Silver nanoparticles effects on epididymal sperm in rats

In Vivo Pro-Inflammatory Effects of Silver Nanoparticles on the Colon Depend on Time and Route of Exposure

Nanosilver is a popular nanomaterial, the potential influence of which on humans is of serious concern. Herein, we exposed male Wistar rats to two regimens: a repeated oral dose of 30 mg/kg bw silver nanoparticles (AgNPs) over 28 days and a single-dose injection of 5 mg/kg bw of AgNPs. At three different time points, we assessed antioxidant defense, oxidative stress and inflammatory parameters in the colon, as well as toxicity markers in the liver and plasma. Both experimental scenarios showed increased oxidative stress and inflammation in the colon. Oral administration seemed to be linked to increased reactive oxygen species generation and lipid peroxidation, while the effects induced by the intravenous exposure were probably mediated by silver ions released from the AgNPs. Repeated oral exposure had a more detrimental effect than the single-dose injection. In conclusion, both administration routes had a similar impact on the colon, although the underlying mechanisms are likely different.

Effects of intratesticular injection of hypertonic mannitol and saline on the quality of donkey sperm, indicators of oxidative stress and testicular tissue pathology

OBJECTIVES

The aim of the present study was to examine donkey sperm quality after intratesticular injection of hypertonic mannitol (HM) and saline (HS).

METHODS

Randomly assigned to five treatment groups were 15 adult male donkeys: (1) Control group (no treatment), (2) Surgery group (surgical castration for testosterone control), (3) NS group (normal saline intratesticular injection), (4) HS group (hypertonic saline), and (5) HM group. We injected 20 mL per testicle. We took 5 mL blood from all donkeys before injection. Castration was performed under general anesthesia 60 days later. Samples included blood and testicular tissue. Total motility (TM), progressive motility (PM), movementy features, DNA damage, morphology, viability, and plasma membrane functionality were evaluated. Hormone analyses, histomorphometric studies and oxidative stress indices including total antioxidant capacity (TAC), glutathione peroxidase (GPx), glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and NADP+/NADPH were evaluated. Apoptosis, pyroptosis-related Bax, Caspase-1, GSDMD, and Bcl-2 expression were also assessed.

RESULTS

In HS and HM groups, testosterone, epididymal sperm count, motility, viability, and plasma membrane functionality dropped while sperm DNA damage increased. HS and HM groups had significantly lower histomorphometric parameters, TAC, GPx, SOD, GSH, and Bcl-2 gene expression. MDA, NADP+/NADPH, Bax, Caspase-1, and GSDMD gene expression were substantially higher in the HS and HM groups than in the control group.

CONCLUSIONS

Toxic effects of hypertonic saline and mannitol on reproductive parameters were seen following, hence, they might be considered as a good chemical sterilizing treatment in donkeys.

Exogenous taurine administration abates reproductive dysfunction in male rats exposed to silver nanoparticles

The broad contemporary applications of silver nanoparticles (AgNPs) have been associated with various toxicities including reproductive toxicity. Taurine is well acknowledged for its potent pharmacological role in numerous disease models and chemically-mediated toxicity. We investigated the effect of taurine on AgNPs-induced reproductive toxicity in male rats. The animals were intraperitoneally injected with AgNPs (200 μg/kg) alone or co-administered with taurine at 50 and 100 mg/kg for 21 successive days. Exogenous taurine administration significantly abated AgNPs-induced oxidative injury by decreasing the levels of oxidative stress indices while boosting antioxidant enzymes activities and glutathione level in the hypothalamus, testes and epididymis of exposed animals. Taurine administration alleviated AgNPs-induced inflammatory response and caspase-3 activity, an apoptotic biomarker. Moreover, taurine significantly improved spermiogram, reproductive hormones and the marker enzymes of testicular function in AgNPs-treated animals. The ameliorative effect of taurine on pathological lesions induced by AgNPs in the exposed animals was substantiated by histopathological data. This study provides the first mechanistic evidence that taurine supplementation affords therapeutic effect against reproductive dysfunction associated with AgNPs exposure in male rats.

Does Nanosilver Exposure Modulate Steroid Metabolism in the Testes?-A Possible Role of Redox Balance Disruption

Silver nanoparticles (AgNPs) are a popular engineered nanomaterial widely used in industry. Despite the benefits they bring to society, AgNPs are not neutral to human health. The aim of this study was to evaluate the effects of a single intravenous dose (5 mg/kg body weight) of 20 nm AgNPs on steroid metabolism and redox balance in the testes of adult rats. The effects were evaluated 1 day or 28 days after intervention and compared with saline-treated animals. Decreased aromatase and estrogen receptor α levels (by 21% and 27%, respectively) were observed 1 day after AgNPs administration, while increased testosterone, increased dihydrotestosterone levels, higher androgen receptors and higher aromatase expression in Leydig cells (by 43%, 50%, 20% and 32%, respectively) as well as lower (by 35%) androgen receptor protein levels were observed 28 days after exposure to AgNPs compared to control groups. The AgNPs treatment resulted in decreased superoxide dismutase activity, decreased GSH/GSSG ratio, and increased glutathione reductase activity (by 23%, 63% and 28%, respectively) compared to control animals, irrespective of the time of measurement. Increased (by 28%) intratesticular lipid hydroperoxides level was observed 1 day after AgNPs exposure, while decreased (by 70%) GSH and increased (by 43%) 7-ketocholesterol levels were observed 28 days after treatment compared to control animals. Conclusions: AgNPs exposure caused redox imbalance in the gonads shortly after AgNPs administration, while a longer perspective AgNPs exposure was associated with impaired androgen metabolism, probably due to increased oxidative stress.

Synthesis and in vivo evaluation of three fluid spray dried hybrid ciprofloxacin microparticles in Sprague Dawley rats

The aim of this study is to prepare and characterise mucoadhesive silica-coated silver nanoparticles loaded with ciprofloxacin (S-AgNPs-CSCFX), and investigate serum biochemical, haematological, and histopathological effects in Sprague Dawley rats upon oral administration. S-AgNPs-CSCFX microparticles were prepared using three fluid nozzle spray drying and characterised by scanning electron microscopy (SEM), X-ray dispersive spectrometry (EDX), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), zeta potential and particles size measurements and X-ray powder diffraction (XRPD). Adult male Sprague Dawley rats were randomly divided between six-treated groups, including blank S-AgNPs and S-AgNPs-CSCFX (LD: Low dose; MD: Median Dose; HD: High Dose) and control group. Each group was treated daily to evaluate the effect of the prepared particles on the lipid profile, serum biochemical, hormonal level, haemogram, and vital organ histopathology. The results showed successful encapsulation of silver nanoparticles which resulted in spherical-shaped S-AgNPs-CSCFX with an average size of 1-5 μm and surface charge of 25.2 ± 5.52 mv. The in-vivo results showed that different doses of blank S-AgNPs and S-AgNPs-CSCFX had no significant toxic effects on the physiological, biochemical, and haematological parameters. There were no marked histopathological alterations in the vital organs of the treated rats with blank and loaded particles.

Silver contamination and its toxicity and risk management in terrestrial and aquatic ecosystems

Silver (Ag), a naturally occurring, rare and precious metal, is found in major minerals such as cerargyrite (AgCl), pyrargyrite (Ag₃SbS₃), proustite (Ag₃AsS₃), and stephanite (Ag₅SbS₄). From these minerals, Ag is released into soil and water through the weathering of rocks and mining activities. Silver also enters the environment by manufacturing and using Ag compounds in electroplating and photography, catalysts, medical devices, and batteries. With >400 t of Ag NPs produced yearly, Ag NPs have become a rapidly growing source of anthropogenic Ag input in the environment. In soils and natural waters, most Ag is sorbed to soil particles and sediments and precipitated as oxides, carbonates, sulphides, chlorides and hydroxides. Silver and its compounds are toxic, and humans and other animals are exposed to Ag through inhalation of air and the consumption of Ag-contaminated food and drinking water. Remediation of Ag-contaminated soil and water sources can be achieved through immobilization and mobilization processes. Immobilization of Ag in soil and groundwater reduces the bioavailability and mobility of Ag, while mobilization of Ag in the soil can facilitate its removal. This review provides an overview of the current understanding of the sources, geochemistry, health hazards, remediation practices and regulatory mandates of Ag contamination in complex environmental settings, including soil and aquatic ecosystems. Knowledge gaps and future research priorities in the sustainable management of Ag contamination in these settings are also discussed.

Ameliorative role of chitosan nanoparticles against silver nanoparticle-induced reproductive toxicity in male albino rats

This study was designed to evaluate the protective potentials of chitosan nanoparticles (ChNPs) against silver nanoparticle (AgNP)-induced reproductive toxicity in male Wister albino rats. AgNPs, ChNPs, and AgNPs particles coated with ChNPs were characterized by using transmission electron microscope. Control rats were injected interperitoneally with 0.5% aqueous carboxymethyl cellulose. Second group was given ChNPs at a dose 300 mg/kg bwt. Third group was given AgNPs at a dose 50 mg/kg bwt. Fourth group was given AgNPs with chitosan nanoparticles simultaneously. Fifth group was given silver nanoparticles coated with chitosan nanoparticles at a dose 300 mg/kg bwt. TEM showed the formation of AgNPs with average size of 42.7 nm, ChNPs with average size of 33.3 nm, and AgNPs coated with ChNPs with average size of 48.1 nm. AgNPs significantly reduced serum levels of FSH, LH, testosterone and prolactin, sperm count, morphology index, vitality, total motility and progressive motility, the activities of catalase and superoxide dismutase, and the concentration of reduced glutathione in testicular tissues. However, it significantly increased malondialdehyde concentration in testicular tissues, sperm abnormalities, testicular tissue damages, non-progressive motility, and immotile sperms. On the contrast, ChNPs ameliorated AgNP-induced alteration in serum levels of sex hormones, spermogram, and testicular tissue's structure and functions. These results indicated that ChNPs had protective potential against AgNP-induced reproductive toxicity and ChNPs coating AgNPs had more potent protective effect than ChNPs administrated together with AgNPs.

Effects of Au@Ag core-shell nanostructure with alginate coating on male reproductive system in mice

Despite the widespread use of silver nanoparticles (NPs), these NPs can accumulate and have toxic effects on various organs. However, the effects of silver nanostructures (Ag-NS) with alginate coating on the male reproductive system have not been studied. Therefore, this study aimed to investigate the impacts of this NS on sperm function and testicular structure. After the synthesis and characterization of Ag-NS, the animals were divided into five groups (n = 8), including one control group, two sham groups (received 1.5 mg/kg/day alginate solution for 14 and 35 days), and two treatment groups (received Ag-NS at the same dose and time). Following injections, sperm parameters, apoptosis, and autophagy were analyzed by the TUNEL assay and measurement of the mRNA expression of Bax, Bcl-2, caspase-3, LC3, and Beclin-1. Fertilization rate was assessed by in vitro fertilization (IVF), and testicular structure was analyzed using the TUNEL assay and hematoxylin and eosin (H&E) staining. The results showed that the NS was rod-shaped, had a size of about 60 nm, and could reduce sperm function and fertility. Gene expression results demonstrated an increase in the apoptotic markers and a decrease in autophagy markers, indicating apoptotic cell death. Moreover, Ag-NS invaded testicular tissues, especially in the chronic phase (35 days), resulting in tissue alteration and epithelium disintegration. The results suggest that sperm parameters and fertility were affected. In addition, NS has negative influences on testicular tissues, causing infertility in men exposed to these NS.

Putative adverse outcome pathways for silver nanoparticle toxicity on mammalian male reproductive system: a literature review

BACKGROUND

Adverse outcome pathways (AOPs) are conceptual frameworks that organize knowledge about biological interactions and toxicity mechanisms. They present a sequence of events commencing with initial interaction(s) of a stressor, which defines the perturbation in a biological system (molecular initiating event, MIE), and a dependent series of key events (KEs), ending with an adverse outcome (AO). AOPs have recently become the subject of intense studies in a view to better understand the mechanisms of nanomaterial (NM) toxicity. Silver nanoparticles (Ag NPs) are one of the most explored nanostructures and are extensively used in various application. This, in turn, has increased the potential for interactions of Ag NPs with environments, and toxicity to human health. The aim of this study was to construct a putative AOPs (pAOP) related to reproductive toxicity of Ag NPs, in order to lay the groundwork for a better comprehension of mechanisms affecting both undesired toxicity (against human cell) and expected toxicity (against microorganisms).

METHODS

PubMed and Scopus were systematically searched for peer-reviewed studies examining reproductive toxicity potential of Ag NPs. The quality of selected studies was assessed through ToxRTool. Eventually, forty-eight studies published between 2005 and 2022 were selected to identify the mechanisms of Ag NPs impact on reproductive function in human male. The biological endpoints, measurements, and results were extracted from these studies. Where possible, endpoints were assigned to a potential KE and an AO using expert judgment. Then, KEs were classified at each major level of biological organization.

RESULTS

We identified the impairment of intracellular SH-containing biomolecules, which are major cellular antioxidants, as a putative MIE, with subsequent KEs defined as ROS accumulation, mitochondrial damage, DNA damage and lipid peroxidation, apoptosis, reduced production of reproductive hormones and reduced quality of sperm. These successive KEs may result in impaired male fertility (AO).

CONCLUSION

This research recapitulates and schematically represents complex literature data gathered from different biological levels and propose a pAOP related to the reproductive toxicity induced by AgNPs. The development of AOPs specific to NMs should be encouraged in order to provide new insights to gain a better understanding of NP toxicity.

Impact of Nanoparticles on Male Fertility: What Do We Really Know? A Systematic Review

The real impact of nanoparticles on male fertility is evaluated after a careful analysis of the available literature. The first part reviews animal models to understand the testicular biodistribution and biopersistence of nanoparticles, while the second part evaluates their in vitro and in vivo biotoxicity. Our main findings suggest that nanoparticles are generally able to reach the testicle in small quantities where they persist for several months, regardless of the route of exposure. However, there is not enough evidence that they can cross the blood-testis barrier. Of note, the majority of nanoparticles have low direct toxicity to the testis, but there are indications that some might act as endocrine disruptors. Overall, the impact on spermatogenesis in adults is generally weak and reversible, but exceptions exist and merit increased attention. Finally, we comment on several methodological or analytical biases which have led some studies to exaggerate the reprotoxicity of nanoparticles. In the future, rigorous clinical studies in tandem with mechanistic studies are needed to elucidate the real risk posed by nanoparticles on male fertility.

Impact of chitosan administration on titanium dioxide nanoparticles induced testicular dysfunction

The potential reproductive toxic effects of oral TiO₂ NPs in adult male rats as well as the possible alleviation of chitosan administration was investigated. Animals were allocated to four groups; the first group received deionized water and was assigned as a control group. In the second group, rats received chitosan at a dose of 5 mg/kg BW/day. The third group was designed for administration of TiO₂ NPs at a dose of 150 mg/kg BW/day (1/80 LD₅₀). Rats in the fourth group received both TiO₂ NPs and chitosan. After 14 days, TiO₂ NPs induced testicular lipid peroxidation as well as oxidative stress. Nano-titanium significantly upregulated genes that encode apoptosis and inflammation in testicular tissue. Moreover, it induced histological alteration in the testicular structure with impairment in spermatogenesis via reduction of PCNA immune-staining. Chitosan administration significantly improved the activities of testicular GPx, SOD, and CAT enzymes. In addition, it significantly down-regulated the relative expressions of pro-apoptotic and pro-inflammatory testicular genes. Chitosan was able to improve the testicular architecture as well as spermatogenesis. The current study revealed the capability of chitosan to ameliorate nano-titanium induced testicular toxicity. Thus, attention should be given to the extensive consumption of nano-titanium particles.

Beneficial effects of Spirulina platensis on mice testis damaged by silver nanoparticles

Silver nanoparticles (AgNPs) have been used widely in medical applications and various industries. Humans could be exposed to the risk of AgNPs toxicity through different routes. The current study aimed to investigate the role of Spirulina platensis (SP) against the side effects of AgNPs on mice testis. Adult male NMRI mice were divided into four groups: control group, SP group (300 mg/kg bwt), AgNPs (20 nm) group (500 mg/kg bwt), Co-treated group (SP + AgNPs). The groups were treated orally for 35 days. Subsequently, epididymal sperm parameters, sperm DNA integrity, daily sperm production (DSP), sexual hormones level, malondialdehyde (MDA), total antioxidant capacity (TAC) and spermatogenesis indices were measured. In addition, the histopathology of testes was evaluated using tissue processing, haematoxylin-eosin staining and stereology techniques. A significant decrease in the number of spermatogenic cells, Leydig cells and sperm parameters was observed in the AgNPs treated group. Serum levels of testosterone and TAC were decreased significantly following AgNPs treatment. Also, MDA incremented in the serum of AgNPs treated mice. The stereological analysis revealed that AgNPs exposure induced histopathological changes in the seminiferous tubules, degeneration and dissociation of spermatogenic cells. In contrast, SP co-administration significantly counteracted AgNPs reproductive toxicity impacts. SP co-exposure caused an increase in spermatogenesis indices, TAC and also a decrease in MDA. SP improved the histopathological changes of testes tissue and spermatozoa abnormalities. In parallel, SP modulated levels of testosterone, FSH and LH. Spirulina platensis exhibited the protective potential by regulating oxidative stress against AgNPs-induced reproductive toxicity. SP could be a candidate therapy against AgNPs reprotoxic impacts.

Assessment of the potential toxic effect of magnetite nanoparticles on the male reproductive system based on immunological and molecular studies

Magnetite nanoparticles (MNPs) are the most conventional type of iron oxide nanoparticles used in the food industrial processes, removal of heavy metals, and biomedical applications in vivo or in vitro. Until now, there is no sufficient information that can confirm its effect on the body's immune system and reproductive health in males. The purpose of this research is to estimate the immunotoxic and reproductive toxic effects of MNPs in male rats. This study included 36 adult male albino rats divided into three groups. The experimental groups were intraperitoneally injected with MNPs at doses of 5 and 10 mg/kg body weight 3 times/week for 60 days, while the control group was injected with saline solution. MNPs caused a significant decrease in the body weight change of the high-treated group. MNPs produced changes in the lymphocyte proliferation rate which referred to a significant immunotoxic effect measured by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-di-phenyltetrazolium bromide reduction method. The testicular tissue of male-treated rats showed some moderate and severe degenerative changes. The sperm parameters of count, motility, and viability were significantly decreased. Sperm morphological abnormalities were detected in all treated animals. MNPs produced a significant decrease in testosterone levels, increased the level of malondialdehyde, impaired the activity of the antioxidant enzymes and induced testicular DNA damage. In conclusion, MNPs affected the normal immune state in male rats and facilitated the generation of reactive oxygen species subsequently triggering testicular oxidative stress damages. All these consequences had a negative impact on male reproductive health.

An Overview of Essential Microelements and Common Metallic Nanoparticles and Their Effects on Male Fertility

Numerous factors affect reproduction, including stress, diet, obesity, the use of stimulants, or exposure to toxins, along with heavy elements (lead, silver, cadmium, uranium, vanadium, mercury, arsenic). Metals, like other xenotoxins, can cause infertility through, e.g., impairment of endocrine function and gametogenesis or excess production of reactive oxygen species (ROS). The advancement of nanotechnology has created another hazard to human safety through exposure to metals in the form of nanomaterials (NMs). Nanoparticles (NPs) exhibit a specific ability to penetrate cell membranes and biological barriers in the human body. These ultra-fine particles (<100 nm) can enter the human body through the respiratory tract, food, skin, injection, or implantation. Once absorbed, NPs are transported to various organs through the blood or lymph. Absorbed NPs, thanks to ultrahigh reactivity compared to bulk materials in microscale size, disrupt the homeostasis of the body as a result of interaction with biological molecules such as DNA, lipids, and proteins; interfering with the functioning of cells, organs, and physiological systems; and leading to severe pathological dysfunctions. Over the past decades, much research has been performed on the reproductive effects of essential trace elements. The research hypothesis that disturbances in the metabolism of trace elements are one of the many causes of infertility has been unquestionably confirmed. This review examines the complex reproductive risks for men regarding the exposure to potentially harmless xenobiotics based on a series of 298 articles over the past 30 years. The research was conducted using PubMed, Web of Science, and Scopus databases searching for papers devoted to in vivo and in vitro studies related to the influence of essential elements (iron, selenium, manganese, cobalt, zinc, copper, and molybdenum) and widely used metallic NPs on male reproduction potential.

Effects of Selected Metal Nanoparticles (Ag, ZnO, TiO2) on the Structure and Function of Reproductive Organs

Various studies have shown that the reproductive organs are highly sensitive to toxic elements found in the environment. Due to technological progress, the use of nanoparticles has become more common nowadays. Nanoparticles are used for drug delivery because their dimensions allow them to circulate throughout the body and enter directly into the cell. Antimicrobial properties are increasingly used in the manufacture of medical devices, textiles, food packaging, cosmetics, and other consumer products. Nanoparticles provide several benefits, but aspects related to their effects on living organisms and the environment are not well known. This review summarizes current in vivo, and in vitro animal studies focused on the evaluation of toxicity of selected metal nanoparticles (Ag, ZnO, TiO₂) on male and female reproductive health. It can be concluded that higher concentrations of metal nanoparticles in the male reproductive system can cause a decrease in spermatozoa motility, viability and disruption of membrane integrity. Histopathological changes of the testicular epithelium, infiltration of inflammatory cells in the epididymis, and prostatic hyperplasia have been observed. Nanoparticles in the female reproductive system caused their accumulation in the ovaries and uterus. Metal nanoparticles most likely induce polycystic ovary syndrome and follicular atresia, inflammation, apoptosis, and necrosis also occurred.

Influence of copper treatment on bioaccumulation, survival, behavior, and fecundity in the fruit fly Drosophila melanogaster: Toxicity of copper oxide nanoparticles differ from dissolved copper

Copper oxide (CuO) NPs are widely used and subsequently released into terrestrial ecosystems. In the present study, bioaccumulation and effects of CuO NPs and dissolved Cu was examined in the fruit fly Drosophila melanogaster after 7 and 10 days dietary exposure at concentrations ranging between 0.09 and 1.2 mg Cu ml^-1 for dissolved Cu and between 0.2 and 11 mg Cu ml^-1 for CuO NPs. Both Cu forms were bioaccumulated and affected survival and climbing in flies, but not egg-to-adult development. Dissolved Cu caused higher mortality than CuO NPs (CuO NPs 10-days LC₅₀ was 2 times higher), whereas NPs affected climbing and decreased the number of eggs laid per female, potentially affecting fruit fly population size in terrestrial environments. Thus, the study indicates that CuO NPs might cause effects that are different from dissolved Cu due to differences in the mechanism of uptake or toxicity. Therefore, we need to consider relevant sublethal endpoints when assessing these CuO NPs to ensure that we do not overlook long-term effects.

Particle Safety Assessment in Additive Manufacturing: From Exposure Risks to Advanced Toxicology Testing

Additive manufacturing (AM) or industrial three-dimensional (3D) printing drives a new spectrum of design and production possibilities; pushing the boundaries both in the application by production of sophisticated products as well as the development of next-generation materials. AM technologies apply a diversity of feedstocks, including plastic, metallic, and ceramic particle powders with distinct size, shape, and surface chemistry. In addition, powders are often reused, which may change the particles' physicochemical properties and by that alter their toxic potential. The AM production technology commonly relies on a laser or electron beam to selectively melt or sinter particle powders. Large energy input on feedstock powders generates several byproducts, including varying amounts of virgin microparticles, nanoparticles, spatter, and volatile chemicals that are emitted in the working environment; throughout the production and processing phases. The micro and nanoscale size may enable particles to interact with and to cross biological barriers, which could, in turn, give rise to unexpected adverse outcomes, including inflammation, oxidative stress, activation of signaling pathways, genotoxicity, and carcinogenicity. Another important aspect of AM-associated risks is emission/leakage of mono- and oligomers due to polymer breakdown and high temperature transformation of chemicals from polymeric particles, both during production, use, and in vivo, including in target cells. These chemicals are potential inducers of direct toxicity, genotoxicity, and endocrine disruption. Nevertheless, understanding whether AM particle powders and their byproducts may exert adverse effects in humans is largely lacking and urges comprehensive safety assessment across the entire AM lifecycle-spanning from virgin and reused to airborne particles. Therefore, this review will detail: 1) brief overview of the AM feedstock powders, impact of reuse on particle physicochemical properties, main exposure pathways and protective measures in AM industry, 2) role of particle biological identity and key toxicological endpoints in the particle safety assessment, and 3) next-generation toxicology approaches in nanosafety for safety assessment in AM. Altogether, the proposed testing approach will enable a deeper understanding of existing and emerging particle and chemical safety challenges and provide a strategy for the development of cutting-edge methodologies for hazard identification and risk assessment in the AM industry.

Effect of Titanium Dioxide and Silver Nanoparticles on Mitochondrial Dynamics in Mouse Testis Tissue

This study was performed to investigate whether the toxicity of nanoparticles (Ag NPs or TiO₂ NPs) affected mitochondrial dynamics (mitochondrial fusion and fission mechanisms) in testicular cells of mice. Animals were assigned into three groups (ten mice per group): control group (distilled water), TiO₂ NP group (5 mg/kg per dose), and Ag NP group (5 mg/kg per dose). NPs were administered intravenously (via tail vein) to mice with 3-day intervals. To determine the possible toxic effect of NPs on mitochondrial dynamics, the expression levels of mitochondrial fission (Drp1)- and fusion (Mfn1, Mfn2, OPA1)-related genes were analyzed. The results showed that both Ag NPs and TiO₂ NPs entered the testis via the blood-testis barier and accumulated in mouse testis tissue. Experiments showed that administration of Ag NPs neither alters testicular weight and testicular index nor causes significant toxic effect on sperm parameters. RT-PCR analysis demonstrated that Ag NP treatment did not disrupt mitochondrial dynamics in testicular cells. Conversely, administration of TiO₂ NPs (anatase, < 25 nm) decreased the sperm motility and the percentages of sperms with swollen tail. Furthermore, RT-PCR and western blot analyses showed that TiO₂ NPs disrupted mitochondrial dynamics by causing excess mitochondrial fission (excess expression of Drp1 gene and DRP1 protein). This is the first report on the toxicity of nanoparticles on mitochondrial dynamics (fusion and fission mechanisms) in testicular cells.

Time-delayed effects of a single application of AgNPs on structure of testes and functions in Blaps polychresta Forskal, 1775 (Coleoptera: Tenebrionidae)

Silver nanoparticles (AgNPs) are currently the most frequently used engineered nanoparticles. The penetration of AgNPs into ecosystems is undeniable, and their adverse effects on organism reproduction are of fundamental importance for ecosystem stability. In this study, the survival time of the Egyptian beetle Blaps polychresta Forskal, 1775 (Coleoptera: Tenebrionidae), after a single application of 7 different doses, was calculated for 30 days. Then, for the group for which the effect on mortality was calculated as LOAEL - the Lowest Observed Adverse Effect Level, namely, 0.03 mg AgNPs/g body weight (b.w.t.), the following were assessed: structure and ultrastructure of gonads by TEM and SEM, cell viability by cytometry, DNA damage by the comet assay, and a variety of stress markers by spectrophotometric methods. A dose-dependent reduction in the survival time of the insects was revealed. Detailed analysis of the testes of beetles treated with 0.03 mg AgNPs/g b.w.t. revealed numerous adverse effects of nanoparticles in structure and ultrastructure, accompanied by increased apoptosis (but not necrosis), increased DNA damage, increased lipid peroxidation, and decreased levels of antioxidant enzymes. Most likely, the observed results are connected with the gradual release of Ag⁺ from the surface of the nanoparticles, which, once applied, are internalized in cells and become a long-lasting, stable source of Ag⁺ ions. Thus, a single exposure to AgNPs may have the effects of chronic exposure and lead to structural damage and dysfunction of the gonads of B. polychresta.

Attributes of oxidative stress in the reproductive toxicity of nickel oxide nanoparticles in male rats

The nanoparticles of nickel are now being widely used in industrial, commercial, and biomedical applications. In recent years, health safety issues posed by them have aroused concerns among health scientists. The aim of the present study was to investigate the role of oxidative stress in male reproductive toxicity induced by nickel oxide nanoparticles in rats. Male Wistar rats (140-170 g) were administered with nickel oxide nanoparticles (NiONPs) (particles size <30 nm) (5 mg/kg body weight) by gavage for 30 days. Its effects on different parameters, viz., sperm count, motility, and morphology, were investigated. DNA damage in sperms was monitored through comet assay. All these observations indicated a spermicidal effect of NiONPs. Results on lipid peroxidation (MDA, H₂O₂, and NO) and oxidative stress (GSH, GPx, and catalase) thus studied in testes exhibited adverse effects of NiONPs. Histopathological results on male reproductive organs, viz., testis, epididymis, vas deferens, seminal vesicles, and prostate also demonstrated moderate to severe toxicity. A comparison of these results with those obtained on nickel oxide microparticle (NiOMP)-treated rats showed that NiONPs are more toxic than NiOMPs. Furthermore, NiONPs could create an imbalance between oxidants and antioxidants in the testes. It is concluded that redox imbalance in testes constitutes a major mechanism of NiONP-induced reproductive toxicity.

Genotoxicity of physical silver nanoparticles, produced by the HVAD method, for Chinchilla lanigera genome

Each year, growing demand for silver nanoparticles (AgNP) contributes to the search for alternative methods of their production. Stable AgNP with antibacterial properties, low toxicity to the environment and living organisms are especially valued. In the study presented here, an attempt was made to assess the toxicity of two AgNP solutions produced using the HVAD method to the Chinchilla lanigera genome. The AgNO₃ solution was the indicator and reference for the harmfulness of AgNP. The study was carried out in vitro on bone marrow cells isolated from Chinchilla lanigera bones. The genotoxicity was assessed by comet assay, following the treatment of cells with three silver solutions: unstable and sodium citrate-stabilized silver nanoparticles, as well as silver nitrate at three concentrations (5, 10 and 20 µg/L), after 3, 6 and 24 h. Based on the percentage of the DNA content in the comet tail and the tail moment, an increase in cell DNA integrity disruption was demonstrated in all tested variants: of solution, exposure time and concentration, compared to the control sample. A statistically significant correlation was determined between the level of induced DNA breaks and the concentration of the active solutions and the duration of their activity. A solution of silver nanoparticles stabilized with sodium citrate was shown to have the most harmful effect on bone marrow cells. Silver nitrate demonstrated a level of toxicity similar to these particles. Further studies are necessary to directly compare the genotoxic properties of AgNP produced using the HVAD method and the chemical method under the same conditions.

Metal Oxide Nanoparticles: Evidence of Adverse Effects on the Male Reproductive System

Metal oxide nanoparticles (MONPs) are inorganic materials that have become a valuable tool for many industrial sectors, especially in healthcare, due to their versatility, unique intrinsic properties, and relatively inexpensive production cost. As a consequence of their wide applications, human exposure to MONPs has increased dramatically. More recently, their use has become somehow controversial. On one hand, MONPs can interact with cellular macromolecules, which makes them useful platforms for diagnostic and therapeutic interventions. On the other hand, research suggests that these MONPs can cross the blood–testis barrier and accumulate in the testis. Although it has been demonstrated that some MONPs have protective effects on male germ cells, contradictory reports suggest that these nanoparticles compromise male fertility by interfering with spermatogenesis. In fact, in vitro and in vivo studies indicate that exposure to MONPs could induce the overproduction of reactive oxygen species, resulting in oxidative stress, which is the main suggested molecular mechanism that leads to germ cells’ toxicity. The latter results in subsequent damage to proteins, cell membranes, and DNA, which ultimately may lead to the impairment of the male reproductive system. The present manuscript overviews the therapeutic potential of MONPs and their biomedical applications, followed by a critical view of their potential risks in mammalian male fertility, as suggested by recent scientific literature.

Effects of quetiapine administration on sperm quality and testicular histology

Quetiapine is one of the most commonly prescribed antipsychotics to treat schizophrenia in adults, in particular. In this study, quetiapine's effects were assessed on healthy sperm production in rats at repeated-pharmacological doses. Additionally, the effects of quetiapine on oxidative status and hormonal balance were also evaluated in rats. Quetiapine was administered to rats orally at 10, 20, and 40 mg/kg body weight doses for 28 days. At the end of this period, body and organ weights were measured, sperm concentration, motility, and morphology were determined, sperm damage was assessed, and histopathological analysis of testicular tissue was performed. Additionally, serum FSH, LH, and testosterone levels as male reproductive hormones were measured. Catalase, superoxide dismutase, glutathione, and malondialdehyde levels were determined for evaluating the oxidative status of testicular tissue. The findings obtained in this study showed that relative epididymis weights and sperm concentration decreased and abnormal sperm morphology increased in quetiapine-administered rats. Irregularity of typical architecture of the seminiferous tubules and germinal cell disorganization was observed in testicular sections of 20 and 40 mg/kg quetiapine-administered rats. Further, serum LH and testosterone levels decreased in 20 and 40 mg/kg quetiapine-administered rats. Additionally, decreased catalase and superoxide dismutase activities in testicular tissue of quetiapine-administered rats and increased malondialdehyde levels in testicular tissue of 40 mg/kg quetiapine-administered rats were measured. In conclusion, quetiapine treatment decreased sperm quality, altered hormone levels, and induced oxidative stress may be considered potential contributors to this adverse effect.

Application of the comet assay for the evaluation of DNA damage in mature sperm

DNA integrity is considered an important parameter of semen quality and is of significant value as a predictor of male fertility. Currently, there are several methods that can assess sperm DNA integrity. One such assay is the comet assay, or single-cell gel electrophoresis, which is a simple, sensitive, reliable, quick and low-cost technique that is used for measuring DNA strand breaks and repair at the level of individual cells. Although the comet assay is usually performed with somatic cells from different organs, the assay has the ability to detect genotoxicity in germ cells at different stages of spermatogenesis. Since the ability of sperm to remove DNA damage differs between the stages, interpretation of the results is dependent on the cells used. In this paper we give an overview on the use and applications of the comet assay on mature sperm and its ability to detect sperm DNA damage in both animals and humans. Overall, it can be concluded that the presence in sperm of significantly damaged DNA, assessed by the comet assay, is related to male infertility and seems to reduce live births. Although there is some evidence that sperm DNA damage also has a long-term impact on offspring's health, this aspect of DNA damage in sperm is understudied and deserves further attention. In summary, the comet assay can be applied as a useful tool to study effects of genotoxic exposures on sperm DNA integrity in animals and humans.

Toxicity and deleterious impacts of selenium nanoparticles at supranutritional and imbalance levels on male goldfish (Carassius auratus) sperm

BACKGROUND

Selenium has a major role in male reproduction and antioxidative mechanisms. Although deficiency of this element can result in damages to the body's organs, this metalloid can induce deleterious effects in organisms by causing oxidative stress. This study assessed the spermatotoxicity of selenium nanoparticles (SeNPs) in goldfish (Carassius auratus) based on genotoxicity, antioxidant status, sperm quality, and histopathology.

METHODS

The fish with an average weight of 70 g (n = 288) were divided into four experimental groups (three replicates) and fed three times a day with SeNPs at different levels of 0, 0.1, 0.5, and 1 mg kg diet for 30 and 60 days.

RESULTS

After 30 and 60 days of feeding trial, compared to the control group, spermatocrit percentage markedly decreased at 1 mg kg SeNPs on day 30 as well as at 0.5 and 1 mg kg on day 60 (p < 0.05). Computer-assisted sperm analysis parameters especially VCL, VSL, and VAP decreased in response to SeNPs (p < 0.05). Percentage of fast speed progressive sperm cells was highest in fish fed with 0.1 mg kg SeNPs following the dietary experiment and significantly reduced in a SeNPs dose-dependent manner (p < 0.05). In addition, the levels of Malondialdehyde and Glutathione peroxidase were significantly elevated in seminal plasma of all SeNPs-treated groups (p < 0.05). On day 60, DNA damage of sperm was greatly increased at 1 mg kg SeNPs (p < 0.05). Moreover, the highest percentage of spermatocyte and spermatid were observed at the highest dose of SeNPs while the highest percentage of spermatozoa was recorded at the lowest and moderate SeNPs doses.

CONCLUSION

These findings suggested that non-optimal doses of SeNPs could reduce sperm quality, induce oxidative stress, and DNA damage in sperm, and disrupt testis development.

Alleviation of silver nanoparticle-induced sexual behavior and testicular parameters dysfunction in male mice by yttrium oxide nanoparticles

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Exposure to silver nanoparticles decreased the weight of the reproductive organs, sexual behavior, oxidative defense parameters, sperm count and their motility in male mice.

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In addition, serum testosterone, apoptotic germ cells and testicular histology were also disrupted due to silver nanoparticles.

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Yttrium oxide nanoparticles have protective effects on sexual behavior and spermatotoxicity induced by silver nanoparticles in male mice.

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The toxicity of silver nanoparticles altered testicular functions that were effectively ameliorated by yttrium oxide nanoparticles.

Silver nanoparticles (Ag-NPs) can easily cross through the blood-testis barrier and encourage reproductive dysfunction. This study investigated the protective effects of yttrium oxide nanoparticles (YO-NPs) on sexual behavior and spermatotoxicity induced by Ag-NPs in male mice. Twenty-four male mice were separated into four groups and injected intraperitoneally once a week as the following: group I (Ag-NPs at the dose of 40 mg/kg), group II (YO-NPs at the dose of 40 mg/kg), group III (Ag + YO NPs at the doses of 40 mg/kg, each) and group IV (control; distilled water). After 35 days of the injections, the sexual behavior, oxidative parameters in testis, sperm parameters, serum testosterone, apoptotic germ cells and testicular histology were evaluated. Our findings showed that Ag-NPs decreased the weight of the reproductive organs, sexual behavior, oxidative defense parameters, sperm count and motility of male mice. In addition, the apoptotic cells in testicular cross-sections and TBARS level increased after Ag-NPs exposure when compared to other groups. However, the YO-NPs had protective effects in the studied parameters of testicles and minimized the Ag-NPs toxicity in male mice. In conclusion, the results revealed that the toxicity of Ag-NPS altered testicular functions in male mice that were effectively ameliorated by YO-NPs.

Can nanomaterials induce reproductive toxicity in male mammals? A historical and critical review

The nanotechnology enabled the development of nanomaterials (NMs) with a variety of industrial, biomedical, and consumer applications. However, the mechanism of action (MoA) and toxicity of NMs remain unclear, especially in the male reproductive system. Thus, this study aimed to perform a bibliometric and systematic review of the literature on the toxic effects of different types of NMs on the male reproductive system and function in mammalian models. A series of 236 articles related to the in vitro and in vivo reproductive toxicity of NMs in mammalian models were analyzed. The data concerning the bioaccumulation, experimental conditions (types of NMs, species, cell lines, exposure period, and routes of exposure), and the MoA and toxicity of NMs were summarized and discussed. Results showed that this field of research began in 2005 and has experienced an exponential increase since 2012. Revised data confirmed that the NMs have the ability to cross the blood-testis barrier and bioaccumulate in several organs of the male reproductive system, such as testis, prostate, epididymis, and seminal vesicle. A similar MoA and toxicity were observed after in vitro and in vivo exposure to NMs. The NM reproductive toxicity was mainly related to ROS production, oxidative stress, DNA damage and apoptosis. In conclusion, the NM exposure induces bioaccumulation and toxic effects on male reproductive system of mammal models, confirming its potential risk to human and environmental health. The knowledge concerning the NM reproductive toxicity contributes to safety and sustainable use of nanotechnology.

Toxicity mechanisms of nanoparticles in the male reproductive system

The field of nanotechnology has allowed for increasing nanoparticle (NP) exposure to the male reproductive system. Certain NPs have been reported to have adverse consequences on male germ and somatic cells. Germ cells are the bridge between generations and are responsible for the transmission of genetic and epigenetic information to future generations. A number of NPs have negative impacts on male germ and somatic cells which could ultimately affect fertility or the ability to produce healthy offspring. These impacts are related to NP composition, modification, concentration, agglomeration, and route of administration. NPs can induce severe toxic effects on the male reproduction system after passing through the blood-testis barrier and ultimately damaging the spermatozoa. Therefore, understanding the impacts of NPs on reproduction is necessary. This review will provide a comprehensive overview on the current state of knowledge derived from the previous in vivo and in vitro research on effects of NPs on the male reproductive system at the genetic, cellular, and molecular levels.

Toxic and Microbiological Effects of Iron Oxide and Silver Nanoparticles as Additives on Extended Ram Semen

The aim of the study was to investigate the effect of iron oxide (Fe) and silver (Ag) nanoparticles (NPs) on ram semen. A skim milk extender without antibiotics was used as a diluent of 21 ejaculates (8 rams; 2-3 ejaculates/ram). The groups of control (C; semen without NPs), Fe NPs (3.072 mg Fe₃O₄/mL semen), and Ag NPs (2.048 mg Ag-Fe/mL semen) were incubated (15 °C; 30 min), and then a magnetic field was used for NPs' removal. Standard microbiological procedures were performed for all groups. Post-treated samples were stored (15 °C) for 24 h, and sperm variables (kinetics by computer assisted sperm analysis (CASA); viability; morphology; HOST; DNA integrity) were evaluated at 6 and 24 h. Semen data were analyzed by a mixed model for repeated measures and microbiological data with Student's t-test for paired samples. At 6 h of storage, VCL and rapid movement-spermatozoa, and at 24 h, total/progressive motility and amplitude of lateral head displacement (ALH) were significantly decreased in group Ag compared to control. In group Fe, progressive/rapid movement-spermatozoa were significantly lower compared to control after 24 h of storage. Only in group Ag was a significant reduction of total bacterial count revealed. In conclusion, the examined Fe NPs demonstrated slight antibacterial effect, while the examined Ag NPs provided higher antibacterial properties accompanied by cytotoxicity.

Zinc Nanoparticles Ameliorate the Reproductive Toxicity Induced by Silver Nanoparticles in Male Rats

Introduction

Silver nanoparticles (Ag-NPs) are among the most commonly used nanoparticles in different fields. Zinc nanoparticles (Zn-NPs) are known for their antioxidant effect. This study was designed to investigate the adverse effects of Ag-NPs (50 nm) on the male reproductive system and also the ameliorative effect of Zn-NPs (100 nm) against these harmful effects.

Methods

Forty adult male rats were used in this study; they were randomly divided into four equal groups: control group, Ag-NPs group, Zn-NPs group, Ag-NPs + Zn-NPs group. Ag-NPs (50 mg/kg) and/or Zn-NPs (30 mg/kg) were administered orally for 90 days.

Results

The results revealed that exposure to Ag-NPs adversely affected sperm motility, morphology, viability, and concentration. Ag-NPs also induced oxidative stress and lipid peroxidation in testicular tissue. The exposure to Ag-NPs decreased serum FSH, LH, and testosterone hormones. Additionally, comet assay revealed DNA degeneration in the testicular tissue of rats exposed to Ag-NPs. Histopathological examination showed various histological alterations in the testes of rats intoxicated with Ag-NPs. Furthermore, co-administration of Zn-NPs ameliorated most of the toxic effects of Ag-NPs via their antioxidative capacity.

Olanzapine induced reproductive toxicity in male rats

Although it is reported that olanzapine (OLZ), which is an atypical antipsychotic drug, causes sexual dysfunction in men, it is noteworthy that there is not any study evaluating the toxic effects of OLZ on the male reproductive system. In the scope of this research, it was aimed to assess the reproductive toxic effects of OLZ by oral administration of 2.5, 5, or 10 mg/kg of it to male rats for 28 days. For this purpose, sperm concentration, motility and morphology, and DNA damage were determined, and histopathological examination of testis tissue was carried out in rats. Also, the levels of serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone, which play roles in the regulation of reproductive functions, and the levels of glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA) which play roles in reproductive pathologies as oxidative stress biomarkers, were determined. According to the results, normal sperm morphology was decreased in 5 ve 10 mg/kg OLZ-administered groups, and pathological findings were evident in the testicular structure of the OLZ-administered group when compared with the control group. It was determined that serum LH, FSH, and testosterone levels were decreased in the OLZ-administered group. Also, decreases of GSH levels in testis tissue were determined and evaluated as the markers of the oxidative stress induced by OLZ in the testis. In conclusion, it was determined that reproductive toxic effects were induced in rats by OLZ administration. This pathology was accompanied by alterations of the hormone levels and testicular oxidative stress.

Perspectives of Nanoparticles in Male Infertility: Evidence for Induced Abnormalities in Sperm Production

Advancement in the field of nanotechnology has prompted the need to elucidate the deleterious effects of nanoparticles (NPs) on reproductive health. Many studies have reported on the health safety issues related to NPs by investigating their exposure routes, deposition and toxic effects on different primary and secondary organs but few studies have focused on NPs’ deposition in reproductive organs. Noteworthy, even fewer studies have dealt with the toxic effects of NPs on reproductive indices and sperm parameters (such as sperm number, motility and morphology) by evaluating, for instance, the histopathology of seminiferous tubules and testosterone levels. To date, the research suggests that NPs can easily cross the blood testes barrier and, after accumulation in the testis, induce adverse effects on spermatogenesis. This review aims to summarize the available literature on the risks induced by NPs on the male reproductive system.

Ameliorating effect of leukotriene receptor antagonist in multi-organ toxicity induced in rat offspring, a possible role for epidermal growth factor

Purpose: Nowadays, there is a dramatic increase in the interest of potential impact of consumer-relevant engineered nanoparticles on pregnancy.Materials and methods: This study investigated the possible protective effect of montelukast in neonatal organ toxicity induced by maternal exposure to silver nanoparticles (AgNPs) in rats.Results: It was noticed that montelukast reduced serum urea, creatinine, renal caspase-3 immunoreactivity and IL-1β and increased total antioxidant capacity, as compared to AgNPs. In kidney and bone tissue, montelukast reduced oxidative stress parameters and TNF-α level that was increased with AgNPs. Surprisingly, montelukast administration increased epidermal growth factor (EGF) in bone and reduced it in kidney. Furthermore, as compared to AgNPs, montelukast improved histopathological picture of kidney and bone.Conclusions: In conclusion, montelukast antagonized the biochemical and histopathological changes occurred in kidneys and bones of rat offspring by maternal exposure to AgNPs, mostly by anti-oxidant, anti-apoptotic and anti-inflammatory actions with a possible role for EGF.

Toxic effects of TiO2 NPs in the blood-milk barrier of the maternal dams and growth of offspring

Titanium dioxide nanoparticles (TiO₂ NPs) are amongst the most frequently used nanomaterial in everyday consumer products, and their widespread applications have raised concerns of the consequent deleterious effects on human health, particularly to vulnerable populations, such as lactating females remains elusive. Therefore, this study was initiated to investigate the detrimental effects and toxic mechanisms induced by TiO₂ NPs in maternal dams and offspring during the lactation period. Dams were randomly divided into three groups. The water (Control; Group I) and TiO₂ NPs (100 mg/kg; Group II) were orally administered from postnatal day 1-20, respectively. The results indicated that TiO₂ NPs could cause toxicity in the dams, such as pathological damages to mammary gland tissues. The excessive accumulation of TiO₂ NPs could induce oxidative stress in the mammary gland, leading to the dysfunctional blood-milk barrier; besides, TiO₂ NPs could also be transferred to offspring via breastfeeding, causing abnormal development of infant. We further accessed the possible underlying molecular mechanism; for this, we orally administered TiO₂ NPs with vitamin E (100 mg/kg; Group III). The results revealed that toxicity induced by TiO₂ NPs was rescued. Collectively, this study presented the deleterious pathological effects of oral exposure to TiO₂ NPs in the mammary gland tissues and blood-milk barrier via the production of reactive oxygen species (ROS) in dams and developmental concerns in offspring. However, the administration of VE could mitigate the toxic effects induced by the TiO₂ NPs.

Eugenol mitigated acute lung but not spermatic toxicity of C60 fullerene emulsion in mice

C₆₀ fullerene (C₆₀) is a nano-pollutant that can damage the respiratory system. Eugenol exhibits significant anti-inflammatory and antioxidant properties. We aimed to investigate the time course of C₆₀ emulsion-induced pulmonary and spermatic harms, as well as the effect of eugenol on C₆₀ emulsion toxicity. The first group of mice (protocol 1) received intratracheally C₆₀ emulsion (1.0 mg/kg BW) or vehicle and were tested at 12, 24, 72 and 96 h (F groups) thereafter. The second group of mice (protocol 2) received intratracheally C₆₀ emulsion or vehicle, 1 h later were gavaged with eugenol (150 mg/kg) or vehicle, and experiments were done 24 h after instillation. Lung mechanics, morphology, redox markers, cytokines and epididymal spermatozoa were analyzed. Protocol 1: Tissue damping (G) and elastance (H) were significantly higher in F24 than in others groups, except for H in F72. Morphological and inflammatory parameters were worst at 24 h and subsequently declined until 96 h, whereas redox and spermatic parameters worsened over the whole period. Eugenol eliminated the increase in G, H, cellularity, and cytokines, attenuated oxidative stress induced by C60 exposure, but had no effect on sperm. Hence, exposure to C₆₀ emulsion deteriorated lung morphofunctional, redox and inflammatory characteristics and increased the risk of infertility. Furthermore, eugenol avoided those changes, but did not prevent sperm damage.

Oxidative and/or Inflammatory Thrust Induced by Silver Nanoparticles in Rabbits: Effect of Vitamin E or NSAID Administration on Semen Parameters

The aim of this research was to evaluate the inflammatory and/or oxidative damage related to silver nanoparticles (AgNPs), which are responsible for negative effects on sperm physiology and metabolism. Thirty New Zealand White rabbit bucks were divided into 5 experimental groups (6 animals/group): Control, treated with 0.9% NaCl; AgNP, treated with a 5 mM AgNP solution; LPS, treated with 50 g/kg b.w. E. coli LPS; AgNPs + NSAID, treated with an anti-inflammatory drug at 0.2 mg/kg b.w. and 5 mM AgNPs; and AgNPs + Vit E, treated with 0.18 mg/kg b.w. vitamin E and 5 mM AgNPs. Sperm quality and oxidative and inflammatory status were assessed at different times (0-60 days). Two statistical models were built: the first evaluated the effects of AgNPs and LPS (vs. Control), whereas the second evaluated the protective effect of an NSAID and vitamin E against AgNP-induced damage. Three principal component analyses were performed: sperm traits (motility, volume), oxidative status (antioxidants, oxidative metabolites, and redox reactions), and cytokines (TNF-α, IL-8, and IL-6). A negative effect on reproductive traits resulted after NP administration. In particular, an inflammatory/oxidative response took place in the reproductive tract during the first 2-3 wks of AgNP administration (cytokine and oxidative metabolite generation); the inflammatory/oxidative thrust impaired the status of rabbit tissues (seminal plasma, sperm, and blood), inducing a response (increased antioxidant enzymes and redox reactions) at 4-7 wks; oxidative stress, if not totally counteracted, likely induced toxicity in the late phases of AgNP administration (8-9 wks). In conclusion, exposure to silver nanoparticles produced a similar but more persistent effect than that of LPS on rabbit reproductive tissues: AgNP administration triggered a proinflammatory response linked to oxidative thrust, worsening many sperm parameters. However, only anti-inflammatory treatment counteracted the negative effects of AgNPs, whereas vitamin E seemed to act as an adjuvant, attenuating the oxidative cascade.

Cellular, Molecular and Biochemical Impacts of Silver Nanoparticles on Rat Cerebellar Cortex

BACKGROUND

The excessive exposure to silver nanoparticles (Ag-NPs) has raised concerns about their possible risks to the human health. The brain is a highly vulnerable organ to nano-silver harmfulness. The aim of this work was to evaluate the impacts of Ag-NPs exposure on the cerebellar cortex of rats.

METHODS

Rats were assigned to: Control, vehicle control and Ag-NP-exposed groups (at doses of 10 mg and 30 mg/kg/day). Samples were processed for light and electron microscopy examinations. Immunohistochemical localization of c-Jun N-terminal kinase (JNK), nuclear factor kappa beta (NF-κB) and calbindin D28k (CB) proteins was performed. Analyses of expression of DNA damage inducible transcript 4 (Ddit4), flavin containing monooxygenase 2 (FMO2) and thioredoxin-interacting protein (Txnip) genes were done. Serum levels of inflammatory cytokines were also measured.

RESULTS

Ag-NPs enhanced apoptosis as evident by upregulation of Ddit4 gene expressions and JNK protein immune expressions. Alterations of redox homeostasis were verified by enhancement of Txnip and FMO2 gene expressions, favoring the activation of inflammatory responses by increasing NF-κB protein immune expressions and serum inflammatory mediator levels. Another cytotoxic effect was the reduction of immune expressions of the calcium regulator CB.

CONCLUSION

Ag-NPs exposure provoked biochemical, cellular and molecular changes of rat cerebellar cortex in a dose-dependent manner.

The Effects of Gold Nanoparticles on Leydig Cells and Male Reproductive Function in Mice

Background

Gold nanoparticles (AuNPs) have shown great promise in various biomedical applications, but their effects on male reproductive function remain to be ascertained. The aim of this study was to investigate the uptake, cytotoxicity and testosterone production inhibition of AuNPs in mouse Leydig cells, as well as their accumulation in the testes of male mice and their effects on male reproductive function.

Results

AuNPs (5 nm) were able to be internalized into the endosomes/lysosomes of TM3 Leydig cells, induce the formation of autophagosomes, increase the production of reactive oxygen species (ROS), and disrupt the cell cycle in S phase, resulting in concentration-dependent cytotoxicity and DNA damage. Interestingly, AuNPs significantly reduced testosterone production in TM3 cells by inhibiting the expression of 17α-hydroxylase, an important enzyme in androgen synthesis. After repeated intravenous injection, AuNPs gradually accumulated and retained in the testes of male BALB/c mice in a dose-dependent manner. One week after withdrawal, the level of plasma testosterone in the 0.5 mg/kg AuNPs group was significantly reduced compared to that in the PBS control group, accompanied by the decreased expression of 17α-hydroxylase in the testes. In addition, AuNPs treatment significantly increased the rate of epididymal sperm malformation, but without affecting fertility.

Conclusion

Our results suggest that AuNPs can accumulate in the testes and reduce testosterone production in Leydig cells by down-regulating the expression of 17α-hydroxylase, thus affecting the quality of epididymal sperm.

Alterations in reproductive parameters and gene expression in Balb/c mice testes after exposure to silver nanoparticles

Silver nanoparticles (AgNPs) have become one of the most common nanomaterials in various commercial products; however, its potential toxicity to the male reproductive system and the possible mechanisms remains unknown. Our study aimed to investigate the toxicity of silver nanoparticle (AgNPs) in the testis and to elucidate its possible mechanisms. We exposed 6-week-old Balb/c male mice to AgNP daily [0 (control), 30 or 125 mg/kg BW] for 90 days. The histological structure, sperm production and levels of reproductive hormones were assessed; we also observed apoptotic cell nuclei and the ultrastructural characteristics of the testis. Microarray analyses were used to identify differentially expressed genes, and dysregulated apoptosis-related genes and protein were also analysed. Our results indicated that 125 mg/kg AgNP changed testis morphology and decreased sperm production. AgNP treatment also increased apoptosis of germ cells and induced the presence of swollen or dissolved mitochondria in the testis. Microarray analysis showed the expression of 383 genes was altered by AgNP treatment, with apoptosis-related genes showing the greatest changes. Furthermore, we verified dysregulated apoptosis-related genes and proteins (caspase3 and Myc). These results demonstrated that AgNP induced changes of testis morphology, sperm production and apoptosis-related genes, suggested this process maybe associated with apoptosis.

Risperidone induced reproductive toxicity in male rats targeting leydig cells and hypothalamic-pituitary-gonadal axis by inducing oxidative stress

Risperidone (RIS), a commonly used drug during a lifetime for the treatment of schizophrenia, causes some adverse effects in the male reproductive system; however, there is no comprehensive reproductive toxicity study of RIS. For this purpose, male rats were administered orally for 1.25, 2.5 and 3 mg/kg RIS for 28 days and the sperm count, motility, morphology, DNA damage and the histological changes in testicular tissue were evaluated. Follicle-stimulating hormone (FSH), luteinising hormone (LH) and serum levels of testosterone, which are the main hormonal regulators of reproduction, and testicular glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA) levels as the indicators of oxidative stress were determined. Normal sperm morphology was decreased in RIS groups and histopathological degeneration occurred in testis tissue dose-dependently. Serum LH levels were not altered; however, FSH and testosterone levels decreased in the high-dose group. Histopathologic examination showed RIS toxicity targeted Leydig cells, which might be associated with impairment of the hypothalamic-pituitary-gonadal (HPG) axis. GSH levels were decreased and MDA levels were increased in the high-dose group which was evaluated as indicators of oxidative stress. In conclusion, RIS caused reproductive toxicity in male rats by inducing oxidative stress and disrupting hormonal regulation.

Therapeutic effects of rocket seeds (Eruca sativa L.) against testicular toxicity and oxidative stress caused by silver nanoparticles injection in rats

Silver nanoparticles (AgNPs), one of the most well-known nanomaterials, are regularly utilized in everyday consumer products. The present study aimed to investigate the testicular toxicity and oxidative stress by AgNPs and the therapeutic role of the rocket seeds (Eruca sativa) in treatments. Forty male Wistar rats were divided into four equivalent groups (group 1, control; group 2, rocket seeds extract [RS]; group 3, AgNPs; group 4, AgNPs+RS). Our results showed that AgNPs induced a significant decrease in serum total testosterone, FSH (follicle-animating hormone), prolactin and LH (luteinizing hormone), testicular glutathione (GSH), superoxide dismutase (SOD), and glutathione S-transferase (GST). In contrast, a significant increase in testicular DNA, injury, testicular thiobarbituric acid, proliferating cell nuclear antigen, and tumor necrosis factor-α (TNFα) expressions after treatments with AgNPs when contrasted with the control group. Treatments of AgNPs with rocket seeds extract (AgNPs+RS) improved testicular functions and structure. Rocket seeds extract might offer benefits against the toxic nature of AgNPs.

Nanotechnology-based Drug Delivery, Metabolism and Toxicity

BACKGROUND

Nanoparticles (NPs) are being used extensively owing to their increased surface area, targeted delivery and enhanced retention. NPs have the potential to be used in many disease conditions. Despite widespread use, their toxicity and clinical safety still remain a major concern.

OBJECTIVE

The purpose of this study was to explore the metabolism and toxicological effects of nanotherapeutics.

METHODS

Comprehensive, time-bound literature search was done covering the period from 2010 till date. The primary focus was on the metabolism of NP including their adsorption, degradation, clearance, and bio-persistence. This review also focuses on updated investigations on NPs with respect to their toxic effects on various in vitro and in vivo experimental models.

RESULTS

Nanotechnology is a thriving field of biomedical research and an efficient drug delivery system. Further their applications are under investigation for diagnosis of disease and as medical devices.

CONCLUSION

The toxicity of NPs is a major concern in the application of NPs as therapeutics. Studies addressing metabolism, side-effects and safety of NPs are desirable to gain maximum benefits of nanotherapeutics.

Coexposed nanoparticulate Ag alleviates the acute toxicity induced by ionic Ag+in vivo

Health concerns of silver nanoparticles (AgNPs) emerged with the increase of their industrial and biomedical application and thus human exposure. The highly dynamic properties of AgNPs lead to coexposure to nanoparticulate and ionic silver, and the combined effects of different Ag species might alter their individual toxicity. Herein, the toxicity of AgNPs combined with ionic Ag⁺ toward the rat was investigated after intravenous (i.v.) exposure to either AgNPs (5 mg/kg), Ag⁺ (5 mg/kg), or a mixture of Ag⁺ and AgNPs (5 mg/kg for both). Comparable results by histopathological and biochemical studies revealed that the exposure to individual AgNPs causes no apparent toxicity in rats, while Ag⁺ ions at the same dose induced marked acute toxicity. More importantly, while there was a negligible combined effect on the Ag accumulation, the less toxic AgNPs ameliorated Ag⁺ induced toxicity to rat organs after coexposure to the mixture of Ag⁺ and AgNPs, which might result from the complexation of Ag⁺ with the thiols like metallothioneins. Therefore, the combined toxicity of particulate and ionic Ag was complicated by their individual toxicities and also their interaction with intracellular detoxification biomolecules, regardless of differences in Ag accumulation. Although further investigations are still needed for the potential toxic mechanisms of the coexposed AgNPs and Ag⁺, considerations of the combined toxicity of different Ag species will reflect more accurate assessments of their health impacts.

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

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 μL of AgNPs solution (0.46 µg-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.

Toxicity and antimicrobial effect of silver nanoparticles in swine sperms

Bacterial contamination in swine semen affects the quality and longevity of sperm and consequently fertility is reduced. Antibiotics have been used to prevent bacterial growth, but the frequency of bacterial resistance to various antibiotics are increasing. Silver nanoparticles (AgNPs) of 10-20 nm in size have shown a biocide effect in bacteria and fungi microorganisms without toxicity to certain mammalian cells. The goal of this study was to analyze both, antimicrobial activity against Staphylococcus aureus and toxicity in swine sperms after 10-20 nm AgNPs treatment. S. aureus proliferation decreased when concentrations from 0.4 to 10 mM AgNPs were assayed. Also, sperm viability measured by mitochondrial metabolism after AgNPs treatment up to a concentration of 10 mM, was viable. In addition, viability determined by membrane integrity of sperms showed that AgNPs treatment up to a concentration of 10 mM was safe. Sperm morphology was evaluated by automated quantification of proximal and distal drops and whiptails. Data indicated that AgNPs treatment up to a concentration of 4 mM were harmless. Finally, sperm capacitation and acrosome reactions were determined by (chlortetracycline) CTC assay. Data showed that no changes in sperm capacitation were observed when sperms were treated with 2 mM of AgNPs, but data showed increased calcium mobilization when treated with 10 mM AgNPs, which suggested sperm capacitation. Finally, there were no significant changes encountered on sperm acrosome reaction for any of the treatments after AgNPs treatment. Taken together, these results show the potential of AgNPs as an alternative to conventional antimicrobial agents that are currently used in extenders to preserve semen required for storage.

ABBREVIATIONS

AgNPs: silver nanoparticles; AMK: amikacin; AMP: adenosine monophosphate; AR: acrosome reaction; C: capacitation; CF: cefallotin; CFU: colony-forming unit; CTC: chlortetracycline; CXM: cefuroxime; DMSO: dimethyl sulfoxide; NC: non-capacitation; NOM: Norma Oficial Mexicana; PBS: phosphate buffered saline; RLUs: relative light units; ROS: reactive oxygen species; SQS: Seminal Quality System.