[Cisplatin exposure induces immunotoxic effects in zebrafish]

Cisplatin (CDDP) is an anticancer drug widely used in clinical practice. The immunotoxic effects of CDDP residues in the environment on aquatic organisms remain unclear. This study aimed to evaluate the immunotoxic effects of CDDP at environmentally relevant concentrations on zebrafish and to verify the mediating role of the NF-κB signaling pathway. Using zebrafish as a model organism, we systematically investigated the toxicological consequences of CDDP exposure on the immune system. The results showed that CDDP significantly reduced the survival and hatching rates of zebrafish, with a median lethal concentration (LC₅₀) of 0.48 mg/L. In addition, CDDP induced developmental retardation, eye size reduction, and other morphological abnormalities in the larvae, as well as decreased spontaneous locomotion and disrupted light-dark rhythm. In terms of oxidative stress, CDDP exposure elevated reactive oxygen species (ROS) and malondialdehyde (MDA) levels, while decreasing glutathione (GSH) content and catalase (CAT) activity, which indicated impairment of the antioxidant defense system. Immunological analyses revealed abnormal recruitment of macrophages and neutrophils, dysregulated complement C3 levels, and persistent suppression of immunoglobulin M (IgM). Long-term exposure led to altered kidney function markers in adult zebrafish. From a mechanism perspective, CDDP markedly upregulated the expression of key genes in the NF-κB signaling pathway, driving excessive immune-inflammatory responses. These effects were observable even at the environmentally relevant concentration of 0.025 mg/L. This study provides a theoretical basis for elucidating the ecological risks and immunotoxic mechanisms of CDDP in aquatic environments.