Simultaneous Action of Cypermethrin and Two Environmental Pollutant Metals, Cadmium and Lead, on Bone Marrow Cell Chromosomes of Rats in Subchronic Administration☆

Abstract The aim of the present study was to investigate the possible genotoxic effects, exerted by the pyrethroid cypermethrin and by either of the metals cadmium and lead alone or in combination, on bone marrow cell chromosomes in a subchronic experiment. Outbred male Wistar rats were treated per os for 4 weeks in a five-time per week schedule with 5.54, 11.08, or 22.16 mg/kg cypermethrin (1/100, 1/50, 1/25 LD 50 ) alone, or in combination of 1/100 and 1/50 LD 50 cypermethrin with 2.0 mg/kg cadmium chloride or 10 mg/kg lead acetate. On the day following the last treatment, the animals were sacrificed and bone marrow from the femur was prepared. Twenty metaphases from 10 animals per group were evaluated. The evaluation comprised the frequency of aberrant cells, the numerical and structural aberrations, and the alterations in relative organ weights. In the dosage used, cypermethrin and cadmium alone caused no significant increase in the chromosomal aberrations, and lead acetate caused an increase of the numerical aberrations only. Combination of cypermethrin and cadmium also failed to induce significant chromosomal effects. The cypermethrin+lead combination, however, induced a significant increase of structural chromosomal abberations, predominantly of all acentric fragments. This lead to the conclusion that the simultaneous administration of lead and cypermethrin results in an enhanced genotoxic effect.