiology, IB-UNESP, Botucatu, Brazil² Dept. of Large Animals Clinic, Veterinary Medicine School, University of São Paulo, São Paulo, Brazil⁴ Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil

ABSTRACT- Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are the most important growth factors regulating placental angiogenic process. Although the role of these heparin-biding proteins in vasculogenesis and angiogenesis is already well established, recent studies point towards growth factor modulatory effects in steroidogenic tissues. The aim of this study was therefore to evaluate the effects of VEGF and bFGF on progesterone (P₄) production from bovine placental cells in culture in order to elucidate whether these factors contribute to steroidogenesis and consequently to pregnancy maintenance. Bovine placentomes from days 90, 150, 210 of pregnancy and at term were obtained by cesarean sections. Under aseptic conditions, cells were mechanically dispersed, washed and centrifuged three times using D-MEM, supplemented with 5% fetal bovine serum and then cultivated in a 96-well plate at 37^oC under 5% CO₂ atmosphere. After 24 hours, medium was changed and growth factors were added at concentrations of 50 and 10 ng/ml for VEGF and bFGF, respectively. Samples of medium from control, bFGF, VEGF and bFGF plus VEGF were collected 24, 48 and 96 hours after growth factor addition. Following medium collection, wells were trypsinized and cells were used to measure protein content. Medium P₄ concentration was assessed by RIA using a standard commercial kit. At 24 hours of experiment, VEGF could increase P₄ production from placental cells on day 210 of pregnancy, while bFGF had a proliferative effect in these cells. In addition, VEGF and bFGF together induced an increase of P₄ production from placental cells at term. On the other hand, growth factors were not able to influence P₄ production neither cell proliferation on days 90^th and 150^th of gestation. These data suggest that placental cells may respond to VEGF and bFGF stimulation in different ways in dependence of pregnancy stage. The influence of VEGF and bFGF on placental cell proliferation and P₄ secretion indicates that these growth factors may also modulate placental development and function, contributing directly for bovine reproduction.

KEY WORDS: bFGF, progesterone, VEGF , bovine placenta