Influence of Environmental Oxygen Concentration on Enlargement and Vascular Density of the area Vasculosa in Chick Embryos

Abstract

Hypoxia is known to induce an upregulation of different genes (Shweiki et al. 1992, Gldberg and Schneider 1994). Among these genes are different ones encoding for growth fctors. Thus hypoxia can lead to a consecutive proliferation of e.g. endothelial cells. As sown by Höper and Jahn (1995) in the Area vasculosa of the early chick embryo hypoxia nt only induces an increase in vascular density but also an enlargement of the vascularized aea. Hyperoxia, on the other hand, is followed by a smaller vascularized area but aso an increased vascular density. This indicates that vasculogenesis, angiogenesis and gowth of the vascularized area are influenced by oxygen in different ways.