Radio-adaptive response: characterization of a cytogenetic repair induced by low-level ionizing radiation in cultured Chinese hamster cells.
Pretreatment with low doses of beta-rays from incorporated tritiated thymidine ([3H]dThd) or of Co-60 gamma-rays (1 or 5 cGy) rendered actively growing Chinese hamster V79 cells more resistant to the induction of micronuclei or sister-chromatid exchanges (SCEs) by a subsequent high dose of gamma-rays (1 Gy). This adaptive response to ionizing radiation (radio-adaptive response) can be induced by an optimal range of low doses of 3H beta-rays, but not by much lower or higher adapting doses. Full expression of the adaptive response induced by the exposure to low doses of 60Co gamma-rays occurred 4 h after the adapting dose. The cells pre-exposed to low doses of gamma-rays showed cross-resistance to challenge doses of gamma-rays themselves and also of mitomycin C (MMC) and near ultraviolet light (UV-B, 313 nm), but not to those of ethyl methanesulfonate (EMS) or cis-platinum (II) diammine dichloride (cisplatin) for SCE induction. These results suggest that the radio-adaptive response mechanistically couples to the repair network which copes with chromatin lesions induced by MMC and UV-B.
Ikushima
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Research Reactor Institute, Kyoto University, Osaka, Japan.
D000818:Animals; D001610:Beta Particles; D002460:Cell Line; D002945:Cisplatin / Q000494:pharmacology; D006224:Cricetinae; D003412:Cricetulus; D004260:DNA Repair / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005020:Ethyl Methanesulfonate / Q000494:pharmacology; D005720:Gamma Rays; D066298:In Vitro Techniques; D015162:Micronucleus Tests; D016685:Mitomycin; D008937:Mitomycins / Q000494:pharmacology; D012854:Sister Chromatid Exchange / Q000528:radiation effects; D013997:Time Factors; D014316:Tritium; D014466:Ultraviolet Rays
D008937:Mitomycins; D014316:Tritium; D016685:Mitomycin; D005020:Ethyl Methanesulfonate; D002945:Cisplatin