Teratological effects of Chlorpyrifos in mice

Introduction: chlorpyrifos (cpf), an organophosphate insecticide, was evaluated for potential teratogenic effects in mice. a single oral dose of insecticide (i.e. 72, 36 18 or 9 mg/kg) was given to the pregnant females on gestation day6 (gd6). these doses correspond 50, 25, 12.5 and 6.25% to the calculated ld50 value (144 mg/kg) for the pregnant mice. no signs of overt toxicity were observed at any of these doses. method and materials: fetuses recovered from 18, 36 and 72 mg/kg groups showed a variety of morphological defects i.e. microcephaly, hydrocephaly, agnathia, anophthalmia, enlarged meningio-encepahlocoele, spina-bifida, meromelia, micromelia, drooping wrists, rudimentary or kinky tails, round back, twisted spine, tortuous-limbs, flipper feet and sacral hygromas. fetuses recovered from vehicle treated and 9mg/kg groups were apparently normal. results: statistical analysis of the data based on single factor anova and duncan’s multiple range test have shown a dose dependent decrease in litter size (p < 0.001) along with averaged per litter: fetal weight (p < 0.01) and crown rump length (p < 0.05). the extent of ossification in embryonic skeleton decreased progressively with increased maternal cpf exposure. conclusion: based on these findings we conclude that, if treated on gd6, a single oral dose of 18 mg/kg cpf (12.5% of ld50) may lead to several craniofacial and skeletal anomalies in developing mice embryos, whereas its fetotoxic role is fairly dose dependent embryos.