PROTECTION OF IRRADIATED MICE BY DIPYRIDAMOLE

Abstract

Dipyridamole (Persentin), a vasodilatory drug with antiplatelet activity, has been recently reported to inhibit lipid peroxidation and scavenge oxygen radicals. The radioprotective effects of dipyridamole were studied in ddy mice. When the mice were irradiated to 8.0 Gy, 30 days-lethality was reduced from 89 % (control group) to 56 % (0.5mg/mouse and 1.0 mg/mouse i, p. injection of dipyridamole), and to 33 % (2.0 mg/mouse and 4.0 mg/ mouse i, p. injection) . The dose required to kill 50 % of the dipyridamole-tested mice within 30 days (LD_50/30) was 7.56 Gy compared to 6.63 Gy for the control mice. The results suggested that dipyridamole has significant radioprotective effect, so we clinically studied on its radioprotective effects using white-cell counts and platelet counts of 12 patients with breast cancer. Dipyridamole (150 mg/day) was administered to 6 of 12 patients during radiation therapy. There was no statistically significant difference between these two groups. These results suggest the other factor than radioprotective effects on bone marrow.