EFEITO PARADOXAL DE BAIXAS DOSES DE NANOPARTÍCULAS DE PRATA NA EXPRESSÃO TESTICULAR DE GENES RELACIONADOS COM A ESPERMATOGÊNESE, HORMÔNIOS SEXUAIS E FUNCIONALIDADE ESPERMÁTICA

Abstract

Silver nanoparticles (AgNPs) stand out in the medicine and industry areas by their antibacterial, antifungical and antiviral properties. The high degree of commercialization increases the concerns about potential toxicity in various systems including the reproductive tract. This study aimed to evaluate the reproductive toxicity of AgNPs in the selected parameters in a dose response curve on which the higher dose corresponded to LOAEL (lowest observed adverse effect level) previously established (15 μg/kg) in prepubertal Wistar rats as experimental model. It was evaluated the sperm production, the sperm reserves, the sperm transit time, the sperm functionality (acrosome and plasma membrane integrities, mitochondrial activity and sperm morphology). The mRNA expression in the testis was evaluated by reverse transcription followed by real-time polymerase chain reaction (RTqPCR) for androgen receptor (Ar), estradiol receptor α (Esr1), estradiol receptor β (Esr2), estrogen receptor 1 coupled to the G-protein (Gper) and aromatase (Cyp19a1) genes. It was measured the serum concentrations of testosterone and estradiol. The results were statistically analyzed by analysis of variance followed by Dunnet’s post-hoc test considering statistical differences when p<0,05. The exposure to AgNPs during the prepubertal period resulted in altered expression of the genes Ar, Gper and Esr1 related to the spermatogenesis control, and in the hormones levels. The sperm parameters were also altered. It is possible to concluded that AgNPs has non-linear dose-response effects acting as a potential endocrine disrupting chemical and causing reduction in male fertility.