Amifostine protects blood vessels from the effects of ionizing radiation.

Amifostine (WR-2721) is a well-known radioprotective drug, selective for normal cells. The purpose of the present study was to define whether amifostine protects the vascular network from the effects of X-rays. We used the in vivo system of chicken embryo chorioallantoic membrane (CAM) as a model of angiogenesis. Amifostine reversed the early X-rays- induced decrease in the number of CAM blood vessels and reversed the early radiation-induced apoptosis of CAM cells. It also inhibited the increase in tyrosine nitration of actin and a-tubulin, which was observed 6 hours after CAM irradiation, when there was a significant decrease in non-protein SH groups. Furthermore, C6 rat glioma cells were inoculated on CAM and tumor growth, as well as tumor-induced angiogenesis, was estimated on haematoxylin-eosin-stained paraffin sections. Amifostine inhibited the post irradiation increase of C6 tumor-induced angiogenesis. These data suggest that amifostine protects CAM cells and blood vessels from the effects of X-rays, through mechanisms that do not depend solely on its free radical scavenging properties.