Evaluation of the genotoxicity and fetal toxicity of the herbicide Paraquat

Abstract

The genotoxicity and fetal toxicity of the herbicide Paraquat was assessed in female mice treated with acute subcutaneous doses of the herbicide at different stages of pregnancy. The micronucleus test (MN) in peripheral blood erythrocytes and an evaluation of embryonic losses were applied. The results of the present work demonstrate that a single acute treatment in the period after-implantation did not produce a significant reduction in the size of the offspring at the lower dosage tested, 10 mg/kg bw (body weight). Genotoxicity was observed at 24 and 30 hours after treatment in animals receiving this dosage on the ninth and third day of pregnancy respectively. Our data suggest that the in vivo treatment with the lower herbicide dose induces embryonic losses in females exposed to the agent during the pre-implantation period. The dose of 20 mg/kg bw did not show genotoxic effects 24 hours after treatment, probably having induced cellular defenses due to high toxicity of the herbicide. This dose subsequently caused the death of the animals, hindering the analyses of MN at 30 hours post-treatment and of fetal toxicity determinations.