The effect of titanium dioxide nanoparticles on antioxidant gene expression in tilapia (Oreochromis niloticus)

• DOI: 10.1007/s11051-014-2369-3
• Publication Date: 2014-03-31T04:25:25Z
• Authors: Ruth Varela-Valencia; Nikte Gómez-Ortiz; Gerko Oskam; Romeo de Coss; Jorge Rubio-Piña; Marcela del Río-G...; Arnulfo Albores-M...; Omar Zapata-Perez
• Keywords: 0301 basic medicine; 03 medical and health sciences; 3. Good health

The reactivity of nanoparticles (NPs) in biological systems is well recognized, but there are huge gaps in our understanding of NP toxicity in fish, despite a number of recent ecotoxicity studies. Therefore, the aim of this research was to evaluate the effect of titanium dioxide NPs (TiO2-NPs) on antioxidant gene expression in the tilapia, Oreochromis niloticus. First, different sizes, shapes, and phases of TiO2-NPs were synthesized and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and dynamic light scattering (DLS). Fish were injected intraperitoneally with different concentrations (0.1, 1.0, 10.0 mg/L), sizes (7, 14, and 21 nm), and phases (anatase and rutile) of TiO2-NPs, and sacrificed 3, 6, 12, and 24 h after injection, when their livers were removed. Total RNA was extracted, and expression of the catalase (CAT), glutathione-S-transferase (GST), and superoxide dismutase (SOD) genes was assessed by real-time polymerase chain reaction (RT-PCR). The results showed that injection of 1.0 mg/L TiO2-NPs induced an initial mild increase in CAT, GST, and SOD gene expression in tilapia, after which transcript levels decreased. Fish injected with 7 and 14 nm TiO2-NPs showed an increase in antioxidant transcript levels 6 h after treatment. Finally, the rutile form generated stronger induction of the GST gene than anatase TiO2-NPs during the first 6 h after injection, which suggests that exposure to rutile causes higher levels of reactive oxygen species to be produced.