Effect of amifostine (Ethyol) on the development of extraembryonic blood vessels in chick embryos.

Abstract

Systemic and local side effects can limit radio- as well as chemotherapy in patients suffering from neoplastic diseases. One possibility to reduce the therapy-dependent side effects is to attenuate radical induced alterations of normal healthy tissue by application of antioxidants. Preclinical and clinical studies demonstrated the ability of amifostine to protect normal, but not neoplastic, tissues from cytotoxic effects of chemotherapy or irradiation. The purpose of the present study was to establish whether amifostine (Ethyol) can affect microvessel density in vivo. For this study fertilized crossbred "White-Plymouth-Rocks x Sussex" eggs were used. After 48 hours of incubation 0.05 ml solution containing 25.7 micrograms (approximately 120 microM) amifostine were injected next to the germ disc. Taking into account the mean surface area of the are vasculosa and the embryo, this corresponds to a dose of 26 micrograms/cm2. As controls, the area vasculosa of eggs treated with 0.05 ml NaCl 0.9% were used. Twenty-four and 48 hours after injection of amifostine or NaCl photographs and video microscopic pictures from treated areas and controls were taken and evaluated for vascular density. Results of vascular density are given as vascular intersections per mm2 (VIS/mm2). There was a significant (p < 0.001) difference in vascular density with a mean microvessel count of 30.40 (+/- 12.84 SD) VIS/mm2 in the NaCl control and 53.69 (+/- 24.56 SD) VIS/mm2 in the amifostine-treated area vasculosa. The results show that amifostine induced an increase in vascular density in the rapidly proliferating area vasculosa of the early chick embryo.