Toxicity testing of D, L-sulforaphane in a zebrafish model

Abstract

Sulforaphane (SFN) belongs to the group of isothiocyanates and is present in many cruciferous plants, especially broccoli. The positive properties of this bioactive molecule in the form of extracts have been shown in numerous studies and include antibacterial, cardioprotective, and neuroprotective effects, antioxidant and immunomodulatory effects, as well as positive effects in various cancers. However, the potential for harmful effects of SFN has not been sufficiently investigated, particularly for chemically obtained D,L-sulforaphane. This study aimed to investigate the toxicity of D,L-sulforaphane on zebrafish (Danio rerio) model. Wild (AB) strain embryos and zebrafish transgenic lines with fluorescently labeled liver cells (Tg(fabp:EGFP)) and endothelial cells of blood vessels (Tg(fli1:EGFP)) were used, treated with different concentrations of SFN (1 to 20 μg/mL). The survival of embryos, developmental toxicity, hepatotoxicity and cardiotoxicity were monitored for five days. A concentration of 20 μg/mL of D,L-sulforaphane caused the death of all embryos, while the median lethal concentration (LC50) was found to be 14.2 μg/mL. D,L-sulforaphane exhibited toxic effects at concentrations higher than 3 μg/mL, primarily on the development of the swim bladder (4 μg/mL), and growth and development of embryos (4.58 μg/mL), while harmful effects on the liver (liver size and yolk resorption) were observed at a concentration of 10 μg/mL. Effects on the cardiovascular system were not observed at concentrations from 1 to 10 μg/mL. The investigation of D,L-sulforaphane on zebrafish embryos showed that harmful effects occur at very low concentrations, indicating the need for further investigation of toxicological potential of this molecule.