Avaliação da embriotoxicidade e resposta visual motora em zebrafish (Danio rerio) induzida por reteno

Abstract

Retene or RET (1-methyl-7-isopropylphenanthrene), a non-priority polycyclic aromatic hydrocarbon (PAH), is the most prevalent compound in cellulose combustion, although its toxic effects are not yet fully understood. The emission of compounds such as RET becomes especially concerning given the increase in forest fires. According to the National Institute for Space Research (INPE), in 2023 alone, more than 223,000 fires were recorded in Brazil, particularly in the Amazon, Cerrado, and Pantanal regions. Globally, the number of forest fires has also increased, contributing to the release of PAHs. In this context, this study investigated the embryotoxicity and neurotoxicity of RET using zebrafish embryos. Five RET concentrations were tested: 100 µg/L, 250 µg/L, 500 µg/L, 750 µg/L, and 1000 µg/L, in addition to two controls: 0.1% DMSO (negative) and 4 mg/L 3,4-dichloroaniline (positive). Eggs and larvae were evaluated for external morphology every 24, 48, 72, and 96 hours post-fertilization (hpf). Larvae at 7 days post-fertilization (dpf), previously treated with RET, were subjected to the optomotor response test subsequent analysis of gene expression. RET did not significantly alter the survival rate in any of the groups analyzed. However, it induced significant morphological malformations and consistent behavioral alterations, indicating sublethal neurotoxicity. The molecular data proved inconclusive.These findings position Retene as a compound of ecotoxicological concern, especially in chronic exposures during critical phases of animal development.