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

Pyriproxyfen is used in Brazil to combat epidemics of Dengue Fever, Chikungunya Fever, and Zika virus. This study assessed the effects of pyriproxyfen on reproductive performance, embryo-fetal development, head measurements, and DNA integrity in a preclinical model. Thirty pregnant mice were divided into three groups (n = 10): control (drinking water-0.1 ml/10 g (body weight-b.w., gavage) and treated with pyriproxyfen 0.0002 mg/kg and 0.0021 mg/kg (b.w., gavage) during the gestational period. Analysis of biometric, reproductive performance and embryo-fetal development parameters related to control presented no significant differences, suggesting no maternal or embryo-fetal toxicity. Head measurements showed no differences except an increase in anterior/posterior measurement and glabella/external occipital protuberance. Analysis of DNA integrity showed an increase in micronucleus only at 72 h for the lowest dose group. Thus, we infer that pyriproxyfen is not related to the occurrence of microcephaly, nor does it alter reproductive performance, embryo-fetal development or DNA integrity.

Evaluation of the effects of the larvicides temephos on reproductive performance, embryofetal development and DNA integrity of Swiss mice.

Temephos is considered the gold standard by the Ministry of Health for controlling the larvae of the mosquito Aedes aegypti. The present study evaluated the effects of Temephos larvicide on the reproductive performance, embryo-fetal development and DNA integrity of Swiss mice. This study used 30 pregnant female mice: 10 were controls treated with drinking water at a dosage of 0.1 mL/10 g (body weight - b.w., administered orally - a.o.), and 20 were treated with Temephos at doses of 0.0043 mg/kg and 0.043 mg/kg (b.w., a.o.) during the gestational period. Statistical analysis showed that Temephos did not alter the biometric or reproductive parameters. Comparing the weight of the fetus to the stage of pregnancy demonstrated that the 0.0043 mg/kg dosage increased the size of the fetuses. No external malformations were detected. However, the 0.043 mg/kg dosage induced changes in the sternum, with the main change being the center of the sternum, xiphoid processes and absence of the manubrium. The other skeletal and visceral alterations did not differ from the control group and are considered variants of normality. The analysis of head measurements showed an increase in the anterior/posterior measurements of the glabella, the external occipital protuberance and the biauricular plane. The circumference and area of the head did not present significant differences. The micronucleus test showed only a 0.043 mg/kg increase in 48 h. Thus, it is considered that Temephos has a low teratogenic and genotoxic risk.