Long-term exposure to small-sized silica nanoparticles (SiO2-NPs) induces oxidative stress and impairs reproductive performance in adult zebrafish (Danio rerio)

Abstract

The widespread use of silica nanoparticles (SiO₂-NPs) in various industries, including chemical polishing, cosmetics, varnishes, medical, and food products, has increased the risk of their release into aquatic ecosystems. The toxic effects of small-size SiO₂-NPs on the reproductive performance of zebrafish (Danio rerio) have yet to be widely studied. This study aimed to investigate the impact of chronic exposure to small-sized (35 ± 6 nm) SiO₂-NPs on adult zebrafish through waterborne exposure to concentrations of 5 (SNP5), 10 (SNP10), 15 (SNP15), and 20 (SNP20) μg/L of SiO2-NPs for 28 days. Our results showed that SiO₂-NPs significantly impacted several biochemical parameters, including cholesterol, triglycerides, LDL, HDL, total protein, albumin, urea levels, and alkaline phosphatase and aspartate aminotransferase activity. Cortisol and glucose levels in the SNP20 group significantly differed from the control group. All the exposed groups, apart from SNP5, experienced a significant increase in their total immunoglobulin levels and lysozyme activity. While there was a considerable increase in the activity of catalase and superoxide dismutase in all exposed groups, the expression of antioxidant genes did not appear to be affected. Furthermore, the expression level of il8 was significantly higher in SNP5 and SNP10 than in other treatments. Exposure to SiO₂-NPs caused a decrease in gonad weight, absolute fecundity, and larval survival rate, particularly in the SNP20 group. The present study indicates that SiO₂-NPs can harm zebrafish and thus further research is necessary to assess their health and environmental risks.

Keywords: Environmental risks; Gene expression; Nanotoxicology; Reproductive toxicity; Silica nanoparticles.