No Increase of Large-scale Mitochondrial DNA Deletions in Peripheral Blood Cells in Residents of Kazakhstan around Semipalatinsk Nuclear Test Site

Abstract

The study was set out to elucidate whether there are detectable differences in the molecular features of mitochondrial DNA (mtDNA) from peripheral blood lymphocytes (PBLs) between individuals possibly exposed to radiation due to fallouts from Semipalatinsk Nuclear Test Site and those who lived in non-contaminated area in Kazakhstan. Subjects were residents of three villages in Kazakhstan considered to be affected with radionuclides in the past. Control individuals were from one non-contaminated settlement in Kazakhstan and age-matched Japanese volunteers. Two parameters, the relative mtDNA content and abundance of large-scale deletions (LSDs) in mtDNA were estimated by real-time PCR and a PCR adjusted to sensitively reveal the LSDs, respectively. Relative content of mtDNA as well as the abundance of LSDs were found to differ non-significantly both in Kazakhstan radiation exposed, control Kazakhstan and Japanese individuals. LSD scores displayed no regular or statistically significant association with the mtDNA content in any group tested. Lack of correlation between the number of LSDs and mtDNA level occurred irrespectively the radiation history of a blood donor or individual's age. We conclude that the molecular parameters of PBL mtDNA measured in this work are unlikely to be informative as a bioindicator of radiation exposure.