Autism spectrum disorder-like behaviors in developing zebrafish exposed to particulate matter.

Researchers used zebrafish to study whether air pollution particles might cause autism-like behaviors. They exposed young fish to pollution particles and watched their behavior for nearly two weeks. They also tested whether melatonin (a natural sleep hormone) could help protect against any harmful effects. The pollution particles didn't cause the same behavior changes as a chemical known to cause autism-like symptoms in fish. Melatonin didn't help protect the fish from either substance.

This zebrafish study investigated whether exposure to particulate matter (PM), a component of air pollution, could produce autism spectrum disorder-like behaviors. Zebrafish larvae were exposed to PM standard reference material for 5 days starting 6 hours after fertilization, with behavioral assessments conducted over 13 days. The study also tested melatonin as a potential protective intervention and compared results to valproic acid (VPA), a known autism-inducing agent. Results showed that PM exposure did not produce behaviors similar to VPA exposure, and there were no additive effects when PM and VPA were combined.

Melatonin supplementation did not protect against behavioral impacts from either PM or VPA exposure.

Results suggest the relationship between air pollution and autism may be more complex than direct behavioral causation. Questions simple environmental exposure models and challenges melatonin as a protective intervention. Further research needed to understand phenotypic presentations of environment-autism associations.

Animal model findings may not translate to humans. Sample size not reported. Single PM type tested. Limited behavioral assessment timeframe. Unclear which specific behaviors were measured and how they relate to human ASD presentations.

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders that can impact communication and social behaviors. Evidence suggests that the causes of ASD are likely a combination of genetic and environmental factors, such as air pollution. Particulate matter (PM) is the solid and liquid portion of air pollution that can vary in size and has been associated with many health impacts, including cardiorespiratory impacts, and has more recently been found to be associated with the prevalence of ASD. However, little is known about the phenotypic presentations of this association between PM and ASD, therefore, the zebrafish (Danio rerio) model was employed to study behaviors often associated with ASD as a result of PM exposure.

Zebrafish larvae were exposed for a total of 5 days to PM standard reference material (SRM1649b) and a commonly used home remedy, melatonin, beginning at 6 h post-fertilization and various behavioral assays were performed on subsequent days for a total of 13 days. Observed and quantified behaviors were compared to a positive control, valproic acid (VPA). Generally, PM exposure did not elicit behavior resembling that of VPA exposure and the interactions between PM and VPA did not induce additive or synergistic behavioral patterns, as expected. Melatonin supplementation did not ameliorate most of the observed behavioral impacts of PM or VPA exposure.

These results have prompted additional questions about the phenotypic presentations of ASD as a result of PM exposure and contribute to growing knowledge about disease-environment interactions.