Mitigative effects of zinc on cadmium-induced reproductive toxicity in the male freshwater crab Sinopotamon henanense

Zinc mitigates cadmium-induced sperm dysfunction through regulating Ca2+ and metallothionein expression in the freshwater crab Sinopotamon henanense

Cadmium (Cd) is a highly toxic heavy metal element that might adversely affect sperm function such as the acrosome reaction (AR). Although it is widely recognized that zinc (Zn) plays a crucial role in sperm quality, the complete elucidation of how Zn ameliorates Cd-induced sperm dysfunction is still unclear. In this study, we aimed to explore the protective effects of Zn against the sperm dysfunction induced by Cd in the freshwater crab Sinopotamon henanense. The results demonstrated that Cd exposure not only impaired the sperm ultrastructure, but also caused sperm dysfunction by decreasing the AR induction rate, acrosome enzyme activity, and Ca2+ content in sperm while elevating the activity and transcription expression of key Ca2+ signaling pathway-related proteins Calmodulin (CAM) and Ca2+-ATPase. However, the administration of Zn was found to alleviate Cd-induced sperm morphological and functional disorders by increasing the activity and transcription levels of CaM and Ca2+-ATPase, thereby regulating intracellular Ca2+ homeostasis and reversing the decrease in Ca2+ contents caused by Cd. Furthermore, this study was the first to investigate the distribution of metallothionein (MT) in the AR of S. henanense, and it was found that Zn can reduce the elevated levels of MT in crabs caused by Cd, demonstrating the significance of Zn in inducing MT to participate in the AR process and in metal detoxification in S. henanense. These findings offer novel perspectives and substantiation regarding the utilization of Zn as a protective agent against Cd-induced toxicity and hold significant practical implications for mitigating Cd-induced sperm dysfunction.

Isolation, cloning, and tissue distribution and functional analysis of ShP-glycoprotein in the freshwater crab Sinopotamon henanense exposed to Cd and Cd-QDs

P-glycoprotein (Pgp), a member of ATP binding cassette (ABC) transporter family, can extrude toxic substances out of cells by mediating multi-xenobiotic resistance (MXR) in aquatic organisms, however, its regulation and association with MXR are still unclear. In this work, the genetic information of Pgp in freshwater crab Sinopotamon henanense (ShPgp) was revealed for the first time. ShPgp with a total of 4488 bp was cloned and analyzed, which includes 4044 bp open reading frame, 353 bp 3' untranslated region, and 91 bp 5' untranslated region. The recombinant ShPGP were expressed in Saccharomyces cerevisiae and taken for SDS-PAGE and western blot analysis. ShPGP was widely expressed in the midgut, hepatopancreas, testis, ovary, gill, hemocytes, accessory gonad and myocardium of the crabs studied. The images of immunohistochemistry indicated that ShPgp was mainly distributed in the cytoplasm and cell membrane. When the crabs were exposed to cadmium or cadmium containing quantum dots (Cd-QDs), not only the relative expression of ShPgp mRNA and the protein produced were enhanced, but also the MXR activity and ATP contents. The relative expression of target genes related to energy metabolism, detoxification and apoptosis was also determined in the carbs exposed to Cd or Cd-QDs. The results showed that bcl-2 was significantly down-regulated, while other genes were up-regulated except PPAR (not affected). However, when the Shpgp in treated crabs was interfering by knockdown technique, their apoptosis and the expression of proteolytic enzyme genes and transcription factors MTF1 and HSF1 were also elevated, while the expression of apoptosis inhibiting and fat metabolism genes were compromised. Based on the observation, we concluded that MTF1 and HSF1 were involved in gene transcription regulation of mt and MXR, respectively, while PPAR had limited regulatory effect on those genes in S. henanense. NF-κB may play a negligible role in the process of apoptosis in testes induced by cadmium or Cd-QDs. However, the detail information regarding Pgp involvement in SOD or MT, and its association with apoptosis during xenobiotics insults remain to be explored.

Zinc alleviates cadmium-induced reproductive toxicity via regulating ion homeostasis, metallothionein expression, and inhibiting mitochondria-mediated apoptosis in the freshwater crab Sinopotamon henanense

Cadmium (Cd) is a carcinogenic environmental pollutant that harms male reproductive systems by lowering sperm quality, impairing spermatogenesis, and causing apoptosis. Although zinc (Zn) has been reported to alleviate Cd toxicity, the underlying mechanisms have not been fully elucidated. The aim of this work was to investigate the mitigating effects of Zn on Cd-induced male reproductive toxicity in the freshwater crab Sinopotamon henanense. Cd exposure not only resulted in its accumulation but also in Zn deficiency, decreased sperm survival rate, poor sperm quality, altered ultrastructure, and increased apoptosis in the testis of the crabs. Morever, Cd exposure increased the expression and distribution of metallothionein (MT) in the testis. However, Zn supplementation effectively mitigated the aforementioned effects of Cd, as demonstrated by preventing Cd accumulation, increasing Zn bioavailability, alleviating apoptosis, increasing mitochondrial membrane potential, decreasing reactive oxygen species (ROS) levels, and restoring MT distribution. Moreover, Zn also significantly reduced the expression of apoptosis-related (p53, Bax, CytC, Apaf-1, Caspase-9, Caspase-3), metal transporter-related ZnT1, metal-responsive transcription factor 1 (MTF1), and the gene and protein expression of MT, while increasing the expression of ZIP1 and Bcl-2 in the testis of Cd-treated crabs. In conclusion, Zn alleviates Cd-induced reproductive toxicity via regulating ion homeostasis, MT expression, and inhibiting mitochondria-mediated apoptosis in the testis of S. henanense. The information obtained in this study may serve as the foundation for further investigation into the development of mitigation strategies for adverse ecological and human health outcomes associated with Cd contamination or poisoning.

Heavy metals and metalloid in aquatic invertebrates: A review of single/mixed forms, combination with other pollutants, and environmental factors

Heavy metals (HMs) and metalloid occur naturally and are found throughout the Earth's crust but they are discharged into aquatic environments at high concentrations by human activities, increasing heavy metal pollution. HMs can bioaccumulate in higher organisms through the food web and consequently affect humans. In an aquatic environment, various HMs mixtures can be present. Furthermore, HMs adsorb on other environmental pollutants, such as microplastics and persistent organic pollutants, causing a synergistic or antagonistic effect on aquatic organisms. Therefore, to understand the biological and physiological effects of HMs on aquatic organisms, it is important to evaluate the effects of exposure to combinations of complex HM mixtures and/or pollutants and other environmental factors. Aquatic invertebrates occupy an important niche in the aquatic food chain as the main energy link between higher and lower organisms. The distribution of heavy metals and the resulting toxic effects in aquatic invertebrates have been extensively studied, but few reports have dealt with the relationship between HMs, pollutants, and environmental factors in biological systems with regard to biological availability and toxicity. This review describes the overall properties of individual HM and their effects on aquatic invertebrates and comprehensively reviews physiological and biochemical endpoints in aquatic invertebrates depending on interactions among HMs, other pollutants, and environmental factors.

Toxicological mechanism of cadmium in the clam Ruditapes philippinarum using combined ionomic, metabolomic and transcriptomic analyses

Cadmium (Cd) contamination in marine environment poses great risks to the organisms due to its potential adverse effects. In the present study, the toxicological effects and mechanisms of Cd at environmentally relevant concentrations (5 and 50 μg/L) on clam Ruditapes philippinarum after 21 days were investigated by combined ionomic, metabolomic, and transcriptomic analyses. Results showed that the uptake of Cd significantly decreased the concentrations of Cu, Zn, Sr, Se, and Mo in the whole soft tissue from 50 μg/L Cd-treated clams. Significantly negative correlations were observed between Cd and essential elements (Zn, Sr, Se, and Mo). Altered essential elements homeostasis was associated with the gene regulation of transport and detoxification, including ATP-binding cassette protein subfamily B member 1 (ABCB1) and metallothioneins (MT). The crucial contribution of Se to Cd detoxification was also found in clams. Additionally, gene set enrichment analysis showed that Cd could interfere with proteolysis by peptidases and decrease the translation efficiency at 50 μg/L. Cd inhibited lipid metabolism in clams and increased energy demand by up-regulating glycolysis and TCA cycle. Osmotic pressure was regulated by free amino acids, including alanine, glutamate, taurine, and homarine. Meanwhile, significant alterations of some differentially expressed genes, such as dopamine-β-hydroxylase (DBH), neuroligin (NLGN), NOTCH 1, and chondroitin sulfate proteoglycan 1 (CSPG1) were observed in clams, which implied potential interference with synaptic transmission. Overall, through integrating multiple omics, this study provided new insights into the toxicological mechanisms of Cd, particularly in those mediated by dysregulation of essential element homeostasis.

A novel type II crustin in the innate immune response of the freshwater crab (Sinopotamon henanense) against infection and its expression changes by cadmium

Antibacterial peptide (AMP), an effector of the innate immune system, is an essential component of invertebrate innate immunity. Crustin is a family of antimicrobial peptides that are widely studied in crustaceans. Here we report a novel crustin (designated Shcrustin) from the freshwater crab Sinopotamon henanense. The results revealed that the full-length cDNA of Shcrustin was 691 bp with an open reading frame (ORF) of 510 bp. Phylogenetic analysis of the Shcrustin sequence showed that it clustered with type II crustin. Shcrustin exists in different tissues, among which the highest expression level is found in the gills. After the bacterial challenge, the expression of Shcrustin increased in hemocytes or gills. However, crustin expression was suppressed in the presence of cadmium (Cd). To elucidate the biological activity of Shcrustin, we constructed a recombinant Shcrustin protein. Purified rShcrustin could bind to a variety of bacteria and inhibit the growth of different bacteria indicating that Shcrustin has inhibitory activity against gram-positive and gram-negative bacteria. In addition, the phagocytic rate of hemocytes toward bacteria decreased after the interference of Shcrustin expression by RNA interference, suggesting that Shcrustin may be involved in such a process. Therefore, we conclude that Shcrustin may be involved in the innate immunity of S. henanense by binding to bacteria and promoting hemolymph phagocytosis to clear invading pathogens. It is an important immune effector against pathogen infection. In the presence of Cd, it may alter the expression of Shcrustin and suppress its immune function.

Cadmium: A Focus on the Brown Crab (Cancer pagurus) Industry and Potential Human Health Risks

Cadmium is a major health risk globally and is usually associated with pollution and anthropogenic activity. The presence of cadmium in food is monitored to ensure that the health and safety of consumers are maintained. Cadmium is ubiquitous in the Asian and Western diets, with the highest levels present in grains, leafy greens, and shellfish. As part of their natural lifecycle of moulting and shell renewal, all crustaceans-including the brown crab (Cancer pagurus)-bioaccumulate cadmium from their environment in their hepatopancreas. The brown crab is an important species to the crab-fishing industries of many European countries, including Ireland. However, the industry has come under scrutiny in Europe due to the presence of cadmium in the brown crab meat intended for live export to Asia. This review explores evidence regarding the effects of cadmium consumption on human health, with a focus on the brown crab. Differences in cadmium surveillance have given rise to issues in the crab industry, with economic consequences for multiple countries. Currently, evidence suggests that brown crab consumption is safe for humans in moderation, but individuals who consume diets characterised by high levels of cadmium from multiple food groups should be mindful of their dietary choices.

Curative Potential of Substances with Bioactive Properties to Alleviate Cd Toxicity: A Review

Rapid urbanization and industrialization have led to alarming cadmium (Cd) pollution. Cd is a toxic heavy metal without any known physiological function in the organism, leading to severe health threat to the population. Cd has a long half-life (10-30 years) and thus it represents serious concern as it to a great extent accumulates in organs or organelles where it often causes irreversible damage. Moreover, Cd contamination might further lead to certain carcinogenic and non-carcinogenic health risks. Therefore, its negative effect on population health has to be minimalized. As Cd is able to enter the body through the air, water, soil, and food chain one possible way to defend and eliminate Cd toxicities is via dietary supplements that aim to eliminate the adverse effects of Cd to the organism. Naturally occurring bioactive compounds in food or medicinal plants with beneficial, mostly antioxidant, anti-inflammatory, anti-aging, or anti-tumorigenesis impact on the organism, have been described to mitigate the negative effect of various contaminants and pollutants, including Cd. This study summarizes the curative effect of recently studied bioactive substances and mineral elements capable to alleviate the negative impact of Cd on various model systems, supposing that not only the Cd-derived health threat can be reduced, but also prevention and control of Cd toxicity and elimination of Cd contamination can be achieved in the future.

Ameliorating effect of the biological Zinc nanoparticles in abamectin induced hepato-renal injury in a rat model: Implication of oxidative stress, biochemical markers and COX-2 signaling pathways

Extensive use of abamectin (ABM) as an anthelmintic in veterinary systems adversely affects the health and welfare of animals and humans. Zinc nanoparticles (ZnNPs) have therapeutic benefits and ameliorate the effect of environmental pollutants. In this study, we assessed the ameliorative effect of ZnNPs against the sub-lethal toxicity of ABM in rats. Forty healthy rats were randomly selected into four groups (n = 10); the control received normal saline and test rats were treated orally twice weekly with ABM (1 mg/kg bwt), ZnNPs (10 mg/kg bwt) and ABM + ZnNPs for 28 days. Upon completion of the study period, blood and tissue samples were collected and prepared for hematological, biochemical, pathological, and immunohistochemical analysis. Our results showed that ABM treatment significantly decreased body weight gain (BWG), red blood cells (RBCs), hemoglobin (Hb), hematocrit (HC), and platelet (PLT); while it significantly increased white blood cells (WBCs) and lymphocytes. ABM also significantly decreased antioxidant enzyme activities: superoxide dismuthase (SOD), glutathione peroxidase (GPx), and catalase (CAT) and increased hydrogen peroxide and malondialdehyde levels compared with other groups. ABM significantly raised alanine aminotransferase (ALT), aspartate amino transaminase (AST), and alkaline phosphatase (ALP) levels, which was restored by co-administration of ZnNPs. Moreover, ZnNPs ameliorated ABM-mediated negative histopathological changes in the liver and kidney tissues, exhibiting a significant protective effect. Cyclooxygenase 2 (COX-2) + immuno-expression were reduced after pretreatment with ZnNPs. These findings suggested that co-administration of ZnNPs with ABM mitigated its toxicity by combating oxidative stress and boosting antioxidant capacity, indicating the efficacy of ZnNPs in attenuating ABM toxicity.

Impacts of cadmium on male fertility: Lessons learnt so far

Cadmium (Cd) is one of the most dangerous heavy metals in the world. Globally, toxicities associated with cadmium and its attendant negative impact on humans and animals cannot be under-estimated. Cd is a heavy metal, and people are exposed to it through contaminated foods and smoking. Cd exerts its deleterious impacts on the testes (male reproductive system) by inducing oxidative stress, spermatogenic cells apoptosis, testicular inflammation, decreasing androgenic and sperm cell functions, disrupting ionic homeostasis, pathways and epigenetic gene regulation, damaging vascular endothelium and blood testes barrier. In association with other industrial by-products, Cd has been incriminated for the recent decline of male fertility rate seen in both man and animals. Understanding the processes involved in Cd-induced testicular toxicity is vital for the innovation of techniques that will help ameliorate infertility in males. In this review, we summed up recent studies on the processes of testicular toxicity and male infertility due to Cd exposure. Also, the usage of different compounds including phytochemicals, and plant extracts to manage Cd reprotoxicity will be reviewed.

Toxicological responses of juvenile Chinese shrimp Fenneropenaeus chinensis and swimming crab Portunus trituberculatus exposed to cadmium

Cadmium (Cd) is one of the typical metal pollutants in the Bohai Sea. To evaluate the acute toxicological effects of Cd on marine crustaceans, juvenile Fenneropenaeus chinensis and Portunus trituberculatus were exposed to Cd at environmentally relevant concentrations (5 and 50 μg/L) for 96 h. Cd accumulation, antioxidants and metabolite profiles were characterized to elucidate the responses of juvenile crustaceans to Cd stress. Significant Cd accumulation was observed in both juvenile crustaceans in 50 μg/L Cd-treated group. Results showed that Cd exposure induced hormesis based on the alterations of GSH, SOD and CAT activities (i.e. increased levels in the low concentration of Cd treatment and recovered levels in the high concentration of Cd treatment) in juvenile P. trituberculatus. Similarly, the responses of GSH contents presented hormesis pattern in Cd-treated juvenile F. chinensis. Na+-K+-ATPase contents were significantly elevated in 50 μg/L Cd-treated group. In addition, untargeted NMR-based metabolomics indicated Cd caused the disturbance in osmotic regulation and energy consumption in both juvenile F. chinensis and P. trituberculatus via different pathways. The immunotoxicity and movement disorder were uniquely demonstrated in juvenile P. trituberculatus after Cd exposure.

Multigenerational study of life history traits, bioaccumulation, and molecular responses of Pseudodiaptomus annandalei to cadmium

Metal pollution provide a substantial challenge for environmental health. This study investigated the multigeneration effects of cadmium on populations of the copepod species Pseudodiaptomus annandalei, exposed to a sublethal concentration, 40 µg/L of cadmium (Cd), over 10 generations. At the end of each generation, copepod individuals were collected to estimate fecundity, bioaccumulation, and real time qPCR quantification of selected differentially expressed genes to evaluate Cd effects and sex-specific responses of copepods across multiple generations. Our results revealed a sex-specific accumulation of Cd integrating 10 successive generations. The concentration of Cd was significantly higher (p < 0.05) in males than in females. We also observed a generational increase in Cd accumulation. Fecundity increased, with the exception of the first generation, possibly as a compensation for a decrease of copepod population size under Cd exposure. Protein expression of copepods exposed to Cd occurred in a sex-specific manner. Hemerythrin was mostly up-regulated in both copepod sexes exposed to Cd with males having the highest expression levels, while heat shock protein 70 was mostly up-regulated in males and down-regulated in female copepods, both exposed to Cd. Although copepods are known to develop adaptive mechanisms to tolerate toxic chemicals, continuous exposure to metals could lead to the bioaccumulation of metals in their offspring through maternal transfer and direct uptake from the medium over several generations. As a consequence, increased metal concentrations in copepods could result in physiological damage, reducing their fitness, and possibly compromise copepod population structures. This study showed that mortality, life history traits and molecular responses of a copepod species provided important toxicological endpoints and bio-markers for environmental risk assessments. Environmental pressure resulting from continuous exposure to persistent pollutants like Cd, could have evolutionary significance. The tendency for copepods to selectively adapt to a toxic environment through modifications, could increase their chance of survival over a long term.

Efficacy and side effects of bio-fabricated sardine fish scale silver nanoparticles against malarial vector Anopheles stephensi

Mosquitoes are a great menace for humankind since they transmit pathogenic organisms causing Malaria, Dengue, Chikungunya, Elephantiasis and Japanese encephalitis. There is an urgent need to discover new and novel biological tools to mitigate mosquito-borne diseases. To develop bioinsecticides through newly developed nanotechnology is another option in the present research scenario. In this study we synthesize and characterize sardine fish scales with silver nitrate by adopting various instrumental techniques such as UV- and FTIR-spectroscopy, energy-dispersive X-ray (EDAX), X-ray diffraction analyses (XRD) and scanning electron microscopy (SEM). Toxicity bioassays were conducted with young developmental stages of mosquito vectors. Significant mortality appeared after different life stages of mosquito vectors (young larval and pupal instars were exposed to the nanomaterials). LC50 values were 13.261 ppm for young first instar larvae and 32.182 ppm for pupae. Feeding and predatory potential of G. affinis, before and after exposure to nanoparticles against mosquito larval (I & II) instars of the mosquitoes showed promising results in laboratory experiments. Feeding potential of mosquito fish without nanoparticle treatment was 79.7% and 70.55% for the first and second instar larval populations respectively. At the nanoparticle-exposed situation the predatory efficiency of mosquitofish was 94.15% and 84.3%, respectively. Antioxidant enzymes like (SOD), (CAT), and (LPO) were estimated in the gill region of sardine fish in control and experimental waters. A significant reduction of egg hatchability was evident after nanoparticle application. It became evident from this study that the nano-fabricated materials provide suitable tools to control the malaria vector Anopheles stephensi in the aquatic phase of its life cycle. This finding suggests an effective novel approach to mosquito control.

Cr(VI) promotes tight joint and oxidative damage by activating the Nrf2/ROS/Notch1 axis

This study aimed to investigate whether Cr(VI) induced tight joint and oxidative damage in the small intestine, as mediated by the nuclear factor erythroid 2-related factor 2 (Nrf2)/reactive oxygen species (ROS)/Notch1 axis crosstalk. Thirty-two ICR mice were obtained and subjected to Cr(VI) via intragastric administration daily for 5 days. Western blot (WB) analysis, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC) staining, and immunofluorescence (IF) staining were applied to detect small intestinal damage, Nrf2, Notch1, and respective downstream targets in this research. Results showed that Cr(VI) led to the tight joint and oxidative damage in the small intestine of mice. Nrf2 was stimulated, and Notch1 (Notch intracellular domain, NICD1) was activated to translocate into the nucleus and activate an antioxidant action. These findings were validated by WB analysis and IF staining. ROS levels increased as the Cr(VI) concentration increased. The colocalization analysis of Nrf2 and NICD1 implied that a crosstalk between Nrf2 and Notch1 existed. Therefore, this study indicated that the Nrf2/ROS/Notch1 axis crosstalk could aggravate the tight joint and oxidative damage in the small intestine after Cr(VI) treatment.