Histopathological efficiency of amifostine in radiation-induced heart disease in rats

Abstract

OBJECTIVE: Amifositine is a phosphorylated thiol that holds its radioprotective actions by several indirect mechanisms. The purpose of this study was to evaluate histopathologically whether amifositine administration prior to irradiation would have a long-term protective effect on heart tissue in an experimental rat model. METHODS: Single dose of 18 Gy radiation and sham radiation exposure were used in related groups. A dose of 200 mg/kg of amifostine was injected intraperitoneally 30 min prior to radiation exposure. Analyses were performed 6 months after irradiation. RESULTS: Vascular damage and vasculitis were significantly decreased in amifositine treatment group. At the same time, significant thickening of the medial layer was accompanied by vascular damage in irradiated groups. The number and severity of myocyte necrosis were diminished with amifostine. Nevertheless, it could not prevent epicardial and myocardial fibrosis. Severe myocardial fibrosis was observed prominently in three regions, particularly on the apex, tips of papillary muscles and in sites adjacent to the atrioventricular valves. The anti-inflammatory effect of amifostine was not seen. CONCLUSION: The development of vascular damage and vasculitis were prevented by the use of amifostine. There was a correlation between vascular damage and fibrosis development. According to histopathological results, amifostine could be used as a protective agent against the side effects of radiotherapy (Tab. 4, Fig. 2, Ref. 22).