Histopathological alteration in Zebrafish: Unravelling the Effects of Long-Term Copper Oxide Nanoparticle Exposure

Copper Oxide nanoparticles (CuO-NPs) are widely used and they build up in the aquatic environment and can be harmful to aquatic life. Aquatic creatures are affected by CuO NPs, yet the consequences of these particles have not been well explored despite contentious toxicological results. Therefore, this study aimed to investigate the effects of chronic exposure to CuO-NPs on adult zebrafish. The study was carried out by conducting physicochemical characterization of commercially procured CuO-NPs using UV/Vis, ICP-OES spectroscopy, Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy(FTIR). Following characterization, adult zebrafish were chronically exposed to 0.5, 1, and 3 mg/l of CuO-NPs. Characterization revealed a heterogeneous population of nanoparticles in the size ranges of 10–50 nm. Oxidative stress indicators and functional markers were studied in addition to tissue histology. Chronic exposure to adult Fish at concentrations of 1 and 3 mg/l exhibited increased levels of stress compared to lower concentrations of 0.5 mg/l. Observations from histology showed that the extent of tissue damage and injuries increased with the concentration of CuO-NPs. In conclusion, chronic exposure to ≤50nm-sized CuO-NPs exhibited toxic repercussions in adult zebrafish.