Hepatotoxicity of environmental acetamiprid and cadmium in Pelophylax nigromaculatus: An integrated analysis from histopathology to molecular mechanisms.

In agricultural ecosystems, pesticides and heavy metals often coexist as understudied threats to ecological health. Although traditional risk assessments focus on single contaminants, the combined effects, particularly on ecologically relevant amphibians such as Pelophylax nigromaculatus, remain poorly understood. Among these pollutants, the neonicotinoid acetamiprid and cadmium are widely detected in aquatic environments, yet their combined hepatotoxicity in adult amphibians has not been adequately investigated. In this study, we aimed to investigate the individual and combined toxic effects of acetamiprid and cadmium in P. nigromaculatus at environmentally relevant concentrations, employing an integrated multi-omics approach in conjunction with biochemical and histopathological evaluations. Individual exposures induced significant metabolic disruption and tissue injury. In contrast, co-exposure triggered a unique adaptive compensation network that maintained redox balance and redirected amino acid and nucleotide metabolism, thereby mitigating inflammatory activation and liver damage. Molecular docking simulations further revealed differential binding interactions of acetamiprid and an acetamiprid-cadmium complex with key compensatory proteins, providing a mechanistic basis for the attenuated toxicity under combined exposures. These results highlight the importance of incorporating mixture toxicity and life-stage-specific responses into ecological risk assessments, reveal unexpected adaptive pathways in amphibians exposed to complex pollutant scenarios, and emphasize the need for more comprehensive evaluations of interactions among environmental contaminants.