Varying modalities of perinatal exposure to a pesticide cocktail elicit neurological adaptations in mice and zebrafish

Isabel Forner-Piquer (1) , Wendy Klement (1) , Giuseppe Gangarossa (2) , Emma Zub (1) , Frédéric de Bock (1) , Marine Blaquière (1) , Tangui Maurice (3) , Etienne Audinat (1) , Adèle Faucherre (1) , Frédéric Lasserre (4) , Sandrine Ellero-Simatos (4) , Laurence Gamet-Payrastre (4) , Chris Jopling (1) , Nicola Marchi (1)

1 IGF - Institut de Génomique Fonctionnelle
2 BFA (UMR_8251 / U1133) - Unité de Biologie Fonctionnelle et Adaptative
3 MMDN - Mécanismes moléculaires dans les démences neurodégénératives
4 ToxAlim-TIM - Toxicologie Intégrative & Métabolisme

Epidemiological indications connect maternal and developmental presence or exposure to pesticides with an increased risk for a spectrum of neurological trajectories. To provide pre-clinical data in support of this hypothesis, we used two distinct experimental models. First, female and male mice were fed immediately prior to mating, and the resulting pregnant dams were continously fed during gestation and lactation periods using chow pellets containing a cocktail of six pesticides at tolerable daily intake levels. Male and female offspring were then tracked for behavioral and in vivo electrophysiological adaptations. Second, a zebrafish model allowed us to screen toxicity and motor-behavior outcomes specifically associated with the developmental exposure to a low-to-high concentration range of the cocktail and of each individual pesticide. Here, we report anxiety-like behavior in aging male mice maternally exposed to the cocktail, as compared to age and gender matched sham animals. In parallel, in vivo electrocorticography revealed a decrease in gamma (40-80 Hz) and an increase of theta (6-9 Hz) waves, delineating a long-term, age-dependent, neuronal slowing. Neurological changes were not accompanied by brain structural malformations. Next, by using zebrafish larvae, we showed an increase of all motor-behavioral parameters resulting from the developmental exposure to 10 μg/L of pesticide cocktail, an outcome that was not associated with midbrain structural or neurovascular modifications as assessed by in vivo 2-photon microscopy. When screening each pesticide, chlorpyrifos elicited modifications of swimming parameters at 0.1 μg/L, while other components provoked changes from 0.5 μg/L. Ziram was the single most toxic component inducing developmental malformations and mortality at 10 μg/L. Although we have employed non-equivalent modalities and timing of exposure in two dissimilar experimental models, these outcomes indicate that presence of a pesticide cocktail during perinatal periods represents an element promoting behavioral and neurophysiological modifications. The study limitations and the possible pertinence of our findings to ecotoxicology and public health are critically discussed.

Mots clés: Low dosages; Mating and perinatal exposures; Mouse; Neurological outcome; Neurovascular structures; Pesticide cocktail; Zebrafish

Domaines: Sciences du Vivant [q-bio]; Neurosciences [q-bio.NC]; Toxicologie

Isabel Forner-Piquer, Wendy Klement, Giuseppe Gangarossa, Emma Zub, Frédéric de Bock, et al.. Varying modalities of perinatal exposure to a pesticide cocktail elicit neurological adaptations in mice and zebrafish. Environmental Pollution, 2021, 278, pp.116755. ⟨10.1016/j.envpol.2021.116755⟩. ⟨hal-03172903⟩