P-056 The reproductive toxicity of alginate coated silver nano-rod on sperm
Authors: Nazari M , Shabani R , Shirazi R , Ajdari M , Mehdizadeh M 
Published: June 2022

Abstract

Study question
What is the toxic effects of Au@Ag core-shell NR on sperm function?

Summary answer
Although sperm count and morphology did not differ significantly, changing the shape and envelope of the silver nanostructure did not reduce its toxicity.

What is known already
Spermatogenesis is a developmental process of germ cell reproduction that depends on hormonal or dynamic interplays between sertoli cells and germ cells. Silver is the most common noble metal used in the synthesis of nanoscale materials, particularly in room sprays, cosmetics, toys, clinical catheters, and wound dressings. The increasing usability of silver nanoparticles (Ag NP) has increased human exposure. Many studies have demonstrated that Ag nanoparticles, depending on their shape, size, and concentration, have cytotoxic effects that reduce cell viability. The toxicity of silver Nano-Rod by deformation and coating with alginate has been studied.

Study design, size, duration
Forty-eight male mice were divided into five groups (two treatments, two shams, and one control). The treated groups received the Ag Nano-Rod at a dose of 1.5 mg/kg/day intraperitoneally for fourteen and thirty-five days. The sham groups were treated with identical amounts and days, and the control group received no material. Finally, the cauda epididymis of the animals was removed.

Participants/materials, setting, methods
In the present study, Ag Nano-Rod were characterized by HR-TEM, FT-IR, UV-visible, XRD and ICP-MS. Sperm analysis, including count, motility, viability, and morphology, was studied according to the criteria of WHO. A phase-contrast microscope was used to count the spermatozoa and assess their motility. Viability and morphology were examined by eosin-nigrosin and papanicolaou staining, respectively. TUNEL assay and gene expression for apoptotic and autophagic markers were also performed.

Main results and the role of chance
High magnification images TEM were obtained. According to this, the Ag nanostructure was rod-shaped and the average size of the particles was 50nm. The UV-visible confirms the formation of the synthesized nanosilver (rod shape). The change in nanostructure coating from CTAB to alginate was studied by FTIR analysis, and XRD proved the presence of silver in the composition. The results of sperm analysis showed that there was no significant decrease in sperm count and morphology but the parameters of motility and viability of the nanosilver groups showed a significant decline compared to the control group (P &lt; 0.05). Assessment of sperm DNA fragmentation by the TUNEL assay showed that the nanosilver groups had significantly higher DNA fragmentation and the real-time PCR results also confirmed this. Expression of autophagic and apoptotic markers indicates activation of the apoptosis pathway compared to the autophagy pathway. The expression of LC3 and Beclin-1 (markers that initiate and continue the autophagy) was reduced compared to the sham and control groups. Also, examination of apoptotic pathway genes showed a decrease in Bcl-2 expression and an increase in Bax and caspase-3 expression.

Limitations, reasons for caution
This study requires further research, including protein expression in these two pathways.

Wider implications of the findings
This study investigated the acute (14 days) and chronic (35 days) effects of silver nanorod on reproductive toxicity, which can lead to significant changes in sperm quality. This reduction in quality was observed mainly in the chronic phase and severely affected sperm motility.

Trial registration number
Not Applicable