Comparative assessment of silver nanoparticle and silver nitrate toxicities in Mytilus galloprovincialis

Silver nanoparticles (AgNPs) and Ag⁺ ions are both detected in aquatic environments, posing potential risks to marine ecosystems. Mytilus galloprovincialis is an effective model for monitoring marine environments. In this study, AgNPs were synthesized using a chemical approach, and to distinguish the toxicological effects of AgNPs and AgNO₃ in M. galloprovincialis, experiments were conducted using various treatments (control, AgNO₃, AgNPs, and AgNPs + cysteine). Our findings revealed that the uptake rate of AgNPs and AgNO₃ was different, they predominantly accumulated in the hepatopancreas and gills. qRT-PCR analysis showed varying degrees of alterations in immune genes of HSPA12A, TCTP, sHSP22, sHSP24.1, P63, Bcl-2, and Ras. Histopathological analysis demonstrated disrupted epithelial cell arrangements and connective tissue damage in the hepatopancreas, with the AgNPs exhibiting the most severe damage compared to AgNO₃. In addition, AgNPs significantly induced oxidative stress in hemocytes compared to AgNO₃, resulting in elevated apoptosis rates. These findings contribute to a deeper understanding of the AgNPs and AgNO₃ interactions in marine environments and provide a theoretical basis for the evaluation of marine pollution and biomonitoring strategies.