DNA damage susceptibility and repair in correlation to calendric age and longevity

In two mouse strains, SAM P (senescence acceleration prone) and SAM R (sene scence acceleration resistant), of different longevities, with a ratio of P /R = 1:2), the DNA status in the course of aging has been investigated usin g the DNA Alkaline Filter Elution (AFE) technique. Six different organs (br ain, liver; heart, lung, intestine, and muscle) have been used in each of t he four animals of a given age. Earlier it had been shown, that DNA is dama ged the more the higher the age of the animal. DNA damage susceptibility, m easured after exposure of organ pieces to nitroquinoline-N-oxide (NQO), is also significantly increased at higher ages, while repair, measured of NQO damaged tissue after 3 h incubation in full medium is significantly reduced . In the strain with shorter longevity the damage increments and the repair deficiencies are drastically deviating from those with higher longevity. T hese findings of strong coupling of the DNA status to aging as well as long evity suggest causative relations. (C) 2000 Elsevier Science Ireland Ltd. A ll rights reserved.