Oxidative stress biomarkers for assessing the synergistic toxicity of emamectin benzoate and cyantraniliprole on liver function.

Multiple pesticide residues in agricultural products and environments, especially those with synergistic toxicity, pose a potential risk to human health. We observed a remarkable increase in serum biochemical parameters related to rat liver function when rat liver was exposed to the binary mixture of emamectin benzoate and cyantraniliprole. The present study aimed to investigate the toxicity interactions and underlying mechanisms of the binary mixture by using an L-02 cell model and metabolomics analysis. Cytotoxicity tests have shown that binary mixtures of emamectin benzoate and cyantraniliprole produced either additive or synergistic toxic effect on the cell viability of the human hepatic epithelial cell line L-02. The interaction within the binary mixtures resulted in the production of excessive reactive oxygen species (ROS) and malondialdehyde, as well as overexpression of antioxidant enzyme activities. The synergism was driven by aggravated production of ROS, leading to an imbalance in mitochondrial oxidation and energy metabolism, suggesting the possible use of ROS as an effective toxicity endpoint. Based on the benchmark dose calculated to determine the combined toxicity threshold, the model-averaged estimates of the benchmark dose lower confidence limits (4.74-9.58 mmol/L) of the binary mixtures at concentration ratios of 3:15, 3:45, 4:15, and 4:45 were 20% more toxic than their individual active ingredients. These findings have important implications for risk assessments of pesticide residue in food and highlight the need to consider concentration ratios and oxidative stress endpoints in such assessments.