Effects of zinc oxide nanoparticles and zinc sulfate on the testis of common carp, Cyprinus carpio

Cloning and expression profiling of peptide YY in the brain of common carp, Cyprinus carpio

Peptide YY (PYY) is an anorectic brain-gut pancreatic peptide that helps in feeding regulation by reducing appetite and is well characterized in mammals. The role of PYY in relation to brain is least studied in mammals as well as in lower vertebrates including fish, however high expression was evident in male reproductive tissue. In this regard, this study attempts to evaluate the significance of PYY in the brain of common carp, Cyprinus carpio. As a first step, the cDNA of PYY from brain of adult male carp was cloned. Following which expression analysis was performed using juvenile and adult fish. The differential distribution pattern in various regions of brain and ontogeny expression analysis indicated that PYY may involve in physiological processes related to brain-pituitary axis. In addition, a significant decrease in neuropeptide Y expression was observed upon PYY- endoribonuclease-prepared small interfering RNA transfection in brain cells, in vitro indicating plausible PYY-NPY interaction in brain-pituitary axis of common carp.

Fe-NPs and Zn-NPs: Advancing Aquaculture Performance Through Nanotechnology

Aquaculture is a growing industry facing several challenges, including disease control, water quality management, and sustainable feed production. One potential solution to these challenges is the use of trace elements such as iron (Fe) and zinc (Zn), either in their conventional form or as nanoparticles (NPs). Aquatic animals need these micronutrients for normal growth, physiological processes, and overall health. In marine species, iron boosts development, immunity, and disease resistance. At the same time, zinc enhances metabolism, synthesizes essential enzymes, and produces hormones that play a part in defenses, growth, reproduction, and antioxidative activities. According to this review, species-specific requirements by different Fe and Zn compounds have all emphasized the impacts on animal growth and development, antioxidant capacity, reproductive efficiency, and immunological response. However, NPs of Fe and Zn have been found to have higher bioavailability and efficacy than conventional forms. This work examines the effects of applications of Fe and Fe nanoparticles (Fe-NPs) and Zn and Zn nanoparticles (Zn-NPs) in aquaculture. However, the source of Fe and Zn in aquaculture species and administration volume may significantly impact efficacy. Nanotechnology boosts the positive benefits of Fe and Zn by converting them to their nanoforms (Fe-NPs) and (Zn-NPs), which are better used by animals and have a broader intake range. As a result, Fe-NPs and Zn-NPs offer an effective method for using nutrients in aquaculture.

Exposure to copper nanoparticles or copper sulfate dysregulated the hypothalamic-pituitary-gonadalaxis, gonadal histology, and metabolites in Pelteobagrus fulvidraco

This study evaluated the effects of chronic exposure to copper nanoparticles (Cu-NPs) and waterborne copper (CuSO₄) on the reproductive system of yellow catfish (Pelteobagrus fulvidraco). Juvenile yellow catfish were exposed to 100 and 200 μg Cu/L Cu-NPs and 100 μg Cu/L CuSO₄ for 42 days. The results showed clear reproductive defects in both female and male yellow catfish in the 200 μg Cu/L Cu-NPs and 100 μg Cu/L CuSO₄ groups. Exposure to Cu-NPs or CuSO₄ inhibited folliculogenesis and vitellogenesis in the ovaries, and spermatogenesis in the testes, accompanied by elevation of the apoptotic signal. Ultrastructural observations also revealed damaged organelles of gonadal cells in both testes and ovaries. Most of the hypothalamic-pituitary-gonadal (HPG) axis genes examined and serum sex steroid hormones tended to be downregulated after Cu exposure. Metabolomic analysis suggested that gonadal estradiol level is sensitive to Cu-NPs or CuSO₄. The heat map of gonadal metabolomics suggested a similar effect of 200 μg Cu/L Cu-NPs and 100 μg Cu/L CuSO4 in both the ovaries and testes. Additionally, metabolomics data showed that the reproductive toxicity due to Cu-NPs and CuSO₄ may occur via different metabolic pathways. Cu-NPs tend to dysregulate the metabolic pathways of sphingolipid and linoleic acid metabolism in the ovary and the biosynthesis of amino acids and pantothenate and CoA in the testis. Overall, these findings revealed the toxicological effects of Cu-NPs and CuSO₄ on the HPG axis and gonadal metabolism in yellow catfish.

Exposure of carbon nanotubes affects testis and brain of common carp

Carbon nanotubes production has been rapidly increasing for many potential applications, however, the environmental impact of this nanomaterial needs to be comprehended. The present work focused on unraveling the effects of single-walled carbon nanotubes (SWCNT) in the common carp, Cyprinus carpio. The physicochemical properties of SWCNT were analyzed with X-ray diffraction, Fourier transforms infra-red, UV-Vis absorption, transmission electron microscopy (TEM), and Raman spectroscopy before testing for exposure impact. The effects of SWCNT, were investigated by exposing to two doses viz., 10 and 50 μg/L, for 7 days in adult common carp, in vivo. Expression of key steroidogenic and transcription factor genes related to testis and brain were downregulated after the treatment. The concomitant decreases in serum testosterone and 11-ketotestosterone levels revealed the impact of SWCNT after exposure. Further, SWCNT exposure induced antioxidant enzymes namely glutathione-S-transferases, superoxide dismutase, and catalase in both testis and brain. Concurrently, histological and TEM analysis of testis revealed structural disarray. In addition, SWCNT treatment, in testicular and brain primary cell cultures decreased cell viability with an increase of reactive oxygen species levels, leading to a significant elevation of apoptotic cells. In line with this, low mitochondrial membrane potential and DNA damage were also observed during post SWCNT treatment. Taken together, transient exposure of SWCNT causes toxic effects and alters testicular and brain function in the common carp. Thus, the discharge of carbon nanotubes poses a greater risk to the aquatic environment warranting regulatory measures.

Long-Term Exposure to the Water of Wadi El-Rayan Lakes Induced Testicular Damage and Endocrine Disruption in Mugil cephalus

This study aimed to investigate the testicular function of Mugil cephalus that inhabit Wadi El-Rayan lakes. Testes of fish inhabiting the upper lake (site 2) and the lower lake (site 3) of Wadi El-Rayan showed significant decreases in gonadosomatic index, high accumulation levels of six metals, and eight organochlorine pesticide residues. Compared to reference fish, high percentages of histological alterations as testicular degeneration, germ cell reduction, testicular inflammation, vacuolization, and loss of tubular arrangement were observed in sites 2 and 3. Moreover, endocrine disruption signs were recorded based on the percentage of ovotestis appearance and the ovotestis severity index values. The maximum defective testicular antioxidant mechanisms were recorded in site 3 as indicated by sharp decreases in catalase, superoxide dismutase, glutathione reduced levels, and high thiobarbituric acid reactive substances. Finally, long-term exposure to Wadi El-Rayan water may impair the reproductive health of fish via testicular oxidative damage and endocrine disruption.

Advances in endocrine toxicity of nanomaterials and mechanism in hormone secretion disorders

The size of nanoparticles is about 1-100 nm. People are exposed to nanoparticles in environmental pollutants from ancient times to the present. With the maturity of nanotechnology in the past two decades, the production of manufactured nanomaterials is rapidly increasing and they are used in a wide range of aerospace, medicine, food, and industrial applications. However, both natural and manufactured nanomaterials have been proved to pose a threat to diverse organs and systems. The endocrine system is critical to maintaining homeostasis. Endocrine disorders are associated with many diseases, including cancer, reduced fertility, and metabolic diseases. Therefore, we review the literatures dealing with the endocrine toxicity of nanomaterial. This review provides an exhaustive description of toxic effects of several common nanomaterials in the endocrine system; more involved are reproductive endocrinology. Then physicochemical factors that determine the endocrine toxicity of nanomaterials are discussed. Furthermore, oxidative stress, changes in steroid production and metabolic enzymes, organelle disruption, and alterations in signal pathways are introduced as potential mechanisms that may cause changes in hormone levels. Finally, we suggest that a risk assessment of endocrine toxicity based on standard procedures and consideration of endocrine disrupting effects of nanomaterials in the field and its environmental and population effects could be future research directions for endocrine toxicity of nanomaterials.

Fabrication of nano-decorated ZnO-fibrillar chitosan exhibiting a superior performance as a promising replacement for conventional ZnO

In this research, bioactive nano-hybrids based on the nano-fibrillar chitosan-ZnO (NF-CS-ZnO) were synthesized to diminish the toxicity of ZnO-NPs. The successful formation of nano-hybrids was confirmed by FT-IR, UV-Vis, and FE-SEM analyses, showing a uniform spherical ZnO-NPs with an average diameter of 20-30 nm, homogeneously dispersed on NF-CS. The obtained results demonstrated a remarkable antibacterial activity of NF-CS-ZnO-0.6 nano-hybrid against E. coli and S. aureus and, interestingly, no cytotoxic on normal cells (even at a high concentration of 100 μg/mL). Furthermore, NF-CS hybridization efficiently decreased the up-regulation in Cas3, Cas9, and Il6 of inspected fishes compared to the ZnO-NPs. Histopathological examination revealed hepatocyte necrosis in the fish exposed to ZnO-NPs and hyperemia exposed to NF-CS-ZnO-0.6 nano-hybrid. Finally, NF-CS efficiently improved the bio-safety and bactericidal activity of ZnO-NPs; therefore, NF-CS-ZnO nano-hybrid is prominently recommended as a talented low-toxicity antibacterial agent replacement of conventional ZnO-NPs for use in different applications.

Changes of Gene Expression Patterns from Aquatic Organisms Exposed to Metal Nanoparticles

Metal nanoparticles are used in various branches of industry due to their physicochemical properties. However, with intensive use, most of the waste and by-products from industries and household items, and from weathering of products containing nanoparticles, end up in the waters. These pollutants pose a risk to aquatic organisms, one of which is a change in the expression of various genes. Most of the data that focus on metal nanoparticles and their effects on aquatic organisms are about copper and silver nanoparticles, which is due to their popularity in general industry, but information about other nanoparticulate metals can also be found. This review aims to evaluate gene expression patterns in aquatic organisms by metal nanoparticles, specifying details about the transcription changes of singular genes and, if possible, comparing the changes in the expression of the same genes in different organisms. To achieve this goal, available publications tackling this problem are studied and summarized. Nanometals were found to have a modulatory effect on gene expression in different aquatic organisms. Data show both up-regulation and down-regulation of genes. Nano silver, nano copper, and nano zinc show a regulatory effect on genes involved in inflammation and apoptosis, cell cycle regulation and ROS defense as well as in general stress response and have a negative effect on the expression of genes involved in development. Nano gold, nano titanium, nano zinc, and nano iron tend to elevate the transcripts of genes involved in response to ROS, but also pro-apoptotic genes and down-regulate DNA repair-involved genes and anti-apoptotic-involved genes. Nano selenium showed a rare effect that is protective against harmful effects of other nanoparticles, but also induced up-regulation of stress response genes. This review focuses only on the effects of metal nanoparticles on the expression of various genes of aquatic organisms from different taxonomic groups.

Interactive role of Wnt signaling and Zn in regulating testicular function of the common carp, Cyprinus carpio

Wnt signaling is conserved among all species and plays a significant role in various cellular processes including reproduction. The present study identified significant involvement of wnt4a, wnt5b, and wnt8a signaling in the testicular growth of common carp,Cyprinus carpio. Predominant expression of wnt4a, wnt5b, and wnt8a was found in the gonads and Wnt4a was localized in spermatocytes and interstitial cells. Ontogeny and testicular phase-wise analysis signified the importance of wnt isofoms analyzed in this study. Specific pathway activation of Wnt signaling revealed that Wnt4a and Wnt5b act through non-canonical while Wnt8a prefers the canonical pathway. The Wnt signaling regulates several steroidogenic enzyme and testis-related genes which was confirmed by the Wnt blockade experiments. Incidentally, zinc (Zn) is an essential trace element involved in the progression of spermatogenesis in teleosts. In adult male carp, a single administration of Zn at different doses elevated the expression of Wnt and Zn transporter genes and a single-dose (30 μg/g body weight [BW]) of Zn treatment elevated steroidogenic enzyme and testis-related genes which coincided with elevated androgens. Conversely, single-dose administration of Zn chelator to the Zn administered (30 μg/g BW) fish reversed the effects emphasizing a prominent role of Zn in the testicular function perhaps through Wnt signaling. Similar effects were observed in the in vitro experiments using the Zn chelator. Bioaccumulation of Zn and histological analysis revealed the importance of Zn in progression of spermatogenesis and sperm motility. Various assays related to cell viability and proliferation exhibited the role of Zn in promoting spermatogenic cell progression. Flow cytometric analysis confirmed Zn-induced elevation of Wnt and Zn transporter genes in germ and supporting cells. Furthermore, the effects of Zn are dose-related in carp. Taken together, it seems wnt4a, wnt5b, and wnt8a play an important role in testis and exposure of Wnt inhibitor, canonical as well as non-canonical activators, and Zn confirmed that Zn regulates Wnt signaling vis-à-vis promoting spermatogenesis in the common carp.

Short time exposure to low concentration of zinc oxide nanoparticles up-regulates self-renewal and spermatogenesis-related gene expression

Extensive application of zinc oxide (ZnO) nanoparticles (NPs) in everyday life results in increased exposure to these NPs. Spermatogonial stem cells (SSCs) guarantee sperm production throughout the male reproductive life by providing a balance between self-renewal and differentiation. We used an in vitro platform to investigate the ZnO NPs effects on SSCs. We successfully synthesized ZnO NPs. In order to investigate these NPs, we isolated SSCs from mouse testes and cultured them in vitro. Our results confirmed the uptake of ZnO NPs by the cultured SSCs. We observed a dose- and time-dependent decrease in SSC viability. Both spherical and nanosheet ZnO NPs had the same cytotoxic effects on the SSCs, irrespective of their shapes. Moreover, we have shown that short time (one day) exposure of SSCs to a low concentration of ZnO NPs (10 μg/mL) promoted expressions of specific genes (Plzf, Gfr α1 and Bcl6b) for SSC self-renewal and differentiation genes (Vasa, Dazl, C-kit and Sycp3) expressed by spermatogonia during spermatogenesis. Our study provides the first insight into ZnO NPs function in SSCs and suggests a new function for ZnO NPs in the male reproductive system. We demonstrated that ZnO NPs might promote spermatogenesis via upregulation of gene expression related to SSC self-renewal and differentiation at low concentrations. Additional research should clarify the possible effect of ZnO NPs on the SSC genome and its effects on human SSCs.

Chronic excessive Zn intake increases the testicular sensitivity to high ambient temperature in Bama miniature pigs

Zinc (Zn) can accumulate in the body of wild animal and human through bio-magnification effects in the food chain to pose chronic toxicity. Male spermatogenesis was sensitive to excessive Zn and elevated temperature. This study aimed to examine whether or not excessive Zn intake caused testicular toxicity and estimate the interaction between Zn and high temperature (HT) in testes of Bama miniature pigs. Six-month-old pigs were pre-fed with or without additional Zn at 1500 mg/kg diet for 30 d and afterward subjected to HT at 40 °C for 5 h daily for 8 consecutive days. Blood samples were collected on d 31 and d 38 and testes were obtained on d 38 immediately after HT exposure. Our data showed both scrotal surface temperature (T) and body surface T increased after 5-h HT exposure (p < 0.05). Pigs fed with additional Zn showed germ cell loss, the decreased testes weight (p < 0.01) and the elevated testicular H₂O₂ level (p < 0.05) as exposed to HT. In additional Zn groups, the autophagosomes or autolysosomes were more frequently observed in the Leydig cells and abnormal acrosomes increased in spermatids. Additional Zn diet increased p62 protein level (p < 0.05), decreased testicular Zn concentration (p < 0.01) and down-regulated the relative mRNA expression of heme oxygenase 1 (p < 0.05). There were significant interactions between T and Zn on testes weight, the relative weight of testes, testosterone concentration on d 31, and the relative mRNA expression of Zn transporters 1 and 2. In conclusion, chronic excessive Zn diet impacted testicular Zn concentration and made the testes more vulnerable to heat, leading to testicular toxicity in Bama miniature pigs.

Analysis of ZnO nanoparticle-induced changes in Oreochromis niloticus behavior as toxicity endpoint

The toxicity of zinc oxide nanoparticles (ZnO NPs) has been investigated in different animal models. However, concentrations tested in most studies are often much higher than the ones potentially identified in the environment. Therefore, such toxicity limits the application of these studies to evaluate ecotoxicological risks posed by these nanopollutants. Thus, the aim of the current study is to evaluate the impacts of ZnO NPs (at environmentally relevant concentrations - 760 μg/L and 76,000 μg/L, for 72 h) on the behavioral responses of Oreochromis niloticus (Nile tilapia) exposed to it. Results did not evidence harmful effects of NPs on animals' locomotor abilities (evaluated through open-field and light-dark transition tests), or anxiety-predictive behavior. On the other hand, Zn bioaccumulation in the body tissues of the analyzed tilapias was correlated to changes in eating behavior (motivated by ration pellets), as well as to deficits in antipredatory defensive behavior (under individual and collective conditions). Tilapia exposed to ZnO NPs recorded lower avoidance, flight and territorialist behavior rates when they were individually confronted with potential predators (Salminus brasiliensis). However, collectively exposed animals were unable to recognize their predators, as well as to differentiate them from artificial baits ("false predators"). The present study is the first to report biological impacts resulting from the short exposure of fish-group representatives to ZnO NPs. Thus, we believe that it may be relevant to improve the knowledge about ecotoxicological risks posed by these pollutants.

Role of Autophagy in Zinc Oxide Nanoparticles-Induced Apoptosis of Mouse LEYDIG Cells

Zinc oxide nanoparticles (ZnO NPs) have shown adverse health impact on the human male reproductive system, with evidence of inducing apoptosis. However, whether or not ZnO NPs could promote autophagy, and the possible role of autophagy in the progress of apoptosis, remain unclear. In the current study, in vitro and in vivo toxicological responses of ZnO NPs were explored by using a mouse model and mouse Leydig cell line. It was found that intragastrical exposure of ZnO NPs to mice for 28 days at the concentrations of 100, 200, and 400 mg/kg/day disrupted the seminiferous epithelium of the testis and decreased the sperm density in the epididymis. Furthermore, serum testosterone levels were markedly reduced. The induction of apoptosis and autophagy in the testis tissues was disclosed by up-regulating the protein levels of cleaved Caspase-8, cleaved Caspase-3, Bax, LC3-II, Atg 5, and Beclin 1, accompanied by down-regulation of Bcl 2. In vitro tests showed that ZnO NPs could induce apoptosis and autophagy with the generation of oxidative stress. Specific inhibition of autophagy pathway significantly decreased the cell viability and up-regulated the apoptosis level in mouse Leydig TM3 cells. In summary, ZnO NPs can induce apoptosis and autophagy via oxidative stress, and autophagy might play a protective role in ZnO NPs-induced apoptosis of mouse Leydig cells.