Protection against local irradiation injury to the skin by locally and systemically applied drugs

The radioprotective effects of systemically and topically administered cysteamine and WR-2721 were studied in irradiated mouse skin. Topically applied cysteamine showed significant protection only with moderate doses of irradiation. Topically applied WR-2721 had no protective effect at any dose. Systemically administered cysteamine yielded a dose reduction factor (DRF) of 1.7 for acute skin reactions and WR-2721 yielded a DRF of 2.0. Both agents showed a DRF of 1.5 for late tissue changes when administered systemically. The DRF for late tissue changes following local irradiation may be a more meaningful parameter of protective action than the DRF for acute whole-body lethality.