Effects of oral exposure of synthetic pyrethroid, cypermethrin on the behavior of F1-progeny in mice.

Cyermethrin, a type II synthetic pyrethroid insecticide, was evaluated through assessment of the behavioral development of F1-progeny of mice. Groups each of 30 male and 30 female ICR (CD-l) mice, as F0-generation, were given 0, 2.5, 5, and 10mg/kg/day cypermethrin in corn oil orally for 4 weeks/5 days in a week before mating. Behavioral endpoints of motor reflexes, motor coordination, and activity were evaluated in F1-progeny. Clinical signs of toxicity including salivation, hyperactivity, and tremors which attributed to cypermethrin were observed in the F0-mice treated with 10mg/kg/day. A significant delay in the development of pinna detachment, down appearance, and eye opening of 48, 59, and 27 pups (47, 64, and 39%, respectively) was observed in the high dose group. Reduction of body weight became significantly evident only for F0-females either during treatment or gestation and lactation periods for the high dose group. Significant differences in the development of reflexes, swimming ability, and open-field activity were evident in the offspring for the 10mg/kg/day dose group compared to the control group. These results show that cypermethrin at dose level of 10mg/kg/day can induce a significant risk to the offspring following treatment of F0-mice before mating. The NOAEL obtained in this study for the effects of cypermethrin on the development of the F1-progeny is 5mg/kg/day.