The degree of radiation protection from Nicaraven after whole-body irradiation was investigated in C3H mice. Nicaraven is a free radical scavenging agent, which was shown to improve brain edema and blood flow. Nicaraven was injected intraperitoneally in mice before and/or after whole-body irradiation with 640cGy or 740cGy using Toshiba Lineac LMR-4C (4MV, 6.45×10-2C/kg/min). The 30 day survival ratio was improved significantly by Nicaraven (P≤0.02). Endogenous spleen colony formation was investigated after 640cGy. The agent was injected before (pre), after (post) or before and after irradiation (pre-post), and compared with the untreated group (control). Nine days after irradiation, the mean colony formation was 2.00 (pre), 3.09 (post), 4.31 (pre-post) and 1.47 (control). The differences between pre and post (p≤0.01), between pre-post and control (p≤0.01) and between post and control (p≤0.05) were significant. Nicaraven induced recovery of leukocyte and lymphocyte counts after irradiation, but not that of erythrocytes. The effect of the agent on mice liver mitochondrial lipid peroxidation was also investigated. The lag time was not shortened, but reduction of the TBA value was observed. Nicaraven was not only recognized as a radioprotector, but its ability to promote recovery from the damage caused by irradiation was also suggested.
