The carcinogenicity of discontinuous inhaled benzene exposures in CD-1 and C57Bl/6 mice.

摘要: Groups of male C57Bl and CD-1 mice were exposed to benzene via inhalation using two different exposure protocols. One protocol consisted repetitive week-long exposures 300 ppm (6 h/d×5 d/wk) interrupted by 2 weeks non-exposure. The pattern (1 week followed non-exposure) was continued until the death last animal. second 1200 for 10 weeks. Exposures then terminated animals allowed live out their lives. For each protocol, appropriate age-matched control received comparable filtered, conditioned air. discontinuous patterns mimic often encountered in workplace and, addition, prolong survival so as maximize potential tumorigenic responses. Both protocols markedly hematotoxic both mouse strains measured peripheral blood counts. responded intermittent with elevated incidences malignant tumors. Particularly noteworthy a 35% incidence zymbal gland tumors mice. In contrast, only CD−1 delivered over tumor incidences. A 46% lung adenoma particularly striking these Neither induced leukemia/lymphoma either strain. These studies demonstrate that are lifetime benzene, even if at lower concentration an pattern, is more than short-term benzene.