Objective   To study the combined toxicity effect on the reproducion induced by benzene-for maldehyde.

  Methods   The effect on DNA damage in the testicle cells after peritoneal injection of benzene(50, 200, 800 mg/kg), formaldehyde (0.3, 1.2, 4.8 mg/kg)and benzene-formaldehydeat were measured using the single cell gel electrophoresis technique(comet assay)tests respectively.

  Results   Within tested doses, the mumber of comet cells in the testicle cells was significantly increased as benzene of formaldehyde exposue dose increased(P < 0.01).The length of DNA migration was significantly increased as benzene increased(P < 0.01)but was sho rtened as formaldehyde increased, especially high formaldehyde dose(P < 0.01).Among combined exposure doses, the length of DNA migration was uniformly increased as benzene increased(P < 0.01)but was shortened as formaldehyde increased(P < 0.01).There was a addition effect between benzene and formaldehyde with factorial analysis(P < 0.01).

  Conclusion   Benzene and for maldehyde could promote the response of DNA damage of testicular cells each other.