Long-term effects of radioprotector WR-2721 on locomotor activity and body weight of mice following exposure to ionizing radiation.

The effects of 13 Gy gamma-radiation alone and in combination with 200 mg/kg of the radioprotector S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721) on locomotor activity and body weight were examined in CD2F1 mice over a 10-month period. The results confirmed that WR-2721 is an excellent radioprotector against lethality. All mice receiving 13 Gy without WR-2721 died in 5-7 days. For mice that received WR-2721 alone or WR-2721 + radiation, survival at 30 days was 100% and 70%, respectively. Body weights of mice receiving WR-2721 without radiation were comparable to control animals. Body weights of animals given WR-2721 + radiation fell on days 1-5 and then increased until day 11, but remained below control values throughout the experiment. Animals in the radiation-only group did not exhibit any significant reductions in behavior until day 2 post-irradiation. Mice administered WR-2721 alone showed significantly reduced locomotor activity levels on day 0 then completely recovered within 24 h and exhibited normal body weights. Animals given WR-2721 before irradiation showed greater reductions in locomotor activity on day 0 than either the WR-2721 or radiation-only groups and recovered to control level by day 3. Beginning on day 5, they showed significant reductions in activity. Mice pretreated with WR-2721 that survived a normally lethal dose of radiation showed a 20-40% reduction in locomotor performance that recovered in 2-5 months.