title: Reduction of radiation-induced chromosome aberration and apoptosis by dithiothreitol.
abstract: We have examined in vitro and in vivo radioprotective effects of a well-known thiol-containing compound, dithiothreitol (DTT). The treatment of both 0.5 and 1 mM of DTT significantly increased clonogenic survival of gamma-ray irradiated Chinese hamster (V79-4) cells. In order to investigate the possible radioprotective mechanism of DTT, we measured gamma-ray induced chromosome aberration by micronucleus assay. In the presence of 0.5 mM or 1 mM DTT, the frequencies of micronuclei were greatly reduced in all dose range examined (1.5-8 Gy). Slightly higher reduction in micronucleus formation was observed in 1 mM DTT-treated cells than in 0.5 mM DTT-treated cells. In addition, incubation with both 0.5 and 1 mM of DTT prior to gamma-ray irradiation reduced nucleosomal DNA fragmentation at about same extent, this result suggests that treatment of DTT at concentrations of 0.5 and 1 mM reduced radiation-induced apoptosis. In vivo experiments, we also observed that DTT treatment reduced the incidence of apoptotic cells in mouse small intestine crypts. In irradiated control group 4.4 +/- 0.5 apoptotic cells per crypt were observed. In DTT-administered and irradiated mice, only 2.1 +/- 0.4 apoptotic cells per crypt was observed. In vitro and in vivo data obtained in this study showed that DTT reduced radiation-induced damages and it seems that the possible radioprotective mechanisms of action of DTT are prevention of chromosome aberration.
authors.affiliation: Department of Biochemistry, College of Dentistry, Kyung Hee University, Seoul, Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Kim
authors.forename: E J
authors.initials: EJ
authors.lastname: Lee
authors.forename: J W
authors.initials: JW
authors.lastname: Hyun
authors.forename: S H
authors.initials: SH
authors.lastname: Kim
authors.forename: W
authors.initials: W
authors.lastname: Mar
authors.forename: J K
authors.initials: JK
authors.lastname: Kim
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D002869:Chromosome Aberrations / Q000502:physiology*; D006224:Cricetinae; D053938:DNA Fragmentation; D004229:Dithiothreitol / Q000494:pharmacology*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005720:Gamma Rays; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000187:drug effects; D015162:Micronucleus Tests; D011837:Radiation-Protective Agents / Q000494:pharmacology*
chemical_list: D011837:Radiation-Protective Agents; D004229:Dithiothreitol