Genotoxic, biochemical, cytotoxic and biomolecular alterations in the early-life stage of zebrafish exposed to diphenyl ether.

Diphenyl ether (DE) is a chemical compound being used in a number of industries such as soap, detergents, perfumes, adhesive, dyes, herbicides and as a flame retardant in plastics, rubbers and textiles, etc. DE is the final debromination product of polybrominated diphenyl ethers (PBDEs) under anaerobic conditions. The present investigation evaluated the genotoxic, biochemical, histopathological, ultrastructural (SEM) and biomolecular (ATR-FTIR) changes in the zebrafish larvae after DE exposure. After the determination of 96 h LC₅₀ value zebrafish embryos were exposed to sublethal concentrations (¼ LC₅₀ and ½ LC₅₀) of DE. Significantly increased DNA damage in terms of tail length (TL), tail intensity (TI), olive tail moment (OTM) and tail moment (TM) was observed after the DE exposure to zebrafish larvae. Also, increased lipid peroxidation (MDA) and decreased FRAP activity were reported after DE exposure. The catalase (CAT), Glutathione-S-transferase (GST), and Acetylcholinesterase (AChE) activity were reported to be significantly increased and a decreased superoxide dismutase (SOD) activity was observed in DE-exposed groups. After DE exposure, Decreased cell viability and increased apoptosis were reported in zebrafish larvae. The histological and ultrastructural (SEM) analysis revealed the alterations in the zebrafish larvae exposed to DE. The ATR-FTIR study revealed the changes in the biomolecules such as DNA and protein after the DE exposure. The present study will help to understand the destructive aspects of DE in the early life stages of aquatic organisms and could be utilized to assess environmental risk.