Mitochondrial DNA deletions in tissues of mice after ionizing radiation exposure

Purpose: The objective of the study was to estimate the presence of large mtDNA deletions in brain and spleen tissues of mice four months after exposure to 2 and 5Gy.Materials and methods: The male BALB/c mice underwent X-ray total-body acute radiation. Four months after irradiation, the mice were decapitated, and the samples of spleen and brain tissues were examined. A long-distance PCR was used to detect mtDNA deletions and their levels in samples of brain and spleen tissues.Results: Four months after irradiation the levels of mtDNA deletions in the brain and spleen tissues were higher in animals exposed to 5Gy than in animals at an irradiation dose of 2Gy and in control mice. The levels of deletions in the mice brain tissues were higher 4 months than 1 month after X-ray exposure to both doses (2 and 5Gy). In spleen tissues, a higher level of deletions was observed only at an irradiation dose of 5Gy.Conclusions: Our data have shown that ionizing radiation induces an increase of mtDNA copies with deletions in tissues of mice four months after the post-irradiation period. The level of deletions depends on the animal age, type of tissue, irradiation dose and length of the post-irradiation period.