Pyriproxyfen does not cause microcephaly or malformations in a preclinical mammalian model.

Area of Science:

• Toxicology
• Developmental Biology
• Public Health Entomology

Background:

• Pyriproxyfen is a key insecticide used in Brazil to control mosquito vectors transmitting Dengue Fever, Chikungunya Fever, and Zika virus.
• Concerns regarding potential developmental toxicity, including microcephaly, necessitate rigorous safety assessments of pyriproxyfen.

Purpose of the Study:

• To evaluate the toxicological profile of pyriproxyfen concerning reproductive performance, embryo-fetal development, and DNA integrity in a preclinical mouse model.
• To investigate whether pyriproxyfen exposure is associated with adverse head measurements or genotoxicity.

Main Methods:

• Thirty pregnant mice were allocated into three groups: a control group and two groups receiving different doses of pyriproxyfen via gavage during gestation.
• Parameters assessed included maternal and embryo-fetal development, biometric data, head measurements, and DNA integrity (micronucleus test).

Main Results:

• No significant differences were observed in reproductive performance or embryo-fetal development between control and pyriproxyfen-treated groups, indicating a lack of maternal or developmental toxicity.
• While most head measurements were unaffected, a slight increase in anterior/posterior and glabella/external occipital protuberance measurements was noted.
• An increase in micronuclei was observed only at 72 hours post-exposure in the lowest dose group, suggesting minimal genotoxic potential.

Conclusions:

• Pyriproxyfen does not appear to be related to the occurrence of microcephaly.
• The study infers that pyriproxyfen does not alter reproductive performance, embryo-fetal development, or significantly impact DNA integrity at the tested doses.