DNA double-strand breaks in mouse kidney cells with age

A Biojector device fitted with a CO2 cartridge was used to prepare single cellsuspensions from kidneys of 12-month-(middle-aged) and 24-month-old (old) C57Bl/6mice. Microgel electrophoresis of DNA fromthese cells revealed a modest but significant7.3% increase (P = 0.04) in DNA double-strand breaks in old mice. This increase is equivalent to the DNA damage induced by 0.1 Gray of X-rays (5 double-strand breaks) in kidney cells of 10-month-old mice, as determined by a standard calibration curve. Greater DNA damage with aging was also positively correlated with higher levels of pathology in the kidneys.