Neurobehavioral Tests In Offsprings After Prenatal Exposure To Cypermethrin And Methylparathion

Objective To identify adverse effects of neurobehavior in offspring of rats after pregnant exposure to Methylparathion and Cypermethrin.Methods 30 female Wistar rats weighing 120~200g and 70 male Wistar rats weighing 150~220g of 3-moths-old were mated on 6:00 pm. Onset of pregnancy was confirmed by the presence of spermatozoa in vaginal smears on the following morning, designated as gestation day 0 (GDO). Pregnant Wistar rats were divided randomly into 4 groups. Methylparathion and Cypermethrin were force-fed to pregnant rats from the first day to fifth day after conception. The dose levels of methylparathion and cypermethrin were 0, 0.0230, 0.0725, 0.2300mg/kgBW and 0, 0.8000, 2.5265, 8.0000mg/kgBW respectively. Double blind test was used in experiment. The test of cliff avoidance reflex, surface righting reflex, air righting reflex, auditory startle reflex, visual placing reflex and forelimb hanging were studied in offspring of Wistar rats. Meanwhile, spatial learning and memory was examined by Morris water maze in litters.Result The test of cliff avoidance reflex test in the high and middle dose group were lower than control group in fourth and fifth day (p<0.05) . The visual placing reflex test showed that the performance of high and low dose group was lower than controlgroup. No statistically significant difference the test of surface righting reflex, air righting reflex, auditory startle reflex and forelimb hanging as well as performance of Morris water maze was observed between treatment groups and control group.Conclusion Prenatal exposure to cypermethrin and methylparathion at the dose in this experiment, the maternal toxicity was not observed in all treatment groups. Compared to the control group, the cliff avoidance reflex and the visual placing reflex indexes of offspring in treatment groups were delayed. There is no difference in spatial learning and memory of litters in all treatment groups.