Haloxyfop-P-methyl induces developmental defects in zebrafish embryos through oxidative stress and anti-vasculogenesis

Haloxyfop-P-methyl, an aryloxyphenoxypropionate herbicide, is widely used to eliminate unwanted plants by inhibiting lipid synthesis and inducing oxidative stress. Since haloxyfop-P-methyl targets are limited within plants, few negative side effects on non-target crops have been reported. However, dissolved haloxyfop-P-methyl in rain or groundwater contaminates aquatic environments and affects marine ecosystems. In the present study, treatment with haloxyfop-P-methyl for 48 h induced developmental deficiencies in the eyes and bodies of the zebrafish embryos as a whole and was also linked to increases in the incidence of pericardial edema. Additionally, haloxyfop-P-methyl treatment decreased hatching ratio, embryo viability, and heart rate, while simultaneously increasing the expression levels of apoptotic and inflammatory genes. Moreover, haloxyfop-P-methyl hampered vasculogenesis in the embryos through down-regulation of functional genes, and disruption of vessel formation caused neurodegeneration in the olig2-positive notochord. Collectively, this study newly discovered the oxidative stress-related toxic mechanism of haloxyfop-P-methyl during embryonic development through anti-vasculogenesis, which suppresses neurogenesis of the notochord. This toxicity assessment of haloxyfop-P-methyl on embryogenesis may contribute to establishment of safety profiling of herbicide and to support hazard control in aquatic environment.