Evaluation of caffeine as a radioprotector in whole-body irradiated male mice.

Caffeine is the main psychoactive ingredient of coffee, tea and even colas. This study investigated the radioprotection of caffeine in mice. Mice were irradiated with 6.5 Gy. A caffeinetreated group was administered 80 mg/kg-body weight by an i.p injection at 1 hour before irradiation. At 6 hours after irradiation, the animals were sacrificed for the study. Hormonal analysis was performed with radioimmunoassay on serum. The expression kinetics of the apoptotic genes after irradiation was evaluated with RT-PCR. The weight of body and organ and H and E-stained slides did not show differences between groups. The circulating testosterone significantly decreased in the irradiated group. The expression of Fas antigen, p21, p53, bax and bcl2 related to radiation- induced apoptosis was comparable to that of the caffeine-untreated group. Bax mRNA dramatically increased in the irradiated group, but not in the irradiated caffeine -treated group. The results indicate that caffeine protects an early apoptotic initiation after irradiation.