Susceptibility of mouse splenic cells to oxidative DNA damage by x-ray irradiation.
Susceptibility to oxidative stress by X-ray irradiation was examined in splenic cells of BDF1 mouse and fetal human lung fibroblasts, TIG-7. Survival rates of splenic cells irradiated with X-rays were lower than those of TIG-7 cells irradiated similarly. The content of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) immediately after X-ray irradiation in the DNA of splenic cells increased until 2 Gy irradiation, but remained constant above 2 Gy. The 8-oxodG contents rose in proportion to the dose of X-rays in TIG-7 cells. Although the survival rate of splenic cells exposed to 1 Gy irradiation decreased with time, the survival rate of TIG-7 cells remained unchanged. The 8-oxodG content in splenic cells irradiated with X-rays did not decrease even 48 h after irradiation, while that in TIG-7 cells decreased with time, and recovered to the pre-irradiation level after 48 h. A DNA ladder was observed in splenic cells 2 h after X-ray irradiation, but the ladder was not found in fibroblasts. Furthermore, caspase-3 activity increased after X-ray irradiation of splenic cells. These results indicate that splenic cells are sensitive to oxidative stress induced by X-ray irradiation and that splenic cells damaged by even low doses of X-rays are removed through apoptosis rather than by a repair pathway.
Tahara
Shoichi
S
Redox Regulation Research Group, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo 173-0015, Japan.
Kaneko
Takao
T
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D004247:DNA / Q000302:isolation & purification / Q000528:radiation effects; D004249:DNA Damage / Q000528:radiation effects*; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000378:metabolism; D005347:Fibroblasts / Q000528:radiation effects; D008297:Male; D051379:Mice; D009336:Necrosis; D010084:Oxidation-Reduction; D013154:Spleen / Q000166:cytology* / Q000378:metabolism; D014965:X-Rays
D000080242:8-Hydroxy-2'-Deoxyguanosine; D004247:DNA; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D003849:Deoxyguanosine