en Teratological Effects of Chlorpyrifos in Mice عمومى General پژوهشي Research <span style="font-weight: bold">Introduction:</span> 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. <br> <span style="font-weight: bold">Method and Materials:</span> 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. <br><span style="font-weight: bold">Results: </span>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. <br><span style="font-weight: bold">Conclusion:</span> 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. Chlorpyrifos, Teratogenesis, Feto-Toxicology Chlorpyrifos, Teratogenesis, Feto-Toxicology 3 3 http://ijt.arakmu.ac.ir/browse.php?a_code=A-10-2-3&slc_lang=en&sid=1 Khawaja Raees Ahmad Khawaja Raees Ahmad khawajaraees@hotmail.com 10031947532846003637 10031947532846003637 Yes Department of Biological Sciences, Assistant Professor of Zoology University of Sargodha, Sargodha. Pakistan Department of Biological Sciences, Assistant Professor of Zoology University of Sargodha, Sargodha. Pakistan Asmatullah Asmatullah 10031947532846003638 10031947532846003638 No Department of Biological Sciences, Associate Professor of Zoology University of the Punjab, Lahore. Pakistan Department of Biological Sciences, Associate Professor of Zoology University of the Punjab, Lahore. Pakistan