Toxicity and metabolomics study of isocarbophos in adult zebrafish (Danio rerio).

Although isocarbophos is a widely used insecticide, its toxicity to aquatic organisms has not been well characterized. In this study, zebrafish were exposed to isocarbophos at concentrations of 50 µg L-1 and 200 µg L-1 to assess its bioaccumulation, metabolic disruption, and oxidative stress. Metabolomics analysis based on 1H NMR spectroscopy showed that 50 µg L-1 and 200 µg L-1 isocarbophos exposure induced increases in leucine, isoleucine, valine, and alanine compared to levels in the control. Lactate, creatine, and taurine were reduced in the 50 µg L-1 isocarbophos exposure group, and only lactate decreased in response to 200 µg L-1 isocarbophos. After zebrafish were exposed to 50 and 200 µg L-1 isocarbophos for 28 days, the activities of antioxidant enzymes (SOD, CAT, and GPx) and GSH contents decreased significantly in the liver. This result indicates that there was significant oxidative stress in the liver. Furthermore, changes in metabolite profiles significantly covaried with changes in several oxidative stress endpoints based on partial least squares regression. These results will contribute to the environmental risk assessment of isocarbophos and clarify the mechanism underlying its toxicity in zebrafish.