ascorbic-acid and diepoxybutane

To validate the alkaline single cell gel (SCG) assay as a tool for the detection of DNA damage in human leukocytes, we investigated the in vitro activity of 18 chemicals. Thirteen of these chemicals (pyrene (PY), benzo(a)pyrene (BaP), cyclophosphamide (CP), 4-nitroquinoline-1-oxide (4NQO), bleomycin (BLM), methylmercury chloride (MMC), mitomycin C (MTC), hydrogen peroxide (HP), diepoxybutane (DEB), glutaraldehyde (GA), formaldehyde (FA), griseofulvin (GF), sodium azide (NA)) are genotoxic in at least one cell system, while five compounds (ascorbic acid (AA), glucose (GL), D-mannitol (MAN), O-vanillin (VAN), chlorophyllin (CHL)) are classified as non-genotoxic. In this in vitro SCG assay, PY, BaP and CP were positive with exogeneous metabolic activation (rat S9 mix) while 4NQO, BLM, MMC, MTC, hydrogen peroxide, and diepoxbutane were positive in the absence of metabolic activation. CHL and VAN were unexpectedly found to induce a dose-dependent increase in DNA migration. AA, GL, and MAN were negative in a non-toxic range of doses. GF gave equivocal results, while FA and GA increased DNA migration at low doses and decreased DNA migration at higher doses. This behaviour is consistent with the known DNA damaging and crosslinking properties of these compounds. These data support the sensitivity and specificity of this assay for identifying genotoxic agents.

Topics: 4-Nitroquinoline-1-oxide; Adult; Animals; Ascorbic Acid; Benzaldehydes; Benzo(a)pyrene; Biotransformation; Bleomycin; Chlorophyllides; Cyclophosphamide; DNA Damage; Epoxy Compounds; Female; Formaldehyde; Glucose; Glutaral; Griseofulvin; Humans; Hydrogen Peroxide; Hydrogen-Ion Concentration; Leukocytes; Mannitol; Methylmercury Compounds; Microsomes, Liver; Mitomycin; Mutagenicity Tests; Pyrenes; Rats; Reproducibility of Results; Sodium Azide

Peripheral blood lymphocytes from eight Fanconi anemia (FA) patients, 14 FA heterozygotes, and nine normal subjects have been tested for their susceptibility to chromosomal breakage induction by diepoxybutane (DEB) and by two peroxides. In addition, the effect of five antioxidants was investigated in standard cultures and in cultures stressed either with DEB or with butylhydroperoxide (BHP) or with hydrogen peroxide (H2O2). DEB, BHP, and H2O2 dramatically increased the chromosomal breakage levels in homozygous and heterozygous FA cells. A partial correction of chromosomal instability was obtained by treating the patients' lymphocytes with antioxidants. A "protective" effect was also noted in the DEB or peroxide-stressed lymphocytes of patients and heterozygotes, grown in the presence of antioxidants.

Topics: Anemia, Aplastic; Antioxidants; Ascorbic Acid; Cells, Cultured; Chromosome Aberrations; Cross-Linking Reagents; Cysteine; Epoxy Compounds; Ethers, Cyclic; Fanconi Anemia; Glutathione; Heterozygote; Homozygote; Humans; Hydrogen Peroxide; Lymphocytes; Mercaptoethanol; Peroxides; Tiopronin

Topics: Anemia, Aplastic; Antioxidants; Ascorbic Acid; Chromosome Aberrations; Cysteine; Epoxy Compounds; Ethers, Cyclic; Fanconi Anemia; Humans; Hydrogen Peroxide; Mercaptoethanol; Mutagens; Oxygen Consumption; Peroxides; tert-Butylhydroperoxide