Similarities between the Effects of Prenatal Chlorpyrifos and Valproic Acid on Ultrasonic Vocalization in Infant Wistar Rats.

Miguel Morales-Navas,Cristian Pérez-Fernández,María Teresa Colomina,Xavier Leinekugel,Ainhoa Sánchez-Gil,Fernando Sánchez-Santed,Sergio Castaño-Castaño

doi:10.3390/ijerph17176376

Abstract

Background: In recent years, ultrasonic vocalizations (USV) in pups has become established as a good tool for evaluating behaviors related to communication deficits and emotional states observed in autism spectrum disorder (ASD). Prenatal valproic acid (VPA) exposure leads to impairments and social behavior deficits associated with autism, with the effects of VPA being considered as a reliable animal model of ASD. Some studies also suggest that prenatal exposure to chlorpyrifos (CPF) could enhance autistic-like behaviors. Methods: In order to explore these similarities, in the present study we tested whether prenatal exposure to CPF at GD12.5–14.5 produces effects that are comparable to those produced by prenatal VPA exposure at GD12.5 in infant Wistar rats. Using Deep Squeek software, we evaluated total number of USVs, latency to the first call, mean call duration, principal frequency peak, high frequency peak, and type of calls. Results: Consistent with our hypothesis, we found that exposure to both CPF and VPA leads to a significantly smaller number of calls along with a longer latency to produce the first call. No significant effects were found for the remaining dependent variables. Conclusions: These results suggest that prenatal exposure to CPF could produce certain behaviors that are reminiscent of those observed in ASD patients.

Highlights

Vertebrates are usually able to produce acoustic signals to transmit all types of information, from characteristics related to themselves, such as identity, mood, and status, to a wide variety of environmental situations
No significant differences in body weight were found between the groups (Figure 1a)
The present study explored the effects on ultrasonic vocalization following prenatal treatment with a subclinical dose of CPF, in a period equivalent to the first trimester of human gestation [28]

Summary

Introduction

Vertebrates are usually able to produce acoustic signals to transmit all types of information, from characteristics related to themselves, such as identity, mood, and status, to a wide variety of environmental situations. Due to the multi-functional nature of such signals, a wide variety of different sounds can be found. In rats, such sounds are referred to as vocalizations. Ultrasonic vocalizations (USV) in pups has become established as a good tool for evaluating behaviors related to communication deficits and emotional states observed in autism spectrum disorder (ASD). Results: Consistent with our hypothesis, we found that exposure to both CPF and VPA leads to a significantly smaller number of calls along with a longer latency to produce the first call. Conclusions: These results suggest that prenatal exposure to CPF could produce certain behaviors that are reminiscent of those observed in ASD patients

Methods

Discussion

Conclusion