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Cresto N, Courret M, Génin A, Martin CMP, Bourret J, Sakkaki S, de Bock F, Janvier A, Polizzi A, Payrastre L, Ellero-Simatos S, Audinat E, Perroy J, Marchi N. Continuous low-level dietary exposure to glyphosate elicits dose and sex-dependent synaptic and microglial adaptations in the rodent brain. Environ Pollut 2024; 345:123477. [PMID: 38307239 DOI: 10.1016/j.envpol.2024.123477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 01/19/2024] [Accepted: 01/30/2024] [Indexed: 02/04/2024]
Abstract
Prolonged exposure to low levels of dietary contaminants is a context in modern life that could alter organ physiology gradually. Here, we aimed to investigate the impact of continuous exposure to acceptable daily intake (ADI) and non-observable adverse effect level (NOAEL) of glyphosate from gestation to adulthood using C57BL/6J mice and incorporating these levels into their food pellets. From adulthood, we analyzed neurophysiological and neuro-glia cellular adaptations in male and female animals. Using ex-vivo hippocampal slice electrophysiology, we found a reduced efficacy of Schaffer collateral-to-CA1 excitatory synapses in glyphosate-exposed dietary conditions, with ADI and NOAEL dose-dependent effects. Short-term facilitation of excitatory synaptic transmission was specifically increased in NOAEL conditions, with a predominant influence in males, suggesting a reduced probability of neurotransmitter release. Long-term synaptic potentiation (LTP) was decreased in NOAEL-exposed mice. Next, we explore whether these neurophysiological modifications are associated with neuro-glia changes in the somatosensory cortex and hippocampus. High-resolution confocal microscopy analyses unveil a dose-dependent increased density of excitatory Vglut1+ Homer1+ synapses. Microglial Iba1+ cells displayed a shortening of their ramifications, a sign of cellular reactivity that was more pronounced in males at NOAEL levels. The morphology of GFAP+ astrocytes was generally not modified. Finally, we asked whether mouse-specific cross-correlations exist among all data sets generated. This examination included the novel object recognition (NOR) test performed before ex vivo functional and immunohistochemical examinations. We report a negative linear regression between the number of synapses and NOR or LTP maintenance when plotting ADI and NOAEL datasets. These results outline synaptic and microglial cell adaptations resulting from prenatal and continuous dietary low levels of glyphosate, discernible in, but not limited to, adult males exposed to the NOAEL. We discuss the potential significance of these findings to real-world consumer situations and long-term brain resilience.
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Affiliation(s)
- Noemie Cresto
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Margot Courret
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Athénaïs Génin
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Céline Marie Pauline Martin
- Toxalim (Research Centre in Food Toxicology), INRAE, ENVT, INP-Purpan, UPS, Université de Toulouse, Toulouse, France
| | - Julie Bourret
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Sophie Sakkaki
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Frederic de Bock
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Alicia Janvier
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Arnaud Polizzi
- Toxalim (Research Centre in Food Toxicology), INRAE, ENVT, INP-Purpan, UPS, Université de Toulouse, Toulouse, France
| | - Laurence Payrastre
- Toxalim (Research Centre in Food Toxicology), INRAE, ENVT, INP-Purpan, UPS, Université de Toulouse, Toulouse, France
| | - Sandrine Ellero-Simatos
- Toxalim (Research Centre in Food Toxicology), INRAE, ENVT, INP-Purpan, UPS, Université de Toulouse, Toulouse, France
| | - Etienne Audinat
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Julie Perroy
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Nicola Marchi
- Institute of Functional Genomics, University of Montpellier, CNRS, INSERM, Montpellier, France.
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