Modulation of cyclophosphamide mutagenicity by vitamin C in the in vivo rodent micronucleus assay.

The modulatory effect of vitamin C (Vit C) on the mutagenic effect of the antineoplastic drug cyclophosphamide (CP) was assessed in the in vivo micronucleus test in Swiss mice. Simultaneous oral administration of Vit C with i.p. administration of CP was found to decrease the frequency of micronucleated polychromatic erythrocytes elevated by CP. Vit C exhibited a significant antimutagenic effect over a wide dose range (1.56-200 mg/kg). The dose-response relationship was highly significant. These results demonstrated the ability of the in vivo micronucleus test to detect in vivo modulation of CP mutagenicity by Vit C. Our earlier results and those from other laboratories also indicate that this model system is suitable for primary in vivo screening of modulation of mutagenesis.