BACKGROUND: Different stressors affect the genome integrity, but the mechanisms of such action are underexplored. MATERIALS AND METHODS: Bone marrow and testicular cells of CBA and CD-1 mouse males were used to estimate their genome integrity after stressor action by the comet assay. RESULTS: It is shown here that restraint and 2,5-dimethylpyrazine both increase damaged cell frequency in bone marrow as well as in testes of mouse males. For the first time the effect of immobilization and 2,5-dimethylpyrazine in testicular cells is demonstrated using the comet assay. Both stressors have similar effects in cells of both tissues analyzed. CONCLUSION: Mechanisms of the effects and possible role in microevolution are under discussion.