Ecotoxicological evaluation of the UV-filter octocrylene (OC) in embryonic zebrafish (Danio rerio): Developmental, biochemical and cellular biomarkers.

Octocrylene (OC), an UV-filter (OUVF) is used in many cosmetic products to protect the skin against the harmful effects of UV radiation. Octocrylene has been detected in the environment and become an emerging contaminant of concern. However, the eco-toxicological data on octocrylene and their molecular effects and mechanism of action on freshwater fish are very limited. In this research work, the potential toxicity of octocrylene and its mechanisms on morphology, antioxidant and AChE activity, apoptosis, and histopathological changes were investigated in embryonic zebrafish (Danio rerio) at different concentrations (5, 50 and 500 μg/L). Embryos/larvae (96 hpf) treated with 50 and 500 μg/L of OC caused developmental abnormalities, and decreased hatching rate and heartbeat rate. The oxidative damage (LPO) and antioxidant enzyme (SOD, CAT and GST) activities were apparently elevated (P < 0.05) at the highest test concentration (500 μg/L). However, acetylcholinesterase (AChE) activity was significantly inhibited at the highest test concentration. Also, OC induced apoptosis in a dose-dependent manner. The zebrafish exposed to 50 and 500 μg/L showed histopathological changes including elongated yolk sac, swim bladder inflammation, muscle cell degeneration, retinal damage and pyknotic cells. In conclusion, octocrylene has induced oxidative stress at environmentally relevant concentrations leading to developmental toxicity, neurotoxicity, and histopathological damage in zebrafish embryos/larvae.