Benzene-induced genotoxicity in mice in vivo detected by the alkaline comet assay: reduction by CYP2E1 inhibition

TY - JOUR

T1 - Benzene-induced genotoxicity in mice in vivo detected by the alkaline comet assay

T2 - reduction by CYP2E1 inhibition

AU - Tuo, J

AU - Loft, S

AU - Thomsen, M S

AU - Poulsen, H E

PY - 1996/7/5

Y1 - 1996/7/5

N2 - The myelotoxic and genotoxic effects of benzene have been related to oxidative DNA damage after metabolism by CYP2E1. Single cell gel electrophoresis (alkaline comet assay) detects DNA damage and may thus be a convenient method for the study of benzene genotoxicity. Benzene exposure to NMRI mice as a single oral gavage at 40, 200 or 450 mg/kg resulted in dose-related DNA damage indicated by an increased comet tail length of peripheral blood lymphocytes and bone marrow nucleated cells sampled 6 h after exposure. After a dose of 40 mg/kg, there was a 1.6-fold increase of 'tail length' in bone marrow nucleated cells in comparison with the control (p < 0.01). There was no significant increase in DNA damage in peripheral blood lymphocytes in the same animals. At 200 mg/kg, the tail length was 4.8-fold and 4.0-fold increased in the two cell types, respectively (p < 0.01). At 450 mg/kg, the tail length was further increased to 5.4-fold and 6.6-fold of the control values, respectively (p < 0.01). Pretreatment with propylene glycol (5 microliters/g b.wt., twice with a 60-min interval), a selective CYP2E1 inhibitor, reduced the increase in the tail length by about half at all doses in both cell types (p < 0.01). By comparing our data with those from genotoxicity studies on benzene using other methods, we conclude that the 'alkaline comet assay' is a sensitive method to detect DNA damage induced by benzene. We also infer that CYP2E1 contributes, at least partly, to the formation of the 'comet'-inducing metabolites in the chosen cell types.

AB - The myelotoxic and genotoxic effects of benzene have been related to oxidative DNA damage after metabolism by CYP2E1. Single cell gel electrophoresis (alkaline comet assay) detects DNA damage and may thus be a convenient method for the study of benzene genotoxicity. Benzene exposure to NMRI mice as a single oral gavage at 40, 200 or 450 mg/kg resulted in dose-related DNA damage indicated by an increased comet tail length of peripheral blood lymphocytes and bone marrow nucleated cells sampled 6 h after exposure. After a dose of 40 mg/kg, there was a 1.6-fold increase of 'tail length' in bone marrow nucleated cells in comparison with the control (p < 0.01). There was no significant increase in DNA damage in peripheral blood lymphocytes in the same animals. At 200 mg/kg, the tail length was 4.8-fold and 4.0-fold increased in the two cell types, respectively (p < 0.01). At 450 mg/kg, the tail length was further increased to 5.4-fold and 6.6-fold of the control values, respectively (p < 0.01). Pretreatment with propylene glycol (5 microliters/g b.wt., twice with a 60-min interval), a selective CYP2E1 inhibitor, reduced the increase in the tail length by about half at all doses in both cell types (p < 0.01). By comparing our data with those from genotoxicity studies on benzene using other methods, we conclude that the 'alkaline comet assay' is a sensitive method to detect DNA damage induced by benzene. We also infer that CYP2E1 contributes, at least partly, to the formation of the 'comet'-inducing metabolites in the chosen cell types.

KW - Animals

KW - Benzene

KW - Cytochrome P-450 CYP2E1

KW - Cytochrome P-450 Enzyme Inhibitors

KW - Cytochrome P-450 Enzyme System

KW - DNA

KW - DNA Damage

KW - Male

KW - Mice

KW - Oxidoreductases, N-Demethylating

KW - Propylene Glycol

KW - Propylene Glycols

M3 - Journal article

C2 - 8692227

SN - 0027-5107

VL - 368

SP - 213

EP - 219

JO - Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis

JF - Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis

IS - 3-4

ER -