Whole body X-ray irradiation to mice decreases ascorbic acid concentration in bone marrow: comparison between...

The change in the ascorbic acid concentration in the bone marrow after whole body X-ray irradiation was compared with that in the vitamin E concentration. The ascorbic acid concentration in the bone marrow significantly decreased by 30% 1 h after exposure to 3 Gy of X-rays, whereas the vitamin E concentration in the bone marrow was significantly decreased 5 h after exposure, when the level of ascorbic acid was less than 10% of that in the control. At 24 h after exposure, the ascorbic acid concentration in the bone marrow was significantly decreased by 80% after exposure to 0.5 Gy, whereas the vitamin E concentration was significantly decreased after exposure to 1 Gy or more. In the bone marrow, the decrease in the ascorbic acid concentration was accompanied by a marked increase in the concentration of dehydroascorbic acid, an oxidized form of ascorbic acid. X-ray irradiation did not decrease either the ascorbic acid or vitamin E concentration in the serum or intestine. These findings suggest that the bone marrow is more highly susceptible to oxidative damage by radiation and that ascorbic acid plays an important defense role against it. On Day 8 after irradiation, the decreases in the vitamin E and ascorbic acid concentrations in the bone marrow showed recovery after exposure to 3 Gy, but not after the exposure to 6 Gy.