DEMONSTRATION OF CHLOROBENZENE-INDUCED DNA-DAMAGE IN MOUSE LYMPHOCYTES USING THE SINGLE-CELL GEL-ELECTROPHORESIS ASSAY

The DNA damaging effect of chlorobenzene was investigated in periphera l lymphocytes and bone marrow cells from C57BL/6 female mice using a g el electrophoresis assay for DNA from single cells ('the single cell g el electrophoresis assay') under alkaline conditions. The effect of ch lorobenzene was studied both after single and repeated intraperitoneal injections of 750 mg/kg body weight. The cytostatic agent cyclophosph amide (150 mg/kg, i.p.) was used as a reference substance, and vehicle -treated mice as controls. DNA damage was recorded 16 h after the (las t) injection, using an automated computerized image analysis system sp ecifically designed for the single cell gel electrophoresis assay. The re was evidence of chlorobenzene-induced DNA damage after 3 days of re peated exposure in peripheral lymphocytes, but no indications of such an effect in bone marrow cells. Cyclophosphamide induced significant d amage to DNA both in bone marrow cells and lymphocytes, the effect bei ng most pronounced in the latter cells. It is concluded that high-dose exposure to chlorobenzene is associated with genotoxicity to peripher al lymphocytes. However, this solvent is apparently not a major hazard to bone marrow cells, even after repeated high-dose exposure.