Acute exposure to environmentally relevant concentrations of pharmaceutical pollutants induces neurobehavioral toxicity in zebrafish (Danio rerio)

Abstract

Pharmaceutical waste from point and non-point sources enters, persists, or disseminates in the environment and is known as environmentally persistent pharmaceutical pollutants. Understanding the impacts of pharmaceutical pollutants on the environment and health is essential. This study investigates the behavioral impacts of pharmaceutical pollutants on aquatic organisms and delineates the possible nexus of oxidative stress. The male zebrafish were exposed to four major representative pharmaceutical pollutants, viz., acetaminophen, carbamazepine, metformin, and trimethoprim at environmentally relevant concentrations individually as well as in a mixture for seven days. Substantial alterations in social interaction, aggressive nature, novel tank exploration, and light and dark zone preferences were recorded and the degree varied to different pharmaceutical pollutants. The activity of oxidative stress markers, superoxide dismutase, glutathione-S-transferase, and catalase, was found to be suppressed to 66–20%, 42–25%, and 59–20% respectively with the elevated malondialdehyde generation (180–260%) compared to control. The activity level of acetylcholine esterase was found to be increased to 200–500% across all treatment groups. Despite the synergistic impacts of pharmaceutical pollutants on the whole system that could not be ascertained, this comprehensive study highlights their toxicity nature to induce neurobehavioral toxicity in zebrafish through oxidative stress mechanisms and altered cholinergic systems.

Keywords:

• Acute toxicity
• emerging contaminants
• neurobehavior
• oxidative stress
• pharmaceutical pollutants
• zebrafish

Acknowledgements

We are grateful to Dr. M.S. Mohamed Jaabir, Professor & Head, Department of Biotechnology, Microbiology and Bioinformatics, National College, Tiruchirappalli, India for providing all the necessary facilities to carry out the experiments. Our sincere thanks to Dr. Shanmugam Achiraman, Professor, Department of Environmental Biotechnology, Bharathidasan University, India for his suggestions on experiments. Our special thanks to Mr. Satheeswaran. B and Ms. Srija Babu, Ph.D. Research Scholars, Molecular Toxicology Laboratory, Bharathiar University, India for their help in analyzing the behavioral trajectory data. This project did not receive any specific grant from funding agencies.

Author contributions

VD designed the research work, analyzed the data, and drafted the final manuscript. SV and SE carried out the experiments and analyzed the data. EP revised and improved the manuscript. The manuscript was prepared with insights from all the authors.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.