The effect of donor age on spontaneous and induced micronuclei.

The spontaneous micronucleus yield in lymphocyte cultures from healthy donors aged 0-82 years was estimated at 72 h and 96 h of culture. At both 72 and 96 h there was a positive correlation of micronucleus expression with increasing age (p less than 0.001), with an approximately 4-fold increase in micronuclei in cultures from 80-year-old donors when compared to cultures from newborn donors. Since there is some evidence that the effect of DNA-damaging agents may increase with age, lymphocytes from individuals of various ages were exposed to X-rays and mitomycin C and micronuclei were scored after 72 and 96 h of culture. Micronucleus formation after exposure to these agents was, however, decreased in cells from elderly individuals, most likely due to kinetic differences between the lymphocytes of old and young individuals.