Effects of Silver Nanoparticle Exposure to the Testicular Antioxidant System during the Prepubertal Rat Stage

Abstract

Humans and environments are constantly exposed to a wide range of commercial products containing silver nanoparticles (AgNPs) in their composition. The hypothalamic-pituitary-testicular (HP-testicular) axis is sensitive to low doses of AgNPs with repercussions in sperm functionality. The oxidative stress may be related to the pathogenesis of sperm alterations because Ag+ ions are released from AgNPs in the corporal fluids. This study aimed to investigate the effects of AgNP exposure in the antioxidant defense system. For this, the transcript expression and the activity of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), and glutathione reductase (GSR) enzymes were evaluated in the testis of rats exposed during the prepubertal period to increasing doses of AgNPs (1.875, 3.75, 7.5, or 15 μg of AgNPs/kg). The higher dose of AgNPs (15 μg/kg) investigated promoted increases in the activity of CAT, GPX, and GSR enzymes and in the expression of Gpx4 var1 transcript. The exposure to 7.5 μg/kg of AgNP increased the Gpx4 var1 mRNA expression. In the group that received 3.75 μg of AgNP/kg, the expression of Sod1, Gpx4 var2, and Gsr transcripts was decreased while the Gpx4 var1 mRNA expression was augmented. The lower dose of AgNPs tested (1.875 μg/kg) increased the expression of Cat and Gpx4 var1 transcripts. Thus, AgNP alters the expression and activity of the antioxidant enzymes in a nonmonotonic dose–response curve and directly or indirectly modulates the events related to spermatogenesis process.

Graphene Oxide–Silver Nanoparticle Nanocomposites Induce Oxidative Stress and Aberrant Methylation in Caprine Fetal Fibroblast Cells

“…AgNPs with different sizes and surface coatings or without coatings are likely to contribute to these different results. Lopes et al [38] reported that coated AgNPs have a better dispersion ability and are exposed to cells in a better way than non-coated AgNPs. In addition, the toxicity level varies among the type and origin of the cell lines.…”

Graphene oxide-silver nanocomposites induce oxidative stress and apoptosis in caprine fetal fibroblast cells

“…AgNPs with different sizes and surface coatings or without coatings are likely to contribute to these different results. Lopes et al [43] reported that coating-AgNPs had a better dispersion than AgNPs and was more fully exposed to the cells. When compared to L02 cells, HepG2 cells are more sensitive to AgNPs at the exposure level of 20-160 μg/mL [44].…”

Toxicity mechanisms of nanoparticles in the male reproductive system

“…A histological study has also shown that graphene oxide exposure was associated with structural damage in the testis, which included atrophy of seminiferous tubules with a reduction in germinal epithelium, germ cell loss, and vacuolization (Nirmal et al 2017). It was reported that male rats exposed to silver nanoparticles (AgNPs) induced alterations in the testis seminiferous tubule morphometry (Lopes et al 2019). Cerium oxide nanoparticles (CeO 2 NPs) revealed congestion and degeneration of seminiferous tubules and decreased sperm motility and count and increased total sperm abnormality in mice (Adebayo et al 2018).…”