Abstract:
[Objective] To explore genotoxicity of formaldehyde and benzene joint inhalation on bone-marrow cells of male mice, and to provide a scientific basis about evaluating the safety exposure to formaldehyde and benzene.
[Methods] Sixty healthy and clean Kunming inbred strain male mice were randomly divided into 10 groups with 6 mice in each group. The negative control group were exposed to clean air. The 3 formaldehyde treatment groups were exposed to formaldehyde at dosage of 1.0 mg/m3 (the low dose group), 3.0 mg/m3 (the moderate dose group), or 5.0 mg/m3 (the high dose group). The benzene treatment groups were exposed to benzene at dosage of 500.0 mg/m3 (the low dose group), 1 500.0 mg/m3 (the moderate dose group), or 2 500.0 mg/m3 (the high dose group). The joint treatment groups of formaldehyde and benzene were exposed to those at dosage of 0.5+250.0 mg/m3 (formaldehyde+benzene), 1.5+750.0 mg/m3, and 2.5+1 250.0 mg/m3 respectively. The treatments were conducted by static inhaling for two consecutive weeks, two hours a day, then the mice were killed on 15th day. The genotoxicity of formaldehyde and benzene was tested by micronucleus assay and single cell gel electrophoresis (comet assay).
[Results] Compared with the negative control group, micronucleus rate, tail DNA% and tail moment in each dose group of formaldehyde or benzene exposure groups and joint exposure groups were much higher (P < 0.05). Compared with single exposure groups, the micronucleus rate of each dose group of the joint exposure groups was much higher (P < 0.05), the tail DNA% and tail moment in the low dose group and the moderate dose group of the joint exposure groups were much higher (P < 0.05). The tail DNA% and tail moment in the high dose group of the joint exposure groups were much higher than single formaldehyde high dose group (P < 0.05), but not higher than single benzene high dose group.
[Conclusion] The genetoxic effect of combined exposure to formaldehyde and benzene on the bone-marrow cells of the male mice was more severe than that of the single exposure, which may be caused by the synergistic toxic effect.
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