Indigo dyes: Toxicity, teratogenicity, and genotoxicity studies in zebrafish embryos

• Published in: Mutation research. Genetic toxicology and environmental mutagenesis Vol. 896; p. 503752
• Main Authors: Porkodi, M., Brahmane, Manoj P., Pathan, Mujahidkhan A., Poojary, Nalini, Singh, Shubra, Harshavarthini, M., Nagpure, N.S.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2024
• Subjects: Animals; Coloring Agents - toxicity; Comet Assay; DNA damage; DNA Damage - drug effects; DNA repair genes; Embryo, Nonmammalian - drug effects; Gene expression; Histopathology; Indigo Carmine - toxicity; Mutagenicity Tests; Teratogens - toxicity; Water Pollutants, Chemical - toxicity; Zebrafish - embryology; DNA repair genes; Histopathology; Gene expression; DNA damage; Comet assay
• ISSN: 1383-5718; 1879-3592; 1879-3592
• DOI: 10.1016/j.mrgentox.2024.503752

Wastewater released by textile dyeing industries is a major source of pollution. Untreated wastewater released from indigo dyeing operations affects aquatic ecosystems and threatens their biodiversity. We have assessed the toxicity of natural and synthetic indigo dye in zebrafish embryos, using the endpoints of teratogenicity, genotoxicity, and histopathology. The zebrafish embryo toxicity test (ZFET) was conducted, exposing embryos to ten concentrations of natural and synthetic indigo dyes; the 96-hour LC50 values were approximately 350 and 300 mg/L, respectively. Both dyes were teratogenic, causing egg coagulation, tail detachment, yolk sac edema, pericardial edema, and tail bend, with no significant difference in effects between the natural and synthetic dyes. Both dyes were genotoxic (using comet assay for DNA damage). Real-time RT-PCR studies showed upregulation of the DNA-repair genes FEN1 and ERCC1. Severe histological changes were seen in zebrafish larvae following exposure to the dyes. Our results show that indigo dyes may be teratogenic and genotoxic to aquatic organisms, underscoring the need for development of sustainable practices and policies for mitigating the environmental impacts of textile dyeing. •Natural and synthetic Indigo dyes induced acute toxicity in zebrafish embroys.•The 96 h LC50 estimates revealed that synthetic indigo was more embryotoxic.•Egg coagulation was the most pronounced teratogenic malformation.•The indigo dyes induced DNA damage and upregulation of DNA repair genes.