Many anthropogenic pollutants are under scrutiny due to potential links to clinical disorders. Zebrafish (Danio rerio) are an increasingly popular model animal for studying the effects of these substances on learning and behavior, in part due to close parallels between the genomes of zebrafish and humans. In this study, we investigate the impact of microplastics (MPs) on zebrafish locomotor behavior. MPs are small plastic particles that are typically characterized as less than 5 mm in length. MPs have recently generated concerns due to their ubiquitous presence in the biosphere, especially aquatic ecosystems, and their potential to accumulate in tissues of living organisms. In our experiment, wild-type zebrafish embryos were exposed to polystyrene MPs of 1 micron in diameter at sublethal concentrations of 0.1 mg/L and 1 mg/L. It has been demonstrated that zebrafish larvae ingest MPs of this size, which subsequently can enter tissue. At 120 hrs post fertilization, the zebrafish larvae were rinsed and then evaluated using the alternating light-dark assay. In this assay, the larvae underwent 10 min in light conditions followed by 10 min in dark conditions continuously for 3 light-dark cycles. Total distance moved by the larvae was tracked in 1 sec time blocks using the Zantiks MWP system. Control larvae typically exhibited higher locomotion in the dark compared to the light, and notable startle responses were observed between transitions from light to dark. It was hypothesized that MPs would impede neurotransmission by inhibiting breakdown of acetylcholine, leading to decreased sensitivity in response to changes in brightness. Preliminary results indicated elevation of activity in light conditions with exposure to MPs. These findings would warrant further investigation into potential neurotoxic effects induced by MPs, especially since the mechanisms governing these effects are largely unknown. In addition, synergistic toxicity between MPs and other environmental pollutants should be considered to better understand how MPs act as an interface for adsorption. Temperature manipulations can potentially illustrate the trend of ocean warming and the impact this has on aquatic wildlife.
Zheng, Henry,
"Effects of Microplastic Exposure on Behavior"
(2023).
Summer Research Symposium.
Brown Digital Repository. Brown University Library.
https://doi.org/10.26300/8q79-hy34
Each year, Brown University showcases the research of its undergraduates at the Summer Research Symposium. More than half of the student-researchers are UTRA recipients, while others receive funding from a variety of Brown-administered and national programs and fellowships and go …
