Radioprotective effect of chitosan in sub-lethally X-ray irradiated mice.

The radioprotective effect of chitosan was studied in mice following whole-body X-ray irradiation. C3H/He mice were exposed to 7 Gy, and their survival rates were examined. The survival rates of chitosan-diet mice were about 20% higher than those of mice on a standard diet, and the rates dropped sharply to a plateau at day 10 after X-ray irradiation. The chitosan-diet mice had an increased weight ratio of spleen to body within the experimental period. The leukocyte, thrombocyte, and erythrocyte counts as well as the hematocrit and hemoglobin levels were recovered significantly and more rapidly in the chitosan-diet mice than the standard-diet mice at day 14 after irradiation. The scavenging abilities of chitosan were evaluated by the ESR spin-trapping method. These observations suggested that chitosan led to hematopoetic activation and leukocytogenesis in mice after sub-lethal dose irradiation, and that the biological response might be caused by radical trapping or scavenging.