Genetic, reproductive and oxidative damage in mice triggered by co-exposure of nanoparticles: From a hypothetical scenario to a real concern

Impact of physicochemical properties on biological effects of lipid nanoparticles: Are they completely safe

Lipid nanoparticles (LNPs) are promising materials and human-use approved excipients, with manifold applications in biomedicine. Researchers have tended to focus on improving the pharmacological efficiency and organ targeting of LNPs, while paid relatively less attention to the negative aspects created by their specific physicochemical properties. Here, we discuss the impacts of LNPs' physicochemical properties (size, surface hydrophobicity, surface charge, surface modification and lipid composition) on the adsorption-transportation-distribution-clearance processes and bio-nano interactions. In addition, since there is a lack of review emphasizing on toxicological profiles of LNPs, this review outlined immunogenicity, inflammation, hemolytic toxicity, cytotoxicity and genotoxicity induced by LNPs and the underlying mechanisms, with the aim to understand the properties that underlie the biological effects of these materials. This provides a basic strategy that increased efficacy of medical application with minimized side-effects can be achieved by modulating the physicochemical properties of LNPs. Therefore, addressing the effects of physicochemical properties on toxicity induced by LNPs is critical for understanding their environmental and health risks and will help clear the way for LNPs-based drugs to eventually fulfill their promise as a highly effective therapeutic agents for diverse diseases in clinic.

Effects of SARS-CoV-2 Vaccines on Sperm Quality: Systematic Review

BACKGROUND

The COVID-19 pandemic, caused by SARS-CoV-2, has triggered a global public health crisis of unprecedented proportions. SARS-CoV-2 vaccination is a highly effective strategy for preventing infections and severe COVID-19 outcomes. Although several studies have concluded that COVID-19 vaccines are unlikely to affect fertility, concerns have arisen regarding adverse events, including the potential impact on fertility; these concerns are plagued by limited and inconsistent evidence.

OBJECTIVE

This review aims to provide a recent assessment of the literature on the impact of COVID-19 vaccines on male sperm quality. The possible impact of COVID-19 vaccines on fertility potential was also examined to draw a clearer picture and to evaluate the effects of COVID-19 on male reproductive health.

METHODS

PubMed, Scopus, Web of Science, Embase, and Cochrane databases were searched from their inception to October 2023. Eligible studies included articles reporting SARS-CoV-2 vaccination and human semen quality and fertility, as well as the impact of vaccination on assisted reproductive technology treatment outcomes. The quality of cohort studies was assessed using the Newcastle-Ottawa Scale, and the quality of cross-sectional studies was assessed using the quality evaluation criteria recommended by the Agency for Healthcare Research and Quality. The systematic review followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines.

RESULTS

The initial literature search yielded 4691 records by searching 5 peer-reviewed databases (PubMed, Scopus, Web of Science, Embase, and Cochrane). Finally, 24 relevant studies were selected for our study. There were evident research inequalities at the regional level, with the United States and Western European countries contributing 38% (9/24) of the studies, Middle Eastern countries contributing 38% (9/24), China accounting for 21% (5/24), and Africa and South America accounting for none. Nonetheless, the overall quality of the included studies was generally good. Our results demonstrated that serious side effects of the COVID-19 vaccine are extremely rare, and men experience few problems with sperm parameters or reproductive potential after vaccination.

CONCLUSIONS

On the basis of the studies published so far, the COVID-19 vaccine is safe for male reproductive health. Obviously, vaccination is a wise option rather than experience serious adverse symptoms of viral infections. These instances of evidence may help reduce vaccine hesitancy and increase vaccination coverage, particularly among reproductive-age couples. As new controlled trials and prospective cohort studies with larger sample sizes emerge, the possibility of a negative effect of the COVID-19 vaccine on sperm quality must be further clarified.

Effect of COVID-19 vaccination on semen parameters: A systematic review and meta-analysis

The aim of this study was to investigate the effect of coronavirus disease 2019 (COVID-19) vaccination on semen parameters through systematic review and meta-analysis. PubMed, EMBASE, Web of Science, and Cochrane Library were comprehensively searched by June 2022. Studies were considered eligible if they compared semen parameters before and after COVID-19 vaccination or between vaccinated and unvaccinated men, with no restrictions on vaccine types or doses. The effect size was calculated as mean difference (MD) with 95% confidence interval (CI) using a random-effects model. Subgroup and sensitivity analyses were conducted to assess the sources of heterogeneity measured by the I² statistic, with publication bias evaluated by Egger's test. Twelve cohort studies involving 914 participants fulfilled the inclusion criteria. In a comparison of vaccinated versus unvaccinated group, the pooled data revealed no significant differences in semen volume (MD = 0.18 ml, 95% CI -0.02 to 0.38), sperm concentration (MD = 1.16 million/ml, 95% CI -1.34 to 3.66), total sperm motility (MD = -0.14%, 95% CI -2.84 to 2.56), progressive sperm motility (MD = -1.06%, 95% CI -2.88 to 0.77), total sperm count (MD = 5.92 million, 95% CI -10.22 to 22.05), total motile sperm count (MD = 2.18 million, 95% CI -1.28 to 5.63), total progressively motile sperm count (MD = -3.87 million, 95% CI -13.16 to 5.43), and sperm morphology (MD = 0.07%, 95% CI -0.84 to 0.97). The results also remained similar across messenger ribonucleic acid, viral-vector, and inactivated COVID-19 vaccines. Sensitivity analysis identified two individual studies that contributed to heterogeneity, while the effect size was not materially altered. No obvious publication bias was detected among included studies. Our finding suggested that COVID-19 vaccination had no detrimental impact on semen quality, which could be potentially helpful to reduce male vaccine hesitancy and increase vaccination coverage.

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.

Bio-Receptors Functionalized Nanoparticles: A Resourceful Sensing and Colorimetric Detection Tool for Pathogenic Bacteria and Microbial Biomolecules

Pathogenic bacteria and several biomolecules produced by cells and living organisms are common biological components posing a harmful threat to global health. Several studies have devised methods for the detection of varying pathogenic bacteria and biomolecules in different settings such as food, water, soil, among others. Some of the detection studies highlighting target pathogenic bacteria and biomolecules, mechanisms of detection, colorimetric outputs, and detection limits have been summarized in this review. In the last 2 decades, studies have harnessed various nanotechnology-based methods for the detection of pathogenic bacteria and biomolecules with much attention on functionalization techniques. This review considers the detection mechanisms, colorimetric prowess of bio-receptors and compares the reported detection efficiency for some bio-receptor functionalized nanoparticles. Some studies reported visual, rapid, and high-intensity colorimetric detection of pathogenic bacteria and biomolecules at a very low concentration of the analyte. Other studies reported slight colorimetric detection only with a large concentration of an analyte. The effectiveness of bio-receptor functionalized nanoparticles as detection component varies depending on their selectivity, specificity, and the binding interaction exhibited by nanoparticles, bio-receptor, and analytes to form a bio-sensing complex. It is however important to note that the colorimetric properties of some bio-receptor functionalized nanoparticles have shown strong and brilliant potential for real-time and visual-aided diagnostic results, not only to assess food and water quality but also for environmental monitoring of pathogenic bacteria and a wide array of biomolecules.

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.

Bisphenol A-induced Alterations in Different Stages of Spermatogenesis and Systemic Toxicity in Albino Mice (Mus musculus)

BACKGROUND

Bisphenol A (BPA) is known to alter sperm morphology, but information is limited on the most susceptible stage(s) of spermatogenesis, especially in mice.

OBJECTIVES

This study investigated the reproductive, biochemical, and hematological changes caused by exposure to BPA in male albino mice. The genotoxicity of BPA to the six stages of spermatogenesis in mice was determined.

METHODS

Mice were exposed orally to BPA at 0.5, 1.0, 2.0, and 5.0 mg/kg bw doses for 5 days and assessed for sperm morphology after 35 days. Based on the result, the second group of mice was exposed to BPA at 1.0 mg/kg bw dose for 5 days, their spermatozoa were assessed for sperm morphology based on BPA exposure at the 6 maturation stages of spermatogenesis: spermatozoa, elongating spermatids, round spermatids, secondary spermatocytes, primary spermatocytes, and spermatogonia. Biochemical and hematological analyses of the blood of exposed mice were also carried out.

RESULTS

The results showed that BPA induced concentration-dependent, significantly (p<0.05) increased sperm cell abnormalities at three of the four concentrations tested, with the exception of 0.5 mg/kg bw, in comparison with the negative control. The highest frequency of sperm aberrations was induced in spermatozoa exposed to BPA while at the primary spermatocytes. The order of induced sperm abnormality at the different stages of exposure was: primary spermatocytes > elongating spermatids > spermatozoa > spermatogonia > round spermatids > secondary spermatocytes. The results of the biochemical analysis showed significantly (p<0.05) increased serum urea, creatinine, and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities with a concomitant decrease in total protein content at the various stages of spermatogenesis. In addition, the results for hematological parameters showed several significant (p<0.05) modulations in mice exposed to BPA.

CONCLUSIONS

These data showed that BPA is most toxic to primary spermatocytes and alterations of biochemical and hematological parameters might be the mechanisms of induced toxicity.

ETHICS APPROVAL

The Research Ethics Committee, Federal University of Technology, Akure approved the study protocols.

COMPETING INTERESTS

The authors declare no competing financial interests.

Co-exposure of iron oxide nanoparticles and glyphosate-based herbicide induces DNA damage and mutagenic effects in the guppy (Poecilia reticulata)

Iron oxide nanoparticles (IONPs) have been tested to remediate aquatic environments polluted by chemicals, such as pesticides. However, their interactive effects on aquatic organisms remain unknown. This study aimed to investigate the genotoxicity and mutagenicity of co-exposure of IONPs (γ-Fe2O3 NPs) and glyphosate-based herbicide (GBH) in the fish Poecilia reticulata. Thus, fish were exposed to citrate-functionalized γ-Fe2O3 NPs (0.3 mg L-1; 5.44 nm) alone or co-exposed to γ-Fe2O3 NPs (0.3 mg L-1) and GBH (65 and 130 μg of glyphosate L-1) during 14 and 21 days. The genotoxicity (DNA damage) was analyzed by comet assay, while the mutagenicity evaluated by micronucleus test (MN test) and erythrocyte nuclear abnormalities (ENA) frequency. The co-exposure induced clastogenic (DNA damage) and aneugenic (nuclear alterations) effects on guppies in a time-dependent pattern. Fish co-exposed to NPs and GBH (130 μg glyphosate L-1) showed high DNA damage when compared to NPs alone and control group, indicating synergic effects after 21 days of exposure. However, mutagenic effects (ENA) were observed in the exposure groups after 14 and 21 days. Results showed the potential genotoxic and mutagenic effects of maghemite NPs and GBH co-exposure to freshwater fish. The transformation and interaction of iron oxide nanoparticles with other pollutants, as herbicides, in the aquatic systems are critical factors in the environmental risk assessment of metal-based NPs.

In vitro cytotoxicity of co-exposure to superparamagnetic iron oxide and solid lipid nanoparticles

Increased production and use of different types of nanoparticles (NPs) in the last decades has led to increased environmental release of these NPs with potential detrimental effects on both the environment and public health. Information is scarce in the literature on the cytotoxic effect of co-exposure to many NPs as this concern is relatively recent. Thus, in this study, we hypothesized scenarios of cell's co-exposure to two kinds of NPs, solid lipid nanoparticles (SLNs) and superparamagnetic iron oxide nanoparticles (SPIONs), to assess the potential cytotoxicity of exposure to NPs combination. Cytotoxicity of SPIONs, SLNs, and their 1:1 mixture (MIX) in six tumor and six non-tumor cell lines was investigated. The mechanisms underlining the induced cytotoxicity were studied through cell cycle analysis, detection of reactive oxygen species (ROS), and alterations in mitochondrial membrane potential (ΔΨM). Double staining with acridine orange and ethidium bromide was also used to confirm cell morphology alterations. The results showed that SPIONs induced low cytotoxicity compared to SLNs. However, the mixture of SPIONs and SLNs showed synergistic, antagonistic, and additive effects based on distinct tests such as viability assay, ROS generation, ΔΨM, and DNA damage, depending on the cell line. Apoptosis triggered by ROS and disturbances in ΔΨM are the most probable related mechanisms of action. As was postulated, there is possible cytotoxic interaction between the two kinds of NPs.

Toxicity associated with long term use of aluminum cookware in mice: A systemic, genetic and reproductive perspective

Studies on the toxic effects of cooking with aluminum pots are limited and none of them have explored its impact on the genetic material in germ and somatic cells. Therefore, this study investigated the cytogenotoxic effect of boiled water from new, 3- and 6-year old aluminum pots in germ and somatic cells viz-a-vis mouse sperm morphology test and sperm count; and the bone marrow micronucleus test. The mice were allowed to freely drink the boiled water from the different aluminum pots for 3, 4, and 5 weeks. The heavy metal analysis showed that As, Pb, Cd, and Al were present in the boiled water samples at different concentrations with the 6-year old pot having the highest concentrations of Pb, Cd, and Al. There were duration of exposure and age of pot-dependent significant increase in abnormal sperm cells and a significant decrease total mean sperm count of exposed mice. Similarly, there was a statistically significant increase in micronucleated polychromatic erythrocytes and nuclear abnormalities in the exposed mice that increased dependently upon the age of the cookware. Finally there were significantly increased activities of serum AST and ALT; and the liver concentrations of MDA, SOD and CAT in boiled water exposed mice. The findings of this study revealed that boiled water from aluminum pots is capable of inducing cytotoxic and genotoxic effects, especially as the pot ages.

Organ-specific toxicity of magnetic iron oxide-based nanoparticles

The unique properties of magnetic iron oxide nanoparticles determined their widespread use in medical applications, the food industry, textile industry, which in turn led to environmental pollution. These factors determine the long-term nature of the effect of iron oxide nanoparticles on the body. However, studies in the field of chronic nanotoxicology of magnetic iron particles are insufficient and scattered. Studies show that toxicity may be increased depending on oral and inhalation routes of administration rather than injection. The sensory nerve pathway can produce a number of specific effects not seen with other routes of administration. Organ systems showing potential toxic effects when injected with iron oxide nanoparticles include the nervous system, heart and lungs, the thyroid gland, and organs of the mononuclear phagocytic system (MPS). A special place is occupied by the reproductive system and the effect of nanoparticles on the health of the first and second generations of individuals exposed to the toxic effects of iron oxide nanoparticles. This knowledge should be taken into account for subsequent studies of the toxicity of iron oxide nanoparticles. Particular attention should be paid to tests conducted on animals with pathologies representing human chronic socially significant diseases. This part of preclinical studies is almost in its infancy but of great importance for further medical translation on nanomaterials to practice.

Cytotoxic effects of polystyrene nanoplastics with different surface functionalization on human HepG2 cells

Nanoplastics in the environment lead to the human exposure to these particles. However, the consequences of this exposure are not yet fully understood. Here, the cytotoxicity of polystyrene nanoparticles (PS-NPs) with a uniform size (50 nm) but distinct surface functionalization (pristine polystyrene, PS; carboxy and amino functionalized, PS-COOH and PS-NH₂, respectively), and at an exposure dosage of 10, 50 and 100 μg/mL, were assessed in the human hepatocellular carcinoma (HepG2) cell line. Although all PS-NPs could be internalized by the HepG2 cells, according to the fluorescent intensities, more of PS-COOH and PS-NH₂ than PS, accumulated in the cells. The cell viability was significantly affected in a positively dose-related manner. Functionalized PS-NPs exhibited greater inhibition of cell viability than PS, and the viability inhibition peaked (46%) at 100 μg/mL of PS-NH₂ exposure. Superoxide dismutase (SOD) activity was maximum when HepG2 cells were exposed to 10 μg/mL of PS-COOH (1.8 folds higher than that without PS-COOH exposure). The glutathione (GSH) content was maximum when the cells were treated with 50 μg/mL of PS (3.75 fold increase compared to untreated cells). Although the difference in inhibition of cell viability was not significant between PS-NH₂ and PS-COOH exposure, 100 μg/mL of PS-NH₂ exposure caused the most severe oxidative stress due to dramatically increased accumulation of malondialdehyde (MDA); however, a decrease in the antioxidants levels as the SOD activity and GSH content were also found. The results demonstrated that the cellular oxidative damage occurred and that the antioxidation enzymes may not be able to maintain the balance between the generation of oxidant species and the antioxidant defense. Consequently, 100 μg/mL of PS-NH₂ exposure triggered the destruction of antioxidant structures. This study defines the cytotoxic effects of PS-NPs on HepG2 cells and emphasizes the significance of investigating the cytotoxic outcomes of nanoplastics in humans.

The emerging risk of exposure to nano(micro)plastics on endocrine disturbance and reproductive toxicity: From a hypothetical scenario to a global public health challenge

Humans are potentially exposed to nano(micro)plastics, however their interaction with tissues and cells in humans remains largely unknown. This premise is particularly notable with nano-sized plastic particulates, a potentially most pernicious form of plastic pollution. In this study, even in a hypothetical scenario in terms of dose (1, 3, 6 and 10 mg/kg-day) and exposure time (five weeks), the potential endocrine disturbances with particular reference to reproductive toxicity of polystyrene nanoplastics (PS NPs, average size = 38.92 nm) was studied in male rats considering biomarkers of semen quality, changes in hormonal milieu and molecular signatures of endocrine disruption. Sperm DNA integrity and its chromatin structure were also analyzed. There observed significant inverse associations between exposure to PS NPs and serum concentrations of testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Tissue and cell impairments were also noticed even at the lowest tested dosage, though the severity of lesions followed a clear dose-response pattern. DNA damage as well as alterations in sperm morphology and viability were evident, again proportionally with the amount of exposure dosage. RT-qPCR data were in accordance with the results of physio-histological alterations and fluorescence imaging, as significant down-regulation of PLZF, DAZL, FSH and LH gene expressions were noticed in the testis of exposed animals, suggesting that exposure interferes with spermatogenesis and also with HPT-axis. However, among those with highest exposure dosage, expressions of FSH and LH were significantly increased. ABP modulation further revealed evidence of a nonlinear dose response. The association between PS NPs exposure and GnRH was indeed in an unexpected positive direction, though these end-points were less sensitive at higher doses. Although additional evidence is warranted, the present work provides new insights into the possible risks of plastic nanoparticles exposure in humans, especially since the problem is growing and will persist for a long time.

Solid-state fermentation of ammoniated corn straw to produce feed protein and toxicological assessment of the product

Solid-state fermentation (SSF) of ammoniated corn straw was used to produce feed protein, followed by a toxicological assessment of the fermentation product. Results showed that through ammonification at 35 °C for 9 days and the subsequent SSF by the two fungi Penicillium sp. and Torula allii at 30 °C for 5 days, the contents of real protein and crude protein of the corn straw reached 29.66% and 35.41%, respectively. Toxicological assessment in mice showed that there were no significant differences (P > 0.05) for micronucleated polychromatic erythrocytes (Mn-PCEs) and sperm abnormality between dose groups and the control group. Malondialdehyde (MDA) levels and activities of superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) also showed no significant difference (P > 0.05) between tissues (heart, liver, spleen, stomach, kidney, and brain), which indicates that the fermentation product did not induce toxic effects and is safe to use as ruminant feed.

Oxidative Stress Induced DNA Damage and Reproductive Toxicity in Male Albino Mice Orally Exposed to Sorbitol

In this study, the potential DNA damage and reproductive toxicity of sorbitol was investigated using bone marrow micronucleus (MN), sperm morphology, and sperm count in mice. Five doses of 90, 45, 20, 10 and 1 mg/kg/day, defined by allometry, and approximately corresponding to 1.5g, 750mg, 330mg, 165mg and 16mg of sorbitol daily consumption by a 70kg human, respectively, were used. MN analysis showed a dose-dependent induction of micronucleated polychromatic erythrocytes and other nuclear abnormalities across the treatment groups. Assessment of sperm shape showed a significant (p < 0.05) increase in sperm abnormalities with significant (p < 0.05) decrease in mean sperm count in treated groups. The result of the oxidative stress biomarkers showed induction of significant (p < 0.05) increase in liver catalase, MDA and serum ALT and AST activities with concomitant decrease in SOD activities in exposed mice. A significant increase in weight of exposed mice were recorded when compared with the negative control. The results of this study showed the genotoxicity and reproductive effects of sorbitol.