Polystyrene nanoplastics aggravate reproductive system damage in obese male mice by perturbation of the testis redox homeostasis

Nano and Microplastics: Unveiling Their Profound Impact on Endocrine Health

Plastics are extensively used materials with a long environmental lifespan, posing significant risks to human health and the environment. Global plastic consumption has surged, with plastic waste expected to triple by 2060. The primary concern is the breakdown of plastics into nano and micro-sized particles, which can enter the body and have been detected in various organs and tissues.This review systematically examines the effects of micro and nanoplastics (MNPs) on the endocrine system using in vitro and in vivo experimental models. Following PRISMA guidelines, articles were sourced from databases like PubMed, Web of Science, and Scopus. After screening for relevance and removing duplicates and non-English articles, 103 articles focusing on the endocrine effects of MNPs were selected.MNPs can disrupt endocrine functions, altering reproductive hormones and gene expression patterns. In vivo exposure to MNPs increases inflammatory markers such as TNF-α, IL-6, IL-1β, and NF-κB, leading to apoptosis, inflammation, and oxidative stress. These disruptions impact the gonads, thyroid glands, and hormone secretion from the pituitary and hypothalamus. Most studies focus on terrestrial animals, with polystyrene being the most commonly used polymer.Future research should explore various plastic polymers, longer exposure durations, a broader range of concentrations, and human-level studies to better understand the toxicity of plastic particles. Reducing exposure to these pollutants requires legal changes, consumer behavior adjustments, and increased public awareness. Understanding the underlying processes can help propose methods to mitigate risks and protect human health.

Micro-nanoplastics pollution and mammalian fertility: A systematic review and meta-analysis

MICRO: and nanoplastics (MNPs) are fragments derived from physical, chemical, or biological degradation of plastic items. MNPs are one of the main sources of both marine and terrestrial plastic pollution. This study systematically and meta-analytically assesses the reproductive toxicity in mammals of key plastic components found in MNPs, focusing on polystyrene (PS), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and polyvinyl chloride (PVC). PubMed, Medline, and CAB Abstracts databases were used to identify the relevant scientific papers, and 79 articles were selected for the systematic review. Six articles included two different species, and 19 papers contained both in vivo and in vitro studies, resulting in a total of 102 experiments being considered and analysed in the meta-analysis. Interest in the reproductive toxicity of MNPs in mammals has increased, peaking in the last two years. Five species (rat, mouse, bovine, pig, and human) have been studied, with most experiments carried out in vivo in mice, focusing on male fertility. The most studied plastic polymer is PS, and both micro- and nanoparticles were tested at single or multiple concentrations. Toxic effects are documented across various species, particle size, and polymer type. A pronounced concentration-dependent toxicity has been observed, particularly at high concentrations/doses of MNPs. There is a gap in research on food-producing animals, which are both relevant models for human health and potential vectors for MNPs into the human food supply chain. Overall, these findings emphasizpe the importance of continued research to elucidate the pathways and mechanisms through which MNPs impact mammalian reproductive health, ultimately advancing our understanding of how these pervasive pollutants interact with biological systems across diverse species.

Exploring the potential protective role of anthocyanins in mitigating micro/nanoplastic-induced reproductive toxicity: A steroid receptor perspective

Microplastics and nanoplastics (MPs/NPs) are ubiquitous environmental pollutants that act as endocrine-disrupting chemicals (EDCs), raising significant concerns about their impact on human health. Research highlights the hazardous effects of MPs/NPs on both male and female reproductive systems, influencing germ cells, embryo development, and progeny. Additionally, studies show that MPs/NPs affect the gene expression of anabolic steroid hormones in vitro and in vivo, inducing reproductive toxicity through mechanisms such as oxidative stress and inflammation. Considering these adverse effects, identifying natural compounds that can mitigate the toxicity of MPs/NPs is increasingly important. Plants offer a wealth of antioxidants and anti-inflammatory compounds that can counteract these harmful effects. Among these, anthocyanins, natural colorants responsible for the vibrant hues of fruits and flowers, exhibit a wide range of biological activities, including antioxidant, anti-inflammatory, and anti-neoplastic properties. Moreover, anthocyanins can modulate sex hormone levels and alleviate reproductive toxicity. Cyanidin-3-glucoside (C3G), one of the most extensively studied anthocyanins, shows promise in reducing reproductive toxicity, particularly in females, and in protecting male reproductive organs, including the testis and epididymis. This protective effect is believed to result from its interaction with steroid receptors, specifically the androgen and estrogen receptors (ERs). These findings highlight the need to explore the mechanisms by which anthocyanins mitigate the reproductive toxicity caused by MPs/NPs. This review provides novel insights into how natural compounds can be leveraged to lessen the impact of environmental contaminants on human health, especially concerning reproductive health.

Teratological, neurochemical and histomorphic changes in the limbic areas of F1 mice progeny due to co-parental polystyrene nanoplastic exposure

In the present study, co-parental exposure to polystyrene nanoplastics (PS-NPs) elicits profound teratological impacts, including skeletal and visceral malformations, post-natal effects on neonatal growth and neurobehavioral development in F1 progeny. A comprehensive investigation was conducted on Swiss albino mice fetuses, neonates (PND 1-21) and adult mice offsprings (PND 60) following parental exposure during spermatogenesis and oogenesis period, as well as continued maternal exposure during gestation and weaning. The parental mice were administered PS-NPs via oral gavage at low dose (0.2 mg/kg/day) and high dose (1 mg/kg/day). Both male and female parental mice were exposed to PS-NPs for 60 days and 14 days, respectively before mating. After the mating, the pregnant female mice continued to receive PS-NPs treatment during the gestation, till the subsequent weaning period. Our findings revealed that PS-NPs led to significant reductions in growth, and heightened skeletal and visceral anomalies in developing fetuses. Exposure further impaired reflexes in neonatal mice such as grasping, surface righting and negative geotaxis. Moreover, the adult progeny also exhibited learning impairments. Neurodevelopmental assessment unveiled alterations in neurotransmitter levels, antioxidant enzyme activities, and structural changes in key limbic areas such as the cortex, hippocampus, and hypothalamus of adult mice offspring. These alterations included increased vacuolization, vascular dilation, and reduced pyramidal neurons in the hippocampus. Thus, this transgenerational study underscores the detrimental effects of PS-NPs on both prenatal and postnatal development, emphasizing teratological and enduring neurological consequences in the limbic regions of F1 progeny mice brains.

Environmental toxins and reproductive health: unraveling the effects on Sertoli cells and the blood-testis barrier in animals†

Environmental pollution is an inevitable ecological issue accompanying the process of socialization, with increasing attention to its impacts on individual organisms and ecological chains. The reproductive system, responsible for transmitting genetic material in animals, is one of the most sensitive systems to environmental toxins. Research reveals that Sertoli cells are the primary target cells for the action of environmental toxins. Different environmental toxins mostly affect the blood-testis barrier and lead to male reproductive disorders by disrupting Sertoli cells. Therefore, this article provides an in-depth exploration of the toxic mechanisms of various types of environmental toxins on the male testes. It reveals the dynamic processes of tight junctions in the blood-testis barrier affected by environmental toxins and their specific roles in the reconstruction process.

Polystyrene nanoplastics exposure triggers spermatogenic cell senescence via the Sirt1/ROS axis

Polystyrene nanoplastics (PS-NPs) have been reported to accumulate in the testes and constitute a new threat to reproductive health. However, the exact effects of PS-NPs exposure on testicular cells and the underlying mechanisms remain largely unknown. The C57BL/6 male mice were orally administered with PS-NPs (80 nm) at different dosages (0, 10, and 40 mg/kg/day) for 60 days, and GC-1 cells were treated with PS-NPs in this study. Enlarged seminiferous tubule lumens and a loose and vacuolated layer of spermatogenic cells were observed in PS-NPs-exposed mice. Spermatogenic cells which may be one of the target cells for this reproductive damage, were decreased in the mice from PS-NPs group. PS-NPs caused spermatogenic cells to undergo senescence, manifested as elevated SA-β-galactosidase activity and activated senescence-related signaling p53-p21/Rb-p16 pathways, and induced cell cycle arrest. Mechanistically, Gene Ontology (GO) enrichment suggested the key role of reactive oxygen species (ROS) in PS-NPs-induced spermatogenic cell senescence, and this result was confirmed by measuring ROS levels. Moreover, ROS inhibition partially attenuated the senescence phenotype of spermatogenic cells and DNA damage. Using the male health atlas (MHA) database, Sirt1 was filtrated as the critical molecule in the regulation of testicular senescence. PS-NPs induced overexpression of the main ROS generator Nox2, downregulated Sirt1, increased p53 and acetylated p53 in vivo and in vitro, whereas these disturbances were partially restored by pterostilbene. In addition, pterostilbene intervention significantly alleviated the PS-NPs-induced spermatogenic cell senescence and attenuated ROS burst. Collectively, our study reveals that PS-NPs exposure can trigger spermatogenic cell senescence mediated by p53-p21/Rb-p16 signaling by regulating the Sirt1/ROS axis. Importantly, pterostilbene intervention may be a promising strategy to alleviate this damage.

Adverse effects and potential mechanisms of polystyrene microplastics (PS-MPs) on the blood-testis barrier

Microplastics (MPs) are defined as plastic particles or fragments with a diameter of less than 5 mm. These particles have been identified as causing male reproductive toxicity, although the precise mechanism behind this association is yet to be fully understood. Recent research has found that exposure to polystyrene microplastics (PS-MPs) can disrupt spermatogenesis by impacting the integrity of the blood-testis barrier (BTB), a formidable barrier within mammalian blood tissues. The BTB safeguards germ cells from harmful substances and infiltration by immune cells. However, the disruption of the BTB leads to the entry of environmental pollutants and immune cells into the seminiferous tubules, resulting in adverse reproductive effects. Additionally, PS-MPs induce reproductive damage by generating oxidative stress, inflammation, autophagy, and alterations in the composition of intestinal flora. Despite these findings, the precise mechanism by which PS-MPs disrupt the BTB remains inconclusive, necessitating further investigation into the underlying processes. This review aims to enhance our understanding of the pernicious effects of PS-MP exposure on the BTB and explore potential mechanisms to offer novel perspectives on BTB damage caused by PS-MPs.

Combined effects of polystyrene nanoplastics and lipopolysaccharide on testosterone biosynthesis and inflammation in mouse testis

Microplastics (MPs)/nanoplastics (NPs), as a source and vector of pathogenic bacteria, are widely distributed in the natural environments. Here, we investigated the combined effects of polystyrene NPs (PS-NPs) and lipopolysaccharides (LPS) on testicular function in mice for the first time. 24 male mice were randomly assigned into 4 groups, control, PS-NPs, LPS, and PS-NPs + LPS, respectively. Histological alterations of the testes were observed in mice exposed to PS-NPs, LPS or PS-NPs + LPS. Total sperm count, the levels of testosterone in plasma and testes, the expression levels of steroidogenic acute regulatory (StAR) decreased more remarkable in testes of mice treated with PS-NPs and LPS than the treatment with LPS or PS-NPs alone. Compared with PS-NPs treatment, LPS treatment induced more sever inflammatory response in testes of mice. Moreover, PS-NPs combined with LPS treatment increased the expression of these inflammatory factors more significantly than LPS treatment alone. In addition, PS-NPs or LPS treatment induced oxidative stress in testes of mice, but their combined effect is not significantly different from LPS treatment alone. These results suggest that PS-NPs exacerbate LPS-induced testicular dysfunction. Our results provide new evidence for the threats to male reproductive function induced by both NPs and bacterial infection in human health.

Investigating the Impact of Carbon Nanotube Nanoparticle Exposure on Testicular Oxidative Stress and Histopathological Changes in Swiss albino Mice

Carbon nanotubes (CNTs) possess remarkable properties that make them valuable for various industrial applications. However, concerns have arisen regarding their potential adverse health effects, particularly in occupational settings. The main aim of this research was to examine the effects of short-term exposure to multiwalled carbon nanotube nanoparticles (MWCNT-NPs) on testicular oxidative stress in Swiss albino mice, taking into account various factors such as dosage, duration of exposure, and particle size of MWCNT-NP. In this study, 20 mice were used and placed into six different groups randomly. Four of these groups comprised four repetitions each, while the two groups served as the vehicle control with two repetitions each. The experimental groups received MWCNT-NP treatment, whereas the control group remained untreated. The mice in the experimental groups were exposed to MWCNT-NP for either 7 days or 14 days. Through oral administration, the MWCNT-NP solution was introduced at two distinct dosages: 0.45 and 0.90 μg, whereas the control group was subjected to distilled water rather than the MWCNT-NP solution. The investigation evaluated primary oxidative balance indicators-glutathione (GSH) and glutathione disulfide (GSSG)-in response to MWCNT-NP exposure. Significantly, a noticeable reduction in GSH levels and a concurrent increase in GSSG concentrations were observed in comparison to the control group. To better understand and explore the assessment of the redox status, the Nernst equation was used to calculate the redox potential. Intriguingly, the calculated redox potential exhibited a negative value, signifying an imbalance in the oxidative state in the testes. These findings suggest that short-term exposure to MWCNT-NP can lead to the initiation of testicular oxidative stress and may disrupt the male reproductive system. This is evident from the alterations observed in the levels of GSH and GSSG, as well as the negative redox potential. The research offers significant insights into the reproductive effects of exposure to MWCNTs and emphasizes the necessity of assessing oxidative stress in nanomaterial toxicity studies.

Mapping the Landscape of Obesity Effects on Male Reproductive Function: A Bibliometric Study

BACKGROUND

Due to changes in lifestyle and dietary habits, the global population with obesity is increasing gradually, resulting in a significant rise in the number of individuals having obesity. Obesity is caused by an imbalance between energy intake and consumption, leading to excessive fat accumulation, which interferes with normal human metabolism. It is also associated with cardiovascular disease, metabolic syndrome, male reproductive endocrine regulation disorders, systemic and local inflammatory reactions, excessive oxidative stress, and apoptosis. All these factors can damage the internal environment for sperm generation and maturation, resulting in male sexual dysfunction, a decline in sperm quality, and lower fertility. This study analyzes the trends and priorities of the effects of obesity on male reproductive disorders from a bibliometric perspective.

METHODS

This study uses the Web of Science as the statistical source, covering all time spans. Tools like Web of Science, VOSviewer, and CiteSpace are used to analyze countries, institutions, authors, journals, and keywords in the field. Total publications, total citations, and average number of citations are selected for statistics.

RESULTS

The results show that the research on the impact of obesity on male reproductive function can be roughly divided into three stages: the initial stage, the slow development stage, and the rapid development stage. Our statistical scope includes 463 highly relevant articles that we have screened. We found that the journal with the most publications in this field is Andrologia, and the institution with the highest total citations is the University of Utah. The most influential countries, institutions, and authors in this field are the United States, the University of Utah, and Carrell, Douglas. Currently, research related to the impact of obesity on male reproduction focuses mainly on three aspects: biochemistry, molecular biology, and reproductive biology. The keyword explosion results indicate that sperm, obesity, and male reproduction are at the forefront and trends of future research in this field. There has been a shift from basic biochemical and molecular research to research on molecular mechanisms relying on omics technologies. However, we have observed that the number of papers published in 2022 is lower than in 2021, indicating a growth interruption during this period. Considering that this deviation may be due to the impact of the COVID-19 pandemic, it may hinder the progress of certain experiments in 2022. In recent years, China has rapidly developed research in this field. However, the average citation rate is relatively low, indicating the need for Chinese scholars to improve the quality of their articles further. Based on our research and in the context of global obesity, men are at risk of increased infertility. Addressing this issue relies on our continued research into the mechanisms of obesity-related male reproductive disorders. Over the past forty-three years, with the contributions of scientists worldwide, research in this field has flourished.

CONCLUSION

The impact of obesity on male reproductive disorders has been extensively studied. Currently, research in this field primarily focuses on male sperm function, sperm quality, and the effects or mechanisms of cells on male reproduction. Future trends in this field should concentrate on the relationship between male fertility and energy metabolism, as well as the endocrine function of adipose tissue. This study comprehensively analyzes the current research status and global trends in obesity and male reproductive disorders. We also discuss the future developments in this field, making it easier for researchers to understand its developmental history, current status, and trends, providing valuable reference for effective exploration in this area.