Mice were orally given 1/20 LD50 of the pyrethroid insecticide cypermethrin twice a week for 20 months by gavage; it was found to induce sebaceous adenoma in the axillary region. Histological examination of liver tissues of mice treated with cypermethrin showed mild to severe degrees of congestion and haemorrhages from the various vasculatures in addition to some liver cell degeneration, necrosis, cell rupture and lymphocytic infiltrations. The histological renal abnormalities were shown as degenerations of the kidney tubules (cloudy swelling) with occlusion in the lumina of these affected tubules in addition to haemorrhages, vascular changes of glomerular as well as inter tubular congestion, narrowing and occlusion in the tubule lumina. In addition, large areas of deep brown hemosiderin pigments were seen. The results indicate that the effects of cypermethrin may be more severe than the previous toxicological evaluations suggested.
Cypermethrin, Pyrethroid, Insecticides, Histopathology, Liver, Kidney, Mice