DNA strand breakage, cytotoxicity and mutagenicity of hydrogen peroxide treatment at 4 degrees C and 37 degrees C in L5178Y sublines.
Cells from the L5178Y murine lymphoma subline LY-R are twofold more resistant to killing by ionizing radiation than the subline LY-S. In contrast, LY-R cells are more sensitive to killing by hydrogen peroxide. Cells of the two sublines in logarithmic growth phase were treated with hydrogen peroxide in phosphate-buffered saline for 1 h at 4 degrees C or 37 degrees C. From the comparison of D(o) values it followed that at 37 degrees C LY-R were 3.6 times more sensitive to the killing effect of H2O2 than LY-S cells; at 4 degrees C they were 11 times more sensitive. Treatment with hydrogen peroxide at 4 degrees C gave a considerable sparing effect, which was substantially greater for the LY-S subline; for LY-S cells D(o) was 5.7 times lower at 37 degrees C than at 4 degrees C, for LY-R cells only 1.9 times. The mutation frequency (HGPRT) in LY-R cells was increased in proportion to H2O2 concentration and was the same at both treatment temperatures. In contrast, mutation frequencies initially increased, then decreased with increasing H2O2 concentration in LY-S cells treated at 4 or 37 degrees C. The concentration at which the decline was initiated was higher at 4 than at 37 degrees C. DNA damage after H2O2 treatment (both temperatures, 5 min) was estimated from the 'comet' assay (single-cell gel electrophoresis). The initial damage, but not the residual damage, differed significantly in LY sublines. A period of slower repair (between 3 and 10 min) was found in LY-R cells.
Kruszewski
M
M
Department of Radiobiology and Health Protection, Institute of Nuclear Chemistry and Technology, Warsaw, Poland.
Green
M H
MH
Lowe
J E
JE
Szumiel
I
I
D000818:Animals; D002374:Catalase / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D004249:DNA Damage; D004260:DNA Repair; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance; D004361:Drug Tolerance / Q000235:genetics; D004587:Electrophoresis, Agar Gel / Q000379:methods; D006861:Hydrogen Peroxide / Q000633:toxicity*; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D007940:Leukemia L5178; D051379:Mice; D016296:Mutagenesis; D009152:Mutagenicity Tests; D013696:Temperature; D013866:Thioguanine / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects
D006861:Hydrogen Peroxide; D002374:Catalase; D007041:Hypoxanthine Phosphoribosyltransferase; D013866:Thioguanine