[Single-strand DNA breaks and chromosome aberrations in the hepatocytes of mice of different ages]

The same damages were found to occur in hepatocyte DNA from old mice of different strains by means of sedimentation in alkaline sucrose concentration gradient. At the same time, the number of hepatocytes with aberrant chromosomes is strongly different in these strains. From these data an assumption is made that some other damages being accumulated with aging are responsible for chromosome aberrations except for single-strand DNA breaks. The number of single-strand breaks registered in hepatocyte DNA of the old animals under gamma-irradiation is two-three times more than that of the young animals, though the rates of repair of the induced single-strand breaks in DNA are the same for mice of different age and strains.