In Vitro Effect of Silver Engineered Nanoparticles on Human Spermatozoa

Abstract

Silver (Ag) NPs are among the most commercialized NPs due to their antimicrobial potential. They are highly at- tractive for possible applications in manufacture of medical device. However there is a serious lack of information concerning their impact on the human health and the environment. Moreover studies on the effects of NPs on ejaculated sperm are rather limited. For these reasons our study explored the in vitro effects of Ag NPs on human ejaculated spermatozoa. Ag NPs have been produced, characterized, and furnished by Colorobbia Industry, Sovigliana (Vinci, Florence, Italy). Aliquots of total semen were incubated at 37&deg;C for 60 minutes (min) and 120 min at the concentration of 125 &mu;M, 250 &mu;M, and 500 &mu;M of engineered Ag NPs. The control was represented by specimens of semen samples treated with the same procedure without NPs. After the incubations, sperm motility was evaluated following WHO guidelines and sperm viability was eval- uated by Eosin Y test. At the end of incubation with Ag NPs the samples were processed by a Field Emission Gun-based Scanning Transmition Electron Microscope/ Energy Dispertion Spectrometry (STEM/EDS). We observed that sperm motility percentage was significantly reduced in semen samples treated with 125 &mu;M, 250 &mu;M and 500 &mu;M of Ag NPs after 60 min and 120 min of incubation respect to controls (P<0.001; P<0.01, 125 &mu;M at 60 min). Sperm viability percentage significantly decreased in a progressive manner after 125 &mu;M (P<0.05), 250 &mu;M (P<0.05) and 500 &mu;M (P<0.001) Ag NPs incubation at 60 min and 120 min. We did not find any significant difference between the values assessed after 60 min of NPs incubation and those estimated after 120 min of incubation. In the control samples, the sperm motility and the sperm viability percentages significantly decreased after 120 min of incubation (P<0.001) respect to the basal values. Ag NPs were undetectable in all treated samples by STEM/EDS. These in vitro results show a decline in sperm motility and viability in even at the lowest concentration used and the cytotoxic effect occurs in a dose dependent manner. It is noteworthy that in each experiment, for each concentration of NPs used, the percentage of sperm viability was always higher than the percentage of sperm motility; it means that spermatozoa were viable but immotile. Moreover Ag NPs was undetectable in all the treated samples by STEM/EDS analysis. We may hypothesize that Ag NPs, under aqueous conditions, release Ag+ that could damage sperm membrane and/or penetrate inside the cells and interfere with disulphide bonds of proteins of the periassonemal structures of the sperm tail

The Effects of Nanomaterials as Endocrine Disruptors

“…The results of this study and the findings of Terzuoli [50], who suggested that the release of Ag + under aqueous conditions could damage sperm membrane, endorse the idea that the release of ions by metallic NPs or QDs may play a relevant role in the induction of endocrine impairments in in vitro and in vivo models. Dissolution processes, consisting in the release of metallic cations, are greater in NPs than in bulk materials and are influenced by numerous factors such as reduced size, high surface-to-mass ratio, high radii of curvature, and corresponding low coordinated atoms at the surface [168].…”

“…Similar results were obtained by Terzuoli et al . [50] in human spermatozoa treated with different doses (0–500 μM) of Ag-NPs. However, the toxic effects of NPs on germ cells were not confirmed by the studies of Rafeeqi and Kaul and Murugan et al .…”

“…Finally, in the aforementioned study carried out by Terzuoli et al . [50], increasing concentrations of Ag-NPs significantly reduced human sperm motility. Conversely, motility and acrosome reactions of bovine sperm cells were not affected by exposure to 7.35 mM of magnetic iron oxide NPs (Fe 3 O 4 -NPs) coated with poly(vinyl alcohol) [43], or to 2.5 mg/mL of europium hydroxide NPs (EuOH 3 -NPs) conjugated with polyvinyl alcohol or polyvinyl piyrolidone [44].…”

Acute reproductive toxicology after intratesticular injection of silver nanoparticles (AgNPs) in Wistar rats

“…Gromadzka-Ostrowska et al (2012) also suggested that the genotoxicity effects of systemic AgNPs observed in their study is pronounced in mature sperm cells in the epididymis. Another in vitro study with ejaculated sperm suggests AgNPs interfere with membrane receptors or cell signaling involved in sperm motility (Terzuoli et al 2012).…”

Silver acetate exposure: Effects on reproduction and post natal development

“…In vitro studies have demonstrated that metal ions, including silver may reduce normal sperm metabolism by inhibition of sperm creatine kinase and possibly contribute to infertility in men (Ghaffari and Motlagh, 2011). It has been reported that ionic silver has both "acute and significant effects" on spermatogenesis, the number of spermatogenic cells, the acrosome reaction (Miresmaeili et al, 2013) as well as on sperm motility and viability (Terzuoli et al, 2011); these observed effects were attributed to ionic silver inducing damage in the sperm membrane and/or penetrating the germ cells and interfering with sperm tail proteins and thus adversely impacting motility. In the present study, histological effects were not observed in glutaraldehyde-fixed plastic embedded testicular tissues nor were testicular weights from any treatment group significantly different than control values.…”