Styrene and vinyltoluene induce micronuclei in mouse bone marrow.

Male C57BL/6 mice were treated i.p. with a single dose of styrene (250, 500, 1000 or 1500 mg/kg b.wt; 4 animals/group), vinyltoluene (100, 200, 300 or 500 mg/kg b.wt; 4-5 animals/group) or olive oil (controls, 13 animals). A significant increase in micronucleated polychromatic erythrocytes was observed at 250 and 1000 mg/kg b.wt of styrene and at 200, 300 and 500 mg/kg b.wt of vinyltoluene. 1000 and 1500 mg/kg b.wt of styrene and 100, 200 and 300 mg/kg b.wt of vinyltoluene significantly decreased the ratio of polychromatic to normochromatic erythrocytes. There was no increase in normochromatic cells with micronuclei.