Silver nanoparticles (AgNPs) are a popular engineered nanomaterial widely used in industry. Despite the benefits they bring to society, AgNPs are not neutral to human health. The aim of this study was to evaluate the effects of a single intravenous dose (5 mg/kg
body weight) of 20 nm AgNPs on
steroid metabolism and redox balance in the testes of adult rats. The effects were evaluated 1 day or 28 days after intervention and compared with saline-treated animals. Decreased
aromatase and
estrogen receptor α levels (by 21% and 27%, respectively) were observed 1 day after AgNPs administration, while increased
testosterone, increased
dihydrotestosterone levels, higher
androgen receptors and higher
aromatase expression in Leydig cells (by 43%, 50%, 20% and 32%, respectively) as well as lower (by 35%)
androgen receptor protein levels were observed 28 days after exposure to AgNPs compared to control groups. The AgNPs treatment resulted in decreased
superoxide dismutase activity, decreased GSH/
GSSG ratio, and increased
glutathione reductase activity (by 23%, 63% and 28%, respectively) compared to control animals, irrespective of the time of measurement. Increased (by 28%) intratesticular
lipid hydroperoxides level was observed 1 day after AgNPs exposure, while decreased (by 70%) GSH and increased (by 43%)
7-ketocholesterol levels were observed 28 days
after treatment compared to control animals. Conclusions: AgNPs exposure caused redox imbalance in the gonads shortly after AgNPs administration, while a longer perspective AgNPs exposure was associated with impaired
androgen metabolism, probably due to increased oxidative stress.