Comparative study of the VEGF system temporal distribution in the bovine and canine placenta

Author(s)

José Eduardo Barbosa Marques Junior

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2006-11-24

Examining board members

Paula de Carvalho Papa; Ubiratan Fabres Machado; Maria Angélica Miglino

• Advisor: Paula de Carvalho Papa

Abstract

The VEGF family is known to be responsible for the angiogenesis increasing blood vessels number and permeability in the endometrial/placentary interface. A comparative study of VEGF system temporal distribution in canine and bovine placentas, which present very well described differences in structure and function, will contribute to better define the role of this system along pregnancy. Samples from placental belt of pregnant bitches (on days 20, 40 and 60) were collected as well as bovine placentomes samples (from days 90, 150, 210, 270 of gestation). All samples were frozen in liquid nitrogen and stored at -80º C until processed, or fixed in buffered formalin solution and embedded in paraplast using conventional procedures. Western Blotting for VEGF system quantification was carried out using specific antibodies combined to an amplification quimio-luminescence system: ECL®. Immunohistochemistry for canine Flt-4 demonstration was performed according to the ABC method using NovaRed® as chromogen. In the bovine placenta, VEGF demonstrate a higher expression in early gestation, which decreased at mid-gestation and remained so until term. Flt-1, KDR and Flt-4 demonstrated a constant expression in early and mid-gestation, and a decrease in the end of pregnancy. In the dog placenta, VEGF and Flt-1 proteins show an increased expression in early gestation, and a decreased expression at mid and late gestation; while KDR demonstrated an increased expression at early and mid-gestation, and a decreased expression near term. Flt-4 protein is localized in placental labyrinth, chorion and allantochorion. Similar expressions of these proteins in both species, that present considerable differences in placenta structure and function, suggest that VEGF system and Flt-4 play similar roles in the bovine and canine placenta. (AU)