Acute and chronic effects of gold nanoparticles on sperm parameters and chromatin structure in Mice

Susceptibility of Human Spermatozoa to Titanium Dioxide Nanoparticles: Evaluation of DNA Damage and Biomarkers

Nowadays, developing countries have seen a reduction in male reproductive parameters, and it has been linked to the exposure of endocrine disrupting chemicals (EDCs), which are able to mimic or disrupt steroid hormone actions. Also, nanoparticles have shown effects on the male reproductive system, in particular the use of TiO2-NPs in drugs, cosmetics, and food as pigment additives, and, thanks to their small size (1-100 nm), provide themselves the opportunity to be internalized by the body and pass the blood-testis barrier (BTB). Therefore, TiO2-NPs can act on spermatogenesis and spermatozoa. In this study, we carried out an in vitro assay on human spermatozoa to evaluate the effects of TiO2-NPs at the concentrations of 500, 250, 100, and 50 ppm. Exposure did not statistically alter sperm parameters (e.g., motility and viability) but induced damage to sperm DNA and the expression of biomarkers by spermatozoa. This immunofluorescence investigation showed a positivity for biomarkers of stress (HSP70 and MTs) on the connecting piece of spermatozoa and also for sex hormone binding globulin (SHBG) biomarkers. The SHBG protein acts as a carrier of androgens and estrogens, regulating their bioavailability; therefore, its expression in the in vitro assay did not rule out the ability of TiO2-NPs to act as endocrine disruptors.

Assessment of reproductive toxicity of gold nanoparticles and its reversibility in male albino rats

Nanotechnology has become a trending area in science all over the world. Although gold nanoparticles (AuNPs) have been utilized widely in biomedical fields, potential toxicities may arise from their interactions with biological systems. The current study aimed at evaluating the toxic effects of AuNPs on the reproductive system of adult male albino rats and assessing the recovery probability. In this study, AuNPs (13 ± 4 nm in diameter) were synthesized, and the experimental work was conducted on 60 adult male albino rats divided into the following groups: control group (received deionized water daily intraperitoneally (IP) for 28 days), test group, and withdrawal groups I and II (received 570 μg/kg of 13 ± 4 nm AuNPs daily IP for 28 days). Withdrawal groups I and II were left for another 30 and 60 days without sacrification, respectively. The test group showed significant decreases in final body and absolute testicular weights, testosterone hormone level, sperm count and motility, and spermatogenesis score, as well as significant increase in the percentage of sperms of abnormal morphology compared to the control group, associated with significant light and electron microscopic histopathological changes. Partial improvement of all studied reproductive parameters was detected after one month of withdrawal in withdrawal group I, and significant improvement and reversibility of all these parameters were reported after two months of withdrawal in withdrawal group II. So, AuNPs induce male reproductive toxicity, which partially improves after one month of withdrawal and significantly improves and reverses after two months of withdrawal.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-023-00203-2.

Application of conventional metallic nanoparticles on male reproductive system - challenges and countermeasures

The application of nanotechnology in the present era has substantial impact on different industrial and medical fields. However, the advancement in nanotechnology for potential therapeutic and consumer benefits has been an anxious cause regarding the probable hazardous consequences of these molecules in biological systems and the environment. The toxic effects can perturb the physiologic system broadly and reproductive function and fertility specifically. Despite engineered nanomaterials (ENMs) having a wide range of applications, toxicological investigations of the probable ramifications of ENMs on the reproductive systems of mammals and fertility remains in its nascence. Complication in the male reproductive system is quite a pertinent issue in today's world which comprises of benign prostatic enlargement, prostate cancer, and unhealthy sperm production. The therapeutic drugs should not only be active in minimum dose but also site-specific in action, criteria being met by nanomedicines. Nanomedicine therapy is promising but encompasses the chances of adverse effects of being cytotoxic and generating oxidative stress. These hurdles can be overcome by creating coated nanoparticles with organic substances, modification of shape and size, and synthesizing biocompatible green nanoparticles. This review attempts to look into the applications of most widely used metals like zinc, titanium, silver, and gold nanoparticles in the therapy of the male reproductive system, their prospective harmful effects, and the way out to create a safe therapeutic system by specific modifications of these metal and metal oxide nanoparticles.

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.

A Perspective on Reproductive Toxicity of Metallic Nanomaterials

Nanotechnological tools have been greatly exploited in all possible fields. However, advancement of nanotechnology has raised concern about their adverse effects on human and environment. These deleterious effects cannot be ignored and need to be explored due to safety purpose. Several recent studies have demonstrated possible health hazard of nanoparticles on organism. Moreover, studies showed that toxicity of metallic nanomaterial could also lead to reproductive toxicity. Various deleterious effects have demonstrated decreased sperm motility, increased abnormal spermatozoa, altered sperm count, and altered sperm morphology. Morphological and ultrastructural changes also have been reported due to the accumulation of these nanomaterials in reproductive organs. Nonetheless, studies also suggest crossing of metallic nanoparticles through blood testes barrier and generation of oxidative stress which plays major role in reproductive toxicity. In the present study, we have incorporated updated information by gathering all available literature about various metallic nanomaterials and risk related to reproductive system.

Potential toxicity of nanoparticles on the reproductive system animal models: A review

Over the past two decades, nanotechnology has been involved in an array of applications in various fields, including diagnostic kits, disease treatment, drug manufacturing, drug delivery, and gene therapy. But concerns about the toxicity of nanoparticles have greatly hindered their use; also, due to their increasing use in various industries, all members of society are exposed to the toxicity of these nanoparticles. Nanoparticles have a negative impact on various organs, including the reproductive system. They also can induce abortion in women, reduce fetal growth and development, and can damage the reproductive system and sperm morphology in men. In some cases, it has been observed that despite the modification of nanoparticles in composition, concentration, and method of administration, there is still damage to the reproductive organs. Therefore, understanding how nanoparticles affect the reproductive system is of very importance. In several studies, the nanoparticle toxicity effect on the genital organs has been investigated at the clinical and molecular levels using the in vivo and in vitro models. This study reviews these investigations and provides important data on the toxicity, hazards, and safety of nanoparticles in the reproductive system to facilitate the optimal use of nanoparticles in the industry.

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.

The effects of sesame oil and different doses of estradiol on testicular structure, sperm parameters, and chromatin integrity in old mice

Objective

Studies of the effects of estrogens on the male reproductive system have emphasized the role of these hormones in male fertility. Sesame oil has many phytoestrogenic compounds and may improve male fertility. This study investigated the effects of sesame oil and different concentrations of estrogen on sperm parameters and DNA integrity in male mice.

Methods

Twenty old NMRI (The Naval Medical Research Institute) male mice (40 weeks; weight, 30–35 g) were treated with sesame oil or different concentrations of estrogen (estradiol, 1 and 10 μL/kg/day) or received no treatment (controls). After 35 days, sperm parameters and DNA integrity were assessed and analyzed.

Results

Sperm count, progressive motility, and morphology were decreased in the group that received 10 μL/kg of estradiol. A remarkably lower percentage of DNA fragmentation and protamine deficiency were detected in the group that received 1 μL/kg of estradiol. In the groups that received sesame oil and 1 μL/kg of estradiol, the numbers of spermatogonia and Leydig cells were higher than in controls. The combination of sesame oil and 1 μL/kg of estradiol led to improved sperm parameters and chromatin and testicular structure.

Conclusion

Based on this study, consumption of sesame oil and a low concentration of estradiol may improve testicular function in older mice.

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.

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.

Gamete quality in a multistressor environment

Over the past few decades, accumulated evidence confirms that the global environment conditions are changing rapidly. Urban industrialization, agriculture and globalization have generated water, air and soil pollution, giving rise to an environment with a growing number of stress factors, which has a serious impact on the fitness, reproduction and survival of living organisms. The issue raises considerable concern on biodiversity conservation, which is now at risk: it is estimated that a number of species will be extinct in the near future. Sexual reproduction is the process that allows the formation of a new individual and is underpinned by gamete quality defined as the ability of spermatozoa and oocytes to interact during fertilization leading to the creation and development of a normal embryo. This review aimed to provide the current state of knowledge regarding the impact of a broad spectrum of environmental stressors on diverse parameters used to estimate and evaluate gamete quality in humans and in canonical animal models used for experimental research. Effects of metals, biocides, herbicides, nanoparticles, plastics, temperature rise, ocean acidification, air pollution and lifestyle on the physiological parameters that underlie gamete fertilization competence are described supporting the concept that environmental stressors represent a serious hazard to gamete quality with reproductive disorders and living organism failure. Although clear evidence is still limited, gamete capacity to maintain and/or recover physiological conditions is recently demonstrated providing further clues about the plasticity of organisms and their tolerance to the pressures of pollution that may facilitate the reproduction and the persistence of species within the scenario of global change. Changes in the global environment must be urgently placed at the forefront of public attention, with a massive effort invested in further studies aimed towards implementing current knowledge and identifying new methodologies and markers to predict impairment of gamete quality.

Effect of acute gold nanorods on reproductive function in male albino rats: histological, morphometric, hormonal, and redox balance parameters

In this study, we investigated the effect of acute administration of gold nanorods (AuNRs) on testicular function, sexual hormones, and oxidative stress parameters in male albino rats. Forty mature male albino rats were divided into two equal groups (n = 20/each). The first group received 1 ml saline solution intraperitoneally (i.p.). The second group received single i.p. injection of 75 μg 50 nm AuNRs/kg/bwt. Five rats from each group were sacrificed on days 1, 3, 7, and 14 post treatment and blood samples were collected for hormonal and biochemical analysis. Testes were collected from each group at each time point for histopathology, morphometric, and transmission electron microscope analyses of testis and epididymis. Results indicated that i.p. injection of AuNRs did not produce any histopathological changes. Morphometric analysis of testicular samples revealed that the height of lining epithelium was significantly (P < 0.05) higher in AuNR group on days 3 and 14 post treatment, and the minor axis of seminiferous tubules was higher (P < 0.05) in AuNR-injected rats than in control group. For the epididymis, the number of spermatozoa was significantly (P < 0.05) higher on days 7 and 14 after AuNR injection when compared with control rats. AuNRs were not detected by TEM at all time points of the experiment. Serum analysis demonstrated that total and free testosterone values significantly (P < 0.05) increased on days 1, 3, 7, and 14 post AuNR injection. LH was higher (P < 0.05) in AuNRs-injected rats on days 3, 7, and 14 post injection, while FSH values were higher (P < 0.05) in AuNR group on days 3 and 14. Malondialdehyde significantly (P < 0.05) decreased on days 3, 7, and 14 in AuNR group, while catalase, glutathione peroxidase, and superoxide dismutase values were significantly (P < 0.05) elevated on days 3, 7, and 14 in AuNRs-injected rats compared with control group. In conclusion, intraperitoneal injection of 50 nm AuNRs is safe on the reproductive function and has an antioxidant action.

Effect of copper nanoparticles and ions on spermatozoa motility of sea trout (Salmo trutta m. Trutta L.)

Nanoproducts are being increasingly used in various industrial products, leading to a greater risk of water pollution through their discharge into environment as production byproducts. Increased levels of environmental pollution with nanoproducts pose a threat to all living organisms. Nanopollutants may have toxic effects on gametes and fertilization process in species with external fertilization, thereby reducing effectiveness of reproduction or greatly impairing it. The objective of the present study was to determine the effect of copper nanoparticles (Cu and CuO) and copper ions (CuSO₄·5H₂O) on the spermatozoa motility of sea trout and compare their harmful effects. Copper nanoparticles (NPs) of primary particle size <100 nm and CuO NPs of particle size <50 nm as well as a solution of CuSO₄·5H₂O were used for the study. Concentration of the products tested (CuNPs, CuONPs, and CuSO₄·5H₂O) was expressed as mg Cu L^-1 in the media regardless of dissolution and aggregation. A suspension with concentration up to 500 mg L^-1 in an aquatic environment was tested. Spermatozoa motility under direct contact with copper at 10 s post activation was evaluated using an automated system (CASA). Copper products in an aqueous environment primarily cause a reduction of spermatozoa velocity (VCL). A significant reduction of velocity in CuSO₄·5H₂O salt solution occurred at concentration starting from 8 mg L^-1, whereas in solutions containing CuNPs and CuONPs this process is observed from 50 mg L^-1. Reduction of percentage of motile spermatozoa occurred in CuNPs from a concentration of 125 mg L^-1, while in CuONPs and CuSO₄·5H₂O, the effect began at concentration from 250 mg L^-1. In a solution of CuSO₄·5H₂O at a concentration of 500 mg L^-1, strong agglutination of sperm cells occurred and movement ceased (immobilization IC100). Exposure to CuONPs decreased the motility rate to below IC50, while for CuNPs, the motility rate reached 80%. Changes in linearity (LIN) and amplitude of head displacement (ALH) differed according to Cu products. Cu as CuSO₄·5H₂O and CuONPs impaired the LIN, while CuNPs lowered ALH. Duration of motility increased at low CuSO₄·5H₂O concentration. The effect of Cu ion on sea trout spermatozoa motility was more harmful than that of copper nanoparticles. The various copper products used affected motility parameters differently. Contamination of aqueous environment with copper primarily caused reduction in male gamete velocity, which may impair reproduction. Various copper products had different effects on LIN, ALH, and motility duration, which can also affect fertilization.

Effects of Quercetin-Loaded Nanoparticles on MCF-7 Human Breast Cancer Cells

Background and objectives: Previous studies have shown anti-tumor activity of quercetin (QT). However, the low bioavailability of QT has restricted its use. This study aimed to assess the toxic effect of QT encapsulated in solid lipid nanoparticles (QT-SLNs) on the growth of MCF-7 human breast cancer cells. Materials and Methods: MCF-7 and MCF-10A (non-tumorigenic cell line) cell lines treated with 25 µmol/mL of QT or QT-SLNs for 48 h. Cell viability, colony formation, oxidative stress, and apoptosis were evaluated to determine the toxic effects of the QT-SLNs. Results: The QT-SLNs with appropriate characteristics (particle size of 85.5 nm, a zeta potential of −22.5 and encapsulation efficiency of 97.6%) were prepared. The QT-SLNs showed sustained QT release until 48 h. Cytotoxicity assessments indicated that QT-SLNs inhibited MCF-7 cells growth with a low IC₅₀ (50% inhibitory concentration) value, compared to the free QT. QT-SLNs induced a significant decrease in the viability and proliferation of MCF-7 cells, compared to the free QT. QT-SLN significantly increased reactive oxygen species (ROS) level and MDA contents and significantly decreased antioxidant enzyme activity in the MCF-7 cells. Following QT-SLNs treatment, the expression of the Bcl-2 protein significantly decreased, whereas Bx expression showed a significant increase in comparison with free QT-treated cells. Furthermore, The QT-SLNs significantly increased apoptotic and necrotic indexes in MCF-7 cells. Viability, proliferation, oxidative stress and apoptosis of MCF-10A cells were not affected by QT or QT-SLNs. Conclusions: According to the results of this study, SLN significantly enhanced the toxic effect of QT against human breast cancer cells.

Perspectives of nanotechnology in male fertility and sperm function

Recent advances in nanotechnology have tremendously expanded its possible applications in biomedicine. Although, the effects of nanoparticles (NPs) at cellular and tissue levels have not been fully understood, some of these biological effects might be employed in assisted reproduction to improve male fertility particularly by enhancing sperm cell quality either in vivo or in vitro. This review summarises the available literature regarding the potential applications of nanomaterials in farm animal reproduction, with a specific focus on the male gamete and on different strategies to improve breeding performances, transgenesis and targeted delivery of substances to a sperm cell. Antioxidant, antimicrobial properties and special surface binding ligand functionalization and their applications for sperm processing and cryopreservation have been reviewed. In addition, nanotoxicity and detrimental effects of NPs on sperm cells are also discussed due to the increasing concerns regarding the environmental impact of the expanding use of nanotechnologies on reproduction.

Assessment of sperm morphology, chromatin integrity, and catSper genes expression in hypothyroid mice

There is an evident relationship between the fertilizing capacity of sperm and the normal morphology, quality chromatin, and motility of sperm. It is well known that thyroid hormones are the important regulators of testicular function. A correlation was found between the hypothyroidism and sperm damages. The present study was conducted to investigate the effects of hypothyroidism on sperm morphology, chromatin quality, and motility. For this purpose, 20 male mice were divided into the control and the hypothyroid groups that received 0.05% 6-n-propyl-2-thiouracil (PTU) for 35 days. Sperm morphology with Papanicolaou staining and sperm chromatin quality with both Aniline Blue (AB) and Toluidine blue (TB) staining were assessed. Besides, immunohistochemistry and real-time PCR were performed to evaluate the changes of cation sperm channel (CatSper) genes. A significant increase in the sperm chromatin condensation was found in the hypothyroid mice compared to the control mice (p < 0.05). Furthermore, a significant decrease was observed in the morphology of normal sperm in hypothyroid mice compared to the controls (p < 0.05). The results showed that Hypothyroidism could downregulate the expression of CatSper genes. Immunohistochemical data confirmed the real time-PCR results. Furthermore, the results showed that hypothyroidism could adversely affect sperm morphology, sperm chromatin condensation, and CatSper gene expression in mice and these abnormalities may be related to the excessive production of reactive oxygen species (ROS) in a hypothyroid state.