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

Abstract

This study aimed to evaluate the effects of an intratesticular injection of silver nanoparticles (AgNPs) on reproductive parameters and health of rats, and to evaluate the AgNPs biodistribution in order to develop a nanotechnological contraceptive agent for male animals. Treated animals received 220 lL of AgNPs solution (0.46 mg-Ag/ml) in each testicle and were euthanized: seven, 14, 28, and 56 days after injection. A significant decrease (p < 0.05) in the percentage of motile sperm in D7 (8.8%) was observed, comparing to the control (73.3%), D14 (86.0%), D28 (68.2%), and D56 (90.0%) groups. D7 group also presented a decrease (p < 0.05) in the percentage of normal spermatozoa. Additionally, D7 group showed an increase (p < 0.05) in abnormal midpiece and sperm head morphology compared to the Control group. Seminiferous tubules presented all germline cell types and spermatozoa for all groups. However, D7 group did not present spermatozoa in the epididymis, whereas some spermatozoa and cellular debris were visible in D14 and D28 groups. All animals presented hematological parameters, creatinine, and alanine aminotransferase values within the normal limits for Wistar rats. The percentage of silver found in the liver was always higher than in the other organs analyzed. A pioneering mathematical model is proposed, from which the half-life time of silver in the liver (17 days), spleen (23 days), lungs (30 days), and kidneys (35 days) was extracted. In conclusion, some acute and severe toxic effects were observed in sperm cells following intratesticular injection of AgNPs, although these effects were reversible. No adverse effects to general animal health were observed.

Cytotoxicity of Metal‐Based Nanoparticles: From Mechanisms and Methods of Evaluation to Pathological Manifestations

“…Researchers have found that gavage, intravenous injection, and subcutaneous or intratesticular injection of metal-based NPs resulted in distinct toxic effects on the reproductive system of male animals. [223][224][225] These reproductive toxicity effects include an increase in the sperm deformity rate and a decrease in testicular weight, sperm concentration, testicular histopathology, testosterone levels, and marker enzyme activity. For example, NiO NPs are widely used in electronic devices owing to their versatility; however, they can cause reproductive toxicity in male rats, resulting in moderate to severe toxicity in the testis, epididymis, vas deferens, seminal vesicles, and prostate (Figure 10a).…”

New Prospects in Neutering Male Animals Using Magnetic Nanoparticle Hyperthermia

“…The aforementioned treatments caused the destruction of testicular tissue, decreased testosterone plasma levels in mice within 14 days, and no recovery of reproductive functions until two months after the procedure. More recently, a single intratesticular injection of silver nanoparticles showed acute, but reversible, effects on spermatogenesis in rats [ 6 ]. All of these treatments showed no side effects on animal health over a short duration.…”

“…Most studies focused on improving the efficacy and precision of diagnostics and treatments for reproductive cancers and non-cancer conditions, while others investigated the use of nanomaterials as instruments in assisted reproduction and reproductive biology (see in [ 1 ] for a review). More recently, nanotechnology has been explored as a tool to develop male contraceptive methods [ 2 , 3 , 4 , 5 , 6 ], especially for animals.…”

The Effects of Metal Nanoparticles on the Mammalian Reproductive System

“…The effect of intratesticular injection of Ag NPs (220 μL of Ag NPs solution (0.46 mg Ag/mL) per testis) on rat reproductive parameters was investigated (7,14,28, and 56 days after injection). The results showed a significant decrease in the sperm motility on day 7 (8.8%) compared to the control groups (73.3%), day 14 (86.0%), day 28 (68.2%) and day 56 (90.0%).…”

“…On the other hand, no sperm was observed in the epididymis on day 7, while on days 14 and 28, some sperms were observed. Therefore, intratesticular injection of Ag NPs resulted in severe but reversible effects on the sperm cells [14].…”