Kırıcı, Muammer; Erdoğan, Mehmet Kadir; Caf, Fatma; Gündoğdu, Ramazan; Taysı, Mehmet Reşit; Kırıcı, Mahinur; Sökmen, Teoman Özgür; Kaya, Bülent; Toy, Yusuf

The rapid increase in the use of nanoparticles in various sectors necessitates understanding their potential biological effects on aquatic organisms. In particular, the biosafety profiles of plant-derived biosynthetic nanoparticles, developed as environmentally friendly alternatives, are still known to a limited extent. In this study, the cytotoxic and apoptotic effects of iron (Fe), copper (Cu), and silver (Ag) nanoparticles obtained by green synthesis using sage ( Salvia officinalis ) leaf extract on rainbow trout ( Oncorhynchus mykiss ) gonad cell line (RTG-2) were investigated. The structural and morphological properties of the synthesized nanoparticles were characterized by UV–Visible spectroscopy, FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM)-EDX, and zeta potential analyses. Cell viability and apoptosis-related protein responses were assessed following nanoparticle exposure. The results showed that all metal nanoparticles produced a concentration-dependent cytotoxic effect in RTG-2 cells. Silver nanoparticles (AgNPs) exhibited the strongest cytotoxic effect, significantly reducing cell viability, especially at concentrations of 50 µg/mL and above. Apoptosis analysis revealed that different toxicity mechanisms were activated depending on the metal type. While AgNPs strongly suppressed BCL2 expression and appeared to enhance apoptosis-related responses, CuNPs and FeNPs were mainly associated with p53-mediated cellular stress signaling. In conclusion, it was shown that sage-derived metal nanoparticles produced metal-type-specific cytotoxic and apoptotic effects in fish gonad cells; these findings highlight the necessity of species- and metal-based approaches in the environmental risk assessment of green synthesis nanoparticles.