p53 accumulation in the organs of low-dose X-ray-irradiated mice

In order to search for the direct evidence of cellular response to low-dose radiation, we investigated wild-type p53 protein accumulation in several organs of mice after exposure to low doses of X-rays. Significant p53 accumulation within 24 h was observed in the mouse adrenal glands and pancreas after X-ray irradiation at 25 cGy and 50 cGy, but not at 100 cGy. In addition, differential p53 accumulation was also observed in the hypophysis, thymus, skin, lung, bone marrow and liver at different doses. In contrast, we observed no accumulation of p53 protein in the spleen, testis or kidney at any dose used in this experiment. The p53 accumulation induced by low-dose X-rays in mice was organ-specific. It is suggested that cell type and interactions with other signal transduction pathways of the hormone system, immune system and/or nervous system may contribute to the variable induction of p53 by low-dose X-ray irradiation. The association of organ-specific p53 response with radiosensitivity and cancer incidence by radiation in each organ was discussed.