Rejoining kinetics of bleomycin-induced DNA single-strand breaks in agarose-bound human blood cells.
The rejoining kinetics of individual DNA single-strand breaks (SSBs) are difficult to measure, in biomonitoring studies, because SSB rejoining is rapid and hard to control. We have detected early (0, 1, 2, 5, 10 and 30 min) events in SSB rejoining in human leukocytes, with the alkaline comet assay, at a low concentration of bleomycin (BLM; 0.5 μg/ml). Background Tail DNA% (percentage of DNA that remained in the comet tail) of the subjects was 1.23% (25th-75th percentile: 0.72-1.64). BLM treatment increased this to 62.4% (25th-75th percentile: 57.8-70.4) at t=0, decreasing to the background level by 30 min. Analysis of 45 subjects showed that the fastest return to the background level occurred in 5 min, whereas the slowest return took approximately 30 min. The early rejoining kinetics of SSBs may show multiple patterns, varying among individuals.
Department of Social and Environmental Medicine, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka Osaka 565-0871, Japan. Electronic address: lu@envi.med.osaka-u.ac.jp.
Yuquan
Y
Lu
Kyoto Medical Science Laboratory, Furukawa-cho 328, Hazukashi Fushimi-ku, Kyoto 812, Japan.
Ryoichi
R
Matsuse
Department of Social and Environmental Medicine, Osaka University Graduate School of Medicine, 2-2 Yamada-Oka Osaka 565-0871, Japan.
Tomotaka
T
Sobue
D000328:Adult; D000903:Antibiotics, Antineoplastic / Q000494:pharmacology*; D001761:Bleomycin / Q000494:pharmacology*; D018914:Cells, Immobilized; D020552:Comet Assay; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D053904:DNA Breaks, Single-Stranded; D059766:DNA End-Joining Repair; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012685:Sepharose / Q000737:chemistry
D000903:Antibiotics, Antineoplastic; D001761:Bleomycin; D004247:DNA; D012685:Sepharose
Agarose-bound cell culture; Batch processing; Bleomycin; Comet assay; DNA repair