Shedding light on the impacts of gestational exposure to polystyrene nanoplastics on the reproductive performance of Poecilia reticulata female and on the biochemical response of embryos

From tissue lesions to neurotoxicity: The devastating effects of small-sized nanoplastics on red drum Sciaenops ocellatus

Nanoplastic pollution typically exhibits more biotoxicity to marine organisms than microplastic pollution. Limited research exists on the toxic effects of small-sized nanoplastics on marine fish, especially regarding their post-exposure resilience. In this study, red drum (Sciaenops ocellatus) were exposed to small-sized polystyrene nanoplastics (30 nm, PS-NPs) for 7 days for the exposure experiments, followed by 14 days of recovery experiments. Histologically, hepatic lipid droplets and branchial epithelial liftings were the primary lesions induced by PS-NPs during both exposure and recovery periods. The inhibition of total superoxide dismutase activity and the accumulation of malondialdehyde content throughout the exposure and recovery periods. Transcriptional and metabolic regulation revealed that PS-NPs induced lipid metabolism disorders and DNA damage during the initial 1-2 days of exposure periods, followed by immune responses and neurotoxicity in the later stages (4-7 days). During the early recovery stages (2-7 days), lipid metabolism and cell cycle were activated, while in the later recovery stage (14 days), the emphasis shifted to lipid metabolism and energy metabolism. Persistent histological lesions, changes in antioxidant capacity, and fluctuations in gene and metabolite expression were observed even after 14 days of recovery periods, highlighting the severe biotoxicity of small-sized PS-NPs to marine fish. In summary, small-sized PS-NPs have severe biotoxicity, causing tissue lesions, oxidative damage, lipid metabolism disorders, DNA damage, immune responses, and neurotoxicity in red drum. This study offers valuable insights into the toxic effects and resilience of small-sized nanoplastics on marine fish.

Reproductive toxicity and related mechanisms of micro(nano)plastics in terrestrial mammals: Review of current evidence

Micro(nano)plastics (MNPs) have been detected in various ecological environments and are widely used due to their stable properties, raising widespread concern about their potential human reproductive toxicity. Currently, infertility affects approximately 10-30% of couples of reproductive age globally. MNPs, as environmental pollutants, have been shown to exhibit reproductive toxicity through intrinsic mechanisms or as carriers of other hazardous substances. Numerous studies have established that MNPs of varying sizes and types can penetrate biological barriers, and enter tissues and even organelles of organisms through four main routes: dietary ingestion, inhalation, dermal contact, and medical interventions. However, historical research on the toxic effects of MNPs on reproduction mainly focused on lower and aquatic species. We conducted an inclusive review of studies involving terrestrial mammals, revealing that MNPs can induce reproductive toxicity via various mechanisms such as oxidative stress, inflammation, fibrosis, apoptosis, autophagy, disruption of intestinal flora, endocrine disruption, endoplasmic reticulum stress, and DNA damage. In terrestrial mammals, reproductive toxicity predominantly manifests as disruption in the blood-testis barrier (BTB), impaired spermatogenesis, sperm malformation, sperm DNA damage, reduced sperm fertilizing capacity, compromised oocyte maturation, impaired follicular growth, granulosa cell apoptosis, diminished ovarian reserve function, uterine and ovarian fibrosis, and endocrine disruption, among other effects. Furthermore, MNPs can traverse the maternal-fetal interface, potentially impacting offspring reproductive health. To gain a comprehensive understanding of the potential reproductive toxicity and underlying mechanisms of MNPs with different sizes, polymer types, shapes, and carried toxins, as well as to explore effective protective interventions for mitigating reproductive damage, further in-depth animal studies, clinical trials, and large-scale epidemiological studies are urgently required.

Polystyrene nanoplastics synergistically exacerbate diclofenac toxicity in embryonic development and the health of adult zebrafish

In this study, we investigated the possible ecotoxicological effect of co-exposure to polystyrene nanoplastics (PS-NPs) and diclofenac (DCF) in zebrafish (Danio rerio). After six days of exposure, we noticed that the co-exposure to PS-NP (100 μg/L) and DCF (at 50 and 500 μg/L) decreased the hatching rate and increased the mortality rate compared to the control group. Furthermore, we noted that larvae exposed to combined pollutants showed a higher frequency of morphological abnormalities and increased oxidative stress, apoptosis, and lipid peroxidation. In adults, superoxide dismutase and catalase activities were also impaired in the intestine, and the co-exposure groups showed more histopathological alterations. Furthermore, the TNF-α, COX-2, and IL-1β expressions were significantly upregulated in the adult zebrafish co-exposed to pollutants. Based on these findings, the co-exposure to PS-NPs and DCF has shown an adverse effect on the intestinal region, supporting the notion that PS-NPs synergistically exacerbate DCF toxicity in zebrafish.

Unraveling the threat: Microplastics and nano-plastics' impact on reproductive viability across ecosystems

Plastic pollution pervades both marine and terrestrial ecosystems, fragmenting over time into microplastics (MPs) and nano-plastics (NPs). These particles infiltrate organisms via ingestion, inhalation, and dermal absorption, predominantly through the trophic interactions. This review elucidated the impacts of MPs/NPs on the reproductive viability of various species. MPs/NPs lead to reduced reproduction rates, abnormal larval development and increased mortality in aquatic invertebrates. Microplastics cause hormone secretion disorders and gonadal tissue damage in fish. In addition, the fertilization rate of eggs is reduced, and the larval deformity rate and mortality rate are increased. Male mammals exposed to MPs/NPs exhibit testicular anomalies, compromised sperm health, endocrine disturbances, oxidative stress, inflammation, and granulocyte apoptosis. In female mammals, including humans, exposure culminates in ovarian and uterine deformities, endocrine imbalances, oxidative stress, inflammation, granulosa cell apoptosis, and tissue fibrogenesis. Rodent offspring exposed to MPs experience increased mortality rates, while survivors display metabolic perturbations, reproductive anomalies, and weakened immunity. These challenges are intrinsically linked to the transgenerational conveyance of MPs. The ubiquity of MPs/NPs threatens biodiversity and, crucially, jeopardizes human reproductive health. The current findings underscore the exigency for comprehensive research and proactive interventions to ameliorate the implications of these pollutants.

The invisible Threat: Assessing the reproductive and transgenerational impacts of micro- and nanoplastics on fish

Micro- and nanoplastics (MNPs), emerging as pervasive environmental pollutants, present multifaceted threats to diverse ecosystems. This review critically examines the ability of MNPs to traverse biological barriers in fish, leading to their accumulation in gonadal tissues and subsequent reproductive toxicity. A focal concern is the potential transgenerational harm, where offspring not directly exposed to MNPs exhibit toxic effects. Characterized by extensive specific surface areas and marked surface hydrophobicity, MNPs readily adsorb and concentrate other environmental contaminants, potentially intensifying reproductive and transgenerational toxicity. This comprehensive analysis aims to provide profound insights into the repercussions of MNPs on fish reproductive health and progeny, highlighting the intricate interplay between MNPs and other pollutants. We delve into the mechanisms of MNPs-induced reproductive toxicity, including gonadal histopathologic alterations, oxidative stress, and disruptions in the hypothalamic-pituitary-gonadal axis. The review also underscores the urgency for future research to explore the size-specific toxic dynamics of MNPs and the long-term implications of chronic exposure. Understanding these aspects is crucial for assessing the ecological risks posed by MNPs and formulating strategies to safeguard aquatic life.

The impact of microplastics on female reproduction and early life

Plastic pollution in our environment is one of the most important global health concerns right now. Micro- and nanoplastics (MNPs) are taken up by both humans and animals, mainly via food and water, and can pass important epithelial barriers. Indications of plastics in the blood circulation have recently been shown in both humans and farm animals, but standardized methods to quantify the exact levels of MNPs to which we are exposed are currently lacking. Potential hazards of MNPs are being investigated very recently, including the impact that MNPs may have on reproduction. However, studies on mammalian reproduction are scarce, but a wealth of data from aquatic species indicates reproductive effects of MNPs. The first studies in rodent models demonstrate that MNPs reach the gonads after oral exposure and may impact offspring after maternal exposure during the gestational period. These effects may arise from the particles themselves or the presence of plastic contaminants that leach from plastics. Plastic contamination has been detected in human placentas, fetal fluid and the meconium of newborns, indicating the presence of plastics from the very first start of life. Currently there is a lack of studies that investigate the impact of MNP exposure during the periconception and embryonic period, whereas this is an extremely sensitive period that needs considerable attention with the growing amount of plastics in our environment.

Effects of nano and microplastics on the reproduction system: In vitro and in vivo studies review

Microplastics (MPs) and nanoplastics (NPs), as their name suggest, are tiny plastic particles. The negative impact of MPs as an emerging pollutant on humans is not hidden from anyone. Recent research on how this pollutant affects the reproductive system and how it enters the blood, placenta, and semen has attracted the attention of scientists. This review study deals with the reproductive toxicity of MPs particles in terrestrial animals, aquatic animals, soil fauna, human cells, and human placenta. In vitro and in vivo animal studies showed that MPs can lead to reduced fertility in men, reduced ovarian capacity, apoptosis of granulosa cells, or even reduced sperm motility. They cause oxidative stress and cell apoptosis and inflammatory effects. The results of these animal studies show that MPs may have similar effects on the human reproductive system. However, not much research has been done on human reproductive toxicity by MPs. Therefore, special attention should be paid to the toxicity of the reproductive system by MPs. The purpose of this comprehensive study is to express the importance of the impact of MPs on the reproductive system. These results provide new insight into the potential dangers of MPs.

Reproductive toxicity of microplastics in female mice and their offspring from induction of oxidative stress

Microplastics (MPs) are an emerging pollutant that is becoming recognized as an increasingly serious environmental problem. The biological toxicity and resulting health risks of MPs have attracted much attention in the research community. While the effects of MPs on various mammalian organ systems have been described, their interactions with oocytes and the underlying mechanism of their activity within the reproductive system have remained ambiguous. Here, we discovered that oral administration of MPs to mice (40 mg/kg per day for 30 days) significantly reduced the oocyte maturation and fertilization rate, embryo development, and fertility. Ingestion of MPs significantly increased the ROS level in oocytes and embryos, leading to oxidative stress, mitochondrial dysfunction, and apoptosis. Moreover, mouse exposure to MPs caused DNA damage in oocytes, including spindle/chromosome morphology defects, and downregulation of actin and Juno expression in mouse oocytes. In addition, mice were also exposed to MPs (40 mg/kg per day) during gestation and lactation to determine trans-generational reproductive toxicity. The results showed that maternal exposure to MPs during pregnancy resulted in a decline in birth and postnatal body weight in offspring mice. Furthermore, MPs exposure of mothers markedly reduced oocyte maturation, fertilization rate, and embryonic development in their female offspring. This investigation provides new insights on the mechanism of MPs' reproductive toxicity and raises concerns for potential risks of MP pollution on the reproductive health of humans and animals.

The ovarian-related effects of polystyrene nanoplastics on human ovarian granulosa cells and female mice

Nanoplastics (NPs) have recently emerged in the context of global plastic pollution. They may be more toxic than macroplastics litter and microplastic fragments due to its abundances, tiny sizes, and cellular accessibility. The female reproductive toxicity of NPs has been widely documented for aquatic animals, but their effects and underlying mechanisms remain poorly understood in mammals. This study aimed to explore the effects of NPs on female reproduction using human ovarian granulosa cells (GCs) and female mice. The accumulation of polystyrene NPs (PS-NPs) in human granulosa-like tumor cells (KGN cells) and the ovaries of female Balb/c mice were evaluated by exposure to fluorescent PS-NPs. Proliferation and apoptosis, reactive oxygen species (ROS), and Hippo signaling pathway-related factors were analyzed in KGN cells. In addition, fertility rate, litter size, ovarian weight and microstructure, follicle development, serum level of anti-Mullerian hormone, and apoptosis in ovaries were examined in female mice. Here, the PS-NPs can penetrate the KGN cells and accumulate in the ovaries. In vitro, 100 μg/ml PS-NPs inhibited proliferation, induced apoptosis, accumulated ROS, activated three key regulators of the Hippo signaling pathway (MST1, LATS1, and YAP1), and downregulated the mRNA levels of CTGF and Cyr61 in KGN cells. Furthermore, salidroside, an antioxidative compound extracted from Rhodiola rosea, alleviated the damage of PS-NPs to KGN and inhibited the activation of the Hippo signal pathway. In vivo, exposure to 1 mg/day PS-NPs resulted in decreased fertility, abnormal ovarian function, and increased ovarian apoptosis in female mice. Overall, our data suggest that PS-NPs cause granulosa cell apoptosis and affect ovarian functions, leading to reduced fertility in female mice, by inducing oxidative stress and dysregulating the Hippo pathway.

Influencing factors for microplastic intake in abundant deep-sea lanternfishes (Myctophidae)

Plastic debris is ubiquitous in the hydrosphere. Yet, we lack an understanding of contamination among deep-sea species and primarily how each trait can influence microplastic intake. We investigated microplastic contamination in the digestive tract of hyper-abundant mesopelagic lanternfishes (n = 364 individuals) from the Southwestern Tropical Atlantic, captured from 90 to 1000 m depth. Overall, microplastics were detected in most individuals analysed (frequency of occurrence = 68 %). Large microplastics, mostly of a filamentous shape were the most frequent, followed by smaller fragments and foams. Microplastics made of high-density polymers (PET, PVC, PA, SBR rubber) were more prevalent than low-density ones (PE, EVA and PBD rubber), especially under deeper layers. Larger microplastics were detected in lanternfishes captured off the northeastern Brazilian coast (mean 0.88 ± SE 0.06 mm) compared to those from around the Rocas Atoll and Fernando de Noronha Archipelago (0.70 ± 0.07 mm; p≤ 0.05), ∼350 km from the continent. Moreover, lanternfishes that migrate from the upper mesopelagic (200-500 m) to the epipelagic layers (<200 m) had simultaneously the highest intake and the smallest particles (1.65 ± 0.17 particles individual^-1 and 0.55 ± 0.07 mm; p≤ 0.05). Biological mediated transport of microplastics from the epipelagic to the mesopelagic waters was evinced, but fishes foraging in shallower layers had the lowest intake (1.11 ± 0.10 part. ind.^-1; p≤ 0.05). Furthermore, the jaw length was positively associated with an increment in microplastic intake (Incidence Rate Ratio = 1.1; p≤ 0.05). The lanternfishes that preferably prey upon fish larvae are more prone to microplastic intake than their counterparts, which forage mostly on crustaceans and gelatinous zooplankton (p≤ 0.05).

Endocrine disrupting effect and reproductive toxicity of the separate exposure and co-exposure of nano-polystyrene and diethylstilbestrol to zebrafish

The co-occurrence of nanoplastics and other pollutants in the environment has gotten a lot of attention, but information on the biological toxicity of their co-exposure was limited. This study aims to reveal the endocrine disrupting effect and reproductive toxicity of nano-polystyrene (NPS) and diethylstilbestrol (DES) to zebrafish under separate and combined exposure. Results indicated that NPS and DES exposure in isolation reduced the hepatosomatic index and gonadosomatic index, and altered the cell maturity in gonads in both cases. Even worse, the co-exposure of NPS and DES exacerbated the damage to the liver and gonads of fish. The two pollutants individually inhibited the secretion of sex hormones and vitellogenin. The inhibition effect of DES was especially dose-dependent, while NPS had weaker effect than DES. Their combined action on the secretion of sex hormones and vitellogenin exhibited additive effect. However, NPS did not affect the content of thyroid hormones in fish, and also had no significant effect on the reduction of thyroid hormone caused by DES exposure. Furthermore, their co-exposure decreased the cumulative eggs from 1031 to 306, and the spawning number from 12 to 8. The fertilization rate and hatchability rete of eggs were reduced by 30.9% and 40.4%, respectively. The abnormality rate of embryos was 65.0%, significantly higher than in separate DES and NPS groups (55.7% and 30.8% respectively). The abnormal development of offspring was mainly pericardial cyst, spinal curvature, and growth retardation.

Microplastics from agricultural plastic mulch films: A mini-review of their impacts on the animal reproductive system

Plastic mulch films (PMFs) are widely used to improve crop quality and quantity. Although they provide a range of benefits, they degrade into widespread microplastics (MPs), which can cause an unavoidable risk of environmental problems. The residue of PMFs is a significant source of MPs in soils, which can then spread into various ecosystems and be easily absorbed by organisms due to their small size, and subsequently transported through food chain. Notably, MPs have been found in the human placenta, stool and blood, raising an urgent reminder of the potential dangers of MPs to human health. This review summarizes recent studies concerning the effects of MPs on the reproductive system in soil invertebrates, aquatic animals and rodents of both sexes and the mechanisms by which MPs affect the animal reproductive system. The studies on females demonstrated that MPs decrease oocyte quantity and quality, and induce ovary fibrosis, pyroptosis and apoptosis of granulosa cells. In addition, disrupted integrity of the blood-testis barrier, damaged spermatogenesis and compromised sperm quality have been shown in most studies on male animals. The studies on the mechanisms of these effects have provided evidence that MPs act on the animal reproductive system through reactive oxygen species-related mechanisms by initiating the Wnt/β-Catenin and NLRP3/Caspase-1 pathways in females, and the Nrf2/HO-1/NF-κB, p38 MAPK and MAPK/Nrf2 pathways in males. Taken together, these studies reveal the reproductive toxicity of MPs from PMF on animals and serve as a reminder to properly dispose of PMF waste.