An investigation of the age-dependency of chromosome abnormalities in human populations exposed to low-dose ionising radiation

Among various cytogenetic changes stable chromosome aberrations (SCHA) seem to be the most significant for ageing and carcinogenesis. Being nonlethal they can persist through cell divisions and accumulate in time. We studied the age response of SCHA (translocations and insertions) in normal and radi ation exposed human populations. Two cohorts of people at the age range of 3-72 years were studied: control (43 persons) and exposed to low doses of a ccidental irradiation due to Chernobyl accident and atomic bomb testing in Semipalatinsk (67 persons). FISH method was used for visualisation of chrom osome aberrations. Metaphases from cultured lymphocytes were hybridised wit h biotinilated whole chromosome specific DNA probes for 1, 4 and 12 chromos omes, and with pancentromeric probe labelled with digoxigenin. The frequenc y of SCHA in lymphocytes increased as a quadratic function of donor age in both populations studied, being higher in exposed cohort as compared with c ontrol one. No age dependence for dicentrics was observed. The frequency of SCHA is a reliable biomarker of ageing in humans. Quadratic model of their age-response gives reasons to suggest that their increase is due to lower level of DNA repair or/and the genomic instability in older people. The exp osure of people to low doses of ionising radiation accelerates the age-rela ted increase of SCHA frequency. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.