Effects of metals cadmium and chromium alone and in combination on the liver and kidney tissue of male Spraque-Dawley rats: An ultrastructural and electron-energy-loss spectroscopy investigation

Antagonistic effects of titanium dioxide nanoparticles on cadmium-induced nephrotoxicity and intestinal flora imbalance by reducing its bioavailability in rats

Titanium dioxide nanoparticles (nTiO2) possess unique physicochemical properties, such as large specific surface area, enabling heavy metals adsorption like Cadmium (Cd), yet the combined risks to the ecosystem and human remain unclear. This 90-day study explored the combined effects of nTiO2 (at a population-relevant dose of 100 mg/kg body weight administered via gavage) and cadmium chloride (CdCl2) (50 mg Cd/L by drinking water) on kidney and gut microbiota of rats. Co-exposure of nTiO2 and Cd significantly reduced the nephrotoxicity induced by Cd, with lower levels of urine biochemical indicators and Cd content, milder histopathological changes and ultrastructural damage. A two-way ANOVA analysis suggested antagonism between nTiO2 and Cd on urinary creatinine (CRE) and Urea. Coincidentally, gut microbiota remained unaffected by nTiO2 but was disrupted by Cd. Co-exposure also partially alleviated the adverse changes, restoring the decreased Beta-diversity and the relative abundance of bacteria to control levels. Furthermore, co-exposure resulted in a 19.2 % decline in the blood Cd concentration and an 8.6 % reduction in kidney, while the Cd content of 24 h feces was 3.6 % higher. These findings suggested antagonistic effects of nTiO2 against Cd-induced nephrotoxicity and intestinal flora disorder in rats. The effects might be attributed to the adsorption of nTiO2 on Cd, which resulted in the reduced Cd intake and distribution, coupled with increased excretion, thereby decreasing the Cd bioavailability. This study provides new evidence for understanding the impacts of nTiO2 and Cd on mammals and will contribute to the further risk assessments of co-exposure to human health and environment safety.

Ameliorative effect of aqueous avocado seed extract against chromium-induced oxidative stress and cellular damage in rabbit kidney

The accumulation of chromium in renal tissues promotes the generation of reactive oxygen species (ROS), leading to oxidative stress, genomic and cellular harm, and ultimately necrotic and apoptotic cell death induced by free radicals. Hence, the utilization of antioxidant phytochemicals becomes crucial for cellular defense against oxidative damage. This study endeavors to explore the potential protective effects of an aqueous avocado seed extract (ASE) on rabbit kidneys exposed to chromium-induced damage. Fifteen adult rabbits were distributed into three groups: Group 1 was kept as the control. The second and third groups received a daily dose of K2Cr2O7 (5 mg/kg) intraperitoneally for 2 weeks. While the third group was given an oral dose of ASE (400 mg/kg). In rabbits administered with Cr (VI), kidney homogenates showed a marked increase in Malondialdehyde (MDA) (69.3 ± 4.1 nmol/g) along with a decrease in glutathione (59 ± 5.8 nmol/mg) content and the activity superoxide dismutase (SOD) (0.5 ± 0.05 U/mg protein), glutathione peroxidase (GPx) (16.7 ± 1.1 μmol/mg protein), and catalase (CAT) (73.8 ± 3.9 U/g protein) compared to the levels in control group. Also, the gene expression data for the enzymes SOD, GPx, and CAT dropped dramatically in kidney tissue following Cr (VI) injection. Additionally, Bowman's capsule and glomerulus showed degenerative alterations in the kidney's histopathology and immunohistochemistry. ASE treatment when administered along with Cr (VI) enhanced the activity and gene expression of antioxidant enzymes and improved histopathological conditions. The findings of this study unequivocally show that avocado seed extract, which is rich in phenolic derivatives, is a potent nephroprotective agent that inhibits nephrotoxicity induced by Cr (VI) in rabbits.

Heavy metals and elderly kidney health: A multidimensional study through Enviro-target Mendelian Randomization

Chronic Kidney Disease (CKD), closely linked to environmental factors, poses a significant public health challenge. This study, based on 529 triple-repeated measures from key national environmental pollution area and multiple gene-related public databases, employs various epidemiological and bioinformatics models to assess the impact of combined heavy metal exposure (Chromium [Cr], Cadmium [Cd], and Lead [Pb]) on early renal injury and CKD in the elderly. Introducing the novel Enviro-Target Mendelian Randomization method, our research explores the causal relationship between metals and CKD. The findings indicate a positive correlation between increased levels of metal and renal injury, with combined exposure caused renal damage more significantly than individual exposure. The study reveals that metals primarily influence CKD development through oxidative stress and metal ion resistance pathways, focusing on three related genes (SOD2, MPO, NQO1) and a transcription factor (NFE2L2). Metals were found to regulate oxidative stress levels in the body by increasing the expression of SOD2, MPO, NQO1, and decreasing NFE2L2, leading to CKD onset. Our research establishes a new causal inference framework linking environmental pollutants-pathways-genes-CKD, assessing the impact and mechanisms of metal exposure on CKD. Future studies with more extensive in vitro evidence and larger population are needed to validate.

Complex interplay of heavy metals and renal injury: New perspectives from longitudinal epidemiological evidence

BACKGROUND

Epidemiological studies have reported associations between heavy metals and renal function. However, longitudinal studies are required to further validate these associations and explore the interactive effects of heavy metals on renal function and their directional influence.

METHOD

This study, conducted in Northeast China from 2016 to 2021, included a four-time repeated measures design involving 384 participants (1536 observations). Urinary concentrations of chromium (Cr), cadmium (Cd), manganese (Mn), and lead (Pb) were measured, along with renal biomarkers including urinary microalbumin (umAlb), urinary albumin-to-creatinine ratio (UACR), N-acetyl-β-D-glucosaminidase (NAG), and β2-microglobulin (β2-MG) levels. Estimated glomerular filtration rate (eGFR) was calculated. A Linear Mixed Effects Model (LME) examined the association between individual metal exposure and renal biomarkers. Subsequently, Quantile g-computation and Bayesian Kernel Machine Regression (BKMR) models assessed the overall effects of heavy metal mixtures. Marginal Effect models examined the directional impact of metal interactions in the BKMR on renal function.

RESULT

Results indicate significant impacts of individual and combined exposures of Cr, Cd, Pb, and Mn on renal biomarkers. Metal interactions in the BKMR model were observed, with synergistic effects of Cd-Cr on NAG, umAlb, UACR; Cd-Pb on NAG, UACR; Pb-Cr on umAlb, UACR, eGFR-MDRD, eGFR-EPI; and an antagonistic effect of Mn-Pb-Cr on UACR.

CONCLUSION

Both individual and combined exposures to heavy metals are associated with renal biomarkers, with significant synergistic interactions leading to renal damage. Our findings elucidate potential interactions among these metals, offering valuable insights into the mechanisms linking multiple metal exposures to renal injury.

Adverse neurological effects after exposure to copper, manganese, and mercury mixtures in a Spraque-Dawley rat model: an ultrastructural investigation

Exposure to environmental metal pollutants is linked to oxidative stress and the subsequent development of neurological disease. In this study, the effects of copper, manganese, and mercury, were evaluated at X100 the World Health Organization safety limits for drinking water. Using a Sprague-Dawley rat model, following exposure for 28 days, the effects of these metals on biochemical blood parameters and tissue and cellular structure of the brain were determined. Biochemical analysis revealed no hepatocellular injury with minor changes associated with the hepatobiliary system. Minimal changes were found for renal function and the Na+/K+ ratio was reduced in the copper and manganese (Cu + Mn) and copper, manganese, and mercury (Cu, Mn + Hg) groups that could affect neurological function. Light microscopy of the brain revealed abnormal histopathology of Purkinje cells in the cerebellum and pyramidal cells in the cerebrum as well as tissue damage and fibrosis of the surface blood vessels. Transmission electron microscopy of the cerebral neurons showed microscopic signs of axonal damage, chromatin condensation, the presence of indistinct nucleoli and mitochondrial damage. Together these cellular features suggest the presence and influence of oxidative stress. Exposure to these metals at X100 the safety limits, as part of mixtures, induces changes to neurological tissue that could adversely influence neurological functioning in the central nervous system.

Fagonia indica ameliorates chromium-induced nephrotoxicity: Role of antioxidant activity and pro-inflammatory cytokines in in-vivo renoprotection

Chromium (Cr) is an environmental pollutant, has high redox potential, and can exist in various oxidation states, possibly leading to nephrotoxicity. As a potential treatment option, Fagonia indica (F. indica) is an herb remedy traditionally used as a phytomedicine to cure ailments. However, efficient validation of its protective effect and molecular mechanisms has not yet been established. As such, this study aims to investigate the protective effect of F. indica against Cr-induced nephrotoxicity in Swiss mice. Mice were divided into five groups: group I (negative control), group II (F. indica), group III (potassium dichromate [PDC]-treated), group IV (PDC + saline), and group V (PDC + F. indica). Our results demonstrate that group III exhibited decreases in superoxide dismutase (SOD), glutathione s-transferases (GST), glutathione peroxidase (GSH-Px), catalase (CAT), and thioredoxin peroxidase (TPX) levels. Meanwhile, protein carbonyl (PCO) and malondialdehyde (MDA) levels increased in kidney homogenates, increasing the expression of the pro-inflammatory cytokine interleukin-6 (IL-6). This was followed by elevated NF-κB, blood urea nitrogen (BUN), and creatinine serum levels in group III compared with group I. Moreover, histopathological and immunohistochemical examinations demonstrated severe damage to the renal tubular epithelial cells, as well as marked congestion and expressions of caspase-3 and NF-κB. Further, group V showed an improvement in antioxidant activity parameters and reductions in the IL-6, caspase-3, and NF-κB expressions, followed by significant decreases in NF-κB, BUN, and creatinine serum levels. Furthermore, fewer histopathological disturbances were observed compared with untreated group III. Such alterations may be attributed to the antioxidant and anti-inflammatory effects of F. indica. Therefore, our exploration reveals that F. indica is effective in protecting against Cr-induced nephrotoxicity, and it could be applied in the future to human kidney diseases caused by environmental pollutants.

The recent development of inverse vulcanized polysulfide as an alternative adsorbent for heavy metal removal in wastewater

Inverse vulcanized polysulfides have been used as low-cost and effective adsorbents to remediate heavy metals in wastewater. Inverse vulcanization introduces sustainable polysulfide synthesis by solving the rapid desulfurization problem of unstable polysulfides, and provides superior performance compared to conventional commercial adsorbents. The review discussed the brief applications of the inverse vulcanized polysulfides to remove heavy metal wastewater and emphasized the modified synthesis processes for enhanced uptake ratios. The characteristics of polysulfide adsorbents, which play a vital role during the removal process are highlighted with a proper discussion of the interaction between metal ions and polysulfides. The review paper concludes with remarks on the future outlook of these low-cost adsorbents with high selectivity to heavy metals. These polysulfide adsorbents can be prepared using a wide variety of crosslinker monomers including organic hydrocarbons, cooking oils, and agro-based waste materials. They have shown good surface area and excellent metal-binding capabilities compared to the commercially available adsorbents. Proper postmodification processes have enabled the benefits of repetitive uses of the polysulfide adsorbents. The improved surface area obtained by appropriate choice of crosslinkers, modified synthesis techniques, and regeneration through post-modification has made inverse vulcanized polysulfides capable of removing.

Fagonia indica attenuates chromium-induced nephrotoxicity via antioxidant and anti-inflammatory activities in mice

Chromium (Cr) is a common environmental pollutant that has wide-ranging toxic manifestations. Fagonia indica (F. indica) is an herbal medicine with anti-inflammatory properties and antioxidant activity. This study aims to evaluate the protective role of F. indica (whole plant) in attenuating Cr-induced nephrotoxicity in Swiss mice. Swiss albino mice were divided into five groups (10 mice in each): group I (control); group II (F. indica-treated); group III (Cr-intoxicated); group IV (Cr- and saline-intoxicated); and group V (Cr-intoxicated and F. indica-treated). Blood samples were drawn after sacrifice for biochemical examinations. Kidney specimens were collected to examine antioxidant activities and conduct histological and immunohistochemical studies for all groups. Mice intoxicated with Cr at 15 mg/kg/b.wt showed a decrease in superoxide dismutase (SOD), glutathione S-transferase (GST), and glutathione peroxidase (GSH-Px) levels compared to the control group, followed by an elevation in the serum IL-6 level. The data revealed severe damage to the renal tubular epithelial cells as well as marked congestion and positive, diffuse, and strong expression of caspase-3 in the dilated tubules. Additionally, the data disclosed an increase in the serum level of blood urea nitrogen (BUN) and creatinine in group III compared with group I. Group V, treated with F. indica at a selected dose of 120 mg/kg/b.wt, showed an improvement in antioxidant activity, attenuation of the IL-6 level, fewer histopathological disturbances, and a statistically significant decrease in the serum level of BUN and creatinine compared with group III. Such changes may be attributed to the antioxidant and anti-inflammatory effects of F. indica. Therefore, our investigation revealed that F. indica effectively protects against Cr-induced nephrotoxicity.

Mechanism of chromium-induced toxicity in lungs, liver, and kidney and their ameliorative agents

Heavy metal Chromium (Cr), can adversely affect humans and their health if accumulated in organs of the body, such as the lungs, liver, and kidneys. Cr (VI) is highly toxic and has a higher solubility in water than Cr (III). One of the most common routes for Cr exposure is through inhalation and is associated with liver, lung, kidney damage, widespread dermatitis, GI tract damage, human lung cancer, cardiomyopathies, and cardiovascular disease. The increase in ROS production has been attributed to most of the damage caused by Cr toxicity. Cr-induced ROS-mediated oxidative stress has been seen to cause a redox imbalance affecting the antioxidant system balance in the body. The Nrf2 pathway dysregulation has been implicated in the same. Deregulation of histone acetylation and methylation has been observed, together with gene methylation in genes such as p16, MGMT, APC, hMLH1, and also miR-143 repression. Several ultra-structural changes have been observed following Cr (VI)-toxicity, including rough ER dilation, alteration in the mitochondrial membrane and nuclear membrane, pycnotic nuclei formation, and cytoplasm vacuolization. A significant change was observed in the metabolism of lipid, glucose, and the metabolism of protein after exposure to Cr. Cr-toxicity also leads to immune system dysregulations with changes seen in the expression of IL-8, IL-4, IgM, lymphocytes, and leukocytes among others. P53, as well as pro-and anti-apoptotic proteins, are involved in apoptosis. These Cr-induced damages can be alleviated via agents that restore antioxidant balance, regulate Nrf-2 levels, or increase anti-apoptotic proteins while decreasing pro-apoptotic proteins.

Magnetite-loaded rice husk biochar promoted the denitrification performance of Aquabacterium sp. XL4 under low carbon to nitrogen ratio: Optimization and mechanism

The removal of nitrate (NO₃^--N) under the low carbon to nitrogen (C/N) ratio is a widespread issue. Here in, a modified biochar (MRHB) was prepared by combining rice husk and magnetite to promote the denitrification performance of Aquabacterium sp. XL4 under low C/N ratio. In addition, when the modified H₂O₂ concentration was 0.6 mM, the dosage was 5.0 g L^-1, the C/N ratio was 1.5, and the pH was neutral, the nitrate removal efficiency is 97.9%. Fluorescence excitation-emission matrix spectra (3D-EEM) showed that the metabolism of strain XL4 was stable under optimal conditions. Furthermore, the results of flow cytometry (FC) showed that the amounts of intact cells with MRHB was excellent. The measurement of cytochrome c concentration, total membrane permeability (T_mp), electron transport system activity (ETSA), and cyclic voltammetry curve (CV) confirmed that the MRHB improved the electron transfer and membrane activity of strain XL4.

Systemic inflammation mediates the association of heavy metal exposures with liver injury: A study in general Chinese urban adults

Heavy metal exposures have been reported to be associated with increased risk for liver injury. However, the potential mechanisms of the association remain unclear. A repeated-measure study of 9367 observations was conducted to quantify the associations of urinary heavy metals with serum alanine aminotransferase (ALT), a biomarker for liver injury, and assess the mediating role of systemic inflammation in such associations among general Chinese adults. In single-metal models, positive dose-response relationships between urinary vanadium (V), chromium (Cr), copper (Cu), arsenic (As), cadmium (Cd), tungsten (W), and lead (Pb) and serum ALT were observed. In the multiple-metal model containing the seven metals mentioned above, V and Cu remained positively associated with ALT. In longitudinal analyses of 3-6 years, each 1-unit increase in log-transformed levels of V and Cu was associated with an additional rate of annual ALT increase (95% CI) for 1.3% (0.7-1.8%) and 1.3% (0.7-2.0%), respectively. Plasma CRP concentrations were not only positively associated with urinary Cu and Cd, but also positively related with ALT. Furthermore, mediation analyses showed that CRP mediated 4.70% and 7.03% of urinary Cu- and Cd-associated ALT elevations. Our study provides clues for the prevention of heavy metal-induced liver injury.

Relative gene expression, micronuclei formation, and ultrastructure alterations induced by heavy metal contamination in Pimelia latreillei (Coleoptera: Tenebrionidae) in an urban-industrial area of Alexandria, Egypt

The present research aims to evaluate the impact of industrial processes and anthropogenic activities on the beetle Pimelia latreillei inhabiting the polluted site at Zawya Abd El- Qader, Alexandria, Egypt. Beetles were collected from the vicinity of five factories. The genotoxic effects of environmental exposures to industrial heavy metals were monitored using a broad range of assays, including energy-dispersive X ray microanalysis and X-ray diffraction (SEM and EDX)), qRT-PCR gene expression assay, micronuclei formation, and transmission electron microscope (TEM). Energy dispersive X-ray microanalysis for the soil and testicular tissues of beetles collected from the polluted site revealed a higher percentage of heavy metals than the beetles collected from the reference site (Sidi Kirier, Alexandria, Egypt). To analyze/monitor genotoxicity in P. latreillei sampled from the polluted site, the transcription levels of levels of heat shock proteins (Hsps) and accessory gland seminal fluid protein (AcPC01) in testicular tissues were recorded. The incidence of micronuclei (MN) formation in the testicular cells was also observed. Quantitative RT-PCR (RT-qPCR) analysis was carried out to detect the changes in the gene expression of the aforementioned proteins. Genes encoding heat shock proteins (Hsp60, Hsp70, and Hsp90) were significantly overexpressed (> 2-fold) in specimens sampled from the polluted site; however, AcPC01 gene expression was under-expressed (<1.5-folds). The incidence of MN was significantly increased in specimens sampled from the polluted site. Ultrastructure anomalies (nuclear and cytoplasmic disruption) were also observed in the testicular cells of the beetles sampled from the polluted site compared to those sampled from the unpolluted site. Our results, therefore, advocate a need for adequate measures to reduce increasing environmental pollution in the urban-industrial areas.

Nickel oxide nanoparticles induce genotoxicity and cellular alterations in the ground beetle Blaps polycresta (Coleoptera: Tenebrionidae)

Nickel nanoparticles (Ni-NPs) have advantageous applications in the industry; however, little is known of their adverse effects on biological tissues. In the present study, the ground beetle Blaps polycresta was employed as a sensitive indicator for nickel oxide nanoparticles (NiO-NPs) toxicity. Adult male beetles were injected with six dose levels of NiO-NPs (0.01, 0.02, 0.03, 0.04, 0.05, and 0.06 mg/g body weight). Mortality was reported daily over 30 days under laboratory conditions to establish an LD₅₀. Nickel was detected in the testicular tissues of the beetles using X-ray analysis and transmission electronic microscopy. Beetles treated with the sublethal dose of 0.02 mg/g were selected to observe molecular, cellular, and subcellular changes. Gene transcripts of HSP70, HSP90, and MT1 were found to be increased >2.5-, 1.5-, and 2-fold, respectively, in the treated group compared with the controls. Decreased gene expression of AcPC01, AcPC02, and AcPC04 (≤1.5-, ≤2-, and < 2.5-fold, respectively, vs. controls) also were reported in the treated group. Under light microscopy, various structural changes were observed in the testicular tissues of the treated beetles. Ultrastructure observations using scanning and transmission electron microscopy showed severe damage to the subcellular organelles as well as deformities of the heads and flagella of the spermatozoa. Therefore, the present study postulated the impact of NiO-NPs in an ecological model.

Acceleration mechanism of bioavailable Fe(Ⅲ) on Te(IV) bioreduction of Shewanella oneidensis MR-1: Promotion of electron generation, electron transfer and energy level

The release of highly toxic tellurite into the aquatic environment poses significant environmental risks. The acceleration mechanism and tellurium nanorods (TeNPs) characteristics with bioavailable ferric citrate (Fe(III)) were investigated in the tellurite (Te(IV)) bioreduction. Experiments showed that 5 mM Fe(III) increased the Te(IV) bioreduction rate from 0 to 12.40 mg/(L·h). Cyclic voltammetry, electrochemical impedance spectroscopy and Tafel were used to investigate electron transfer during Te(IV) bioreduction. NADH production (electron production) was significantly enhanced to 138% by Fe(III). Meanwhile Fe(III) stimulated the increase of cytochrome c, resulting in increased electron transport system activity. In addition, Fe(III) facilitated the secretion of extracellular polymeric substances (EPS) and reduced cell membrane permeability, thus reducing the toxicity of Te(IV) to cells. The increase of ATP provided energy for the metabolic process of Te(IV) bioreduction, playing an active role in cell activity. Based on the above analysis, the acceleration mechanism of Fe(III) on Te(IV) bioreduction was proposed from the aspects of electron generation, electron transfer and energy level. Zeta potential and FT-IR spectra indicated that the stability of TeNPs contributed to the covered EPS. This study provides further understanding the acceleration mechanism of Te(IV) bioreduction and promising strategy for improving the stability of TeNPs.

Detecting cadmium during ultrastructural characterization of hepatotoxicity

BACKGROUND

The threat of cadmium (Cd), which is the cause of itai-itai disease in Japan, is still complicated and confusing, especially for digestive system, such as liver disease. One of the most keys of this problem is demonstrating that the hepatotoxicity is indeed induced by Cd. Therefore, we attempt detecting Cd at microscale during ultrastructural imaging of liver tissue.

METHODS

12 rats were divided randomly into two experimental groups: control and Cd-treated. Treated rats were intraperitoneal injected with 1 mg/kg body weight cadmium chloride (CdCl₂) for 4 weeks (5 P.M each day for 6 days/week). At the end of the exposure period, liver tissue samples were processed into ultrathin sections for analysis of advanced analytical transmission electron microscopy and X-ray energy dispersive spectroscopy (TEM/X-EDS) investigations. Ultrastructural images and X-ray energy dispersive spectrum were acquired at microscale.

RESULTS

Cd can cause changes in the structure of the organelle, including the collapse of the membrane structure in the cell, the destruction of the internal structure of the organelle, the mitochondrial swelling, the expansion of the endoplasmic reticulum, and the appearance of inclusions. Cadmium bioaccumulation is detected in the mitochondria at microscale by TEM/X-EDS, which is the visual evidence of morphological changes of mitochondria related to Cd.

CONCLUSION

The combination of detailed ultrastructure and microscale X-ray energy dispersive spectroscopy (X-EDS) characterization of cadmium hepatotoxicity demonstrate that cadmium indeed leads to mitochondrial damage, which is helpful for further investigation of the pathological mechanism of cadmium hepatotoxicity.

Histological analysis of the effects of cadmium, chromium and mercury alone and in combination on the spleen of male Sprague-Dawley rats

The mining sector in South Africa is expected to be the fifth largest in the world. Both mining and transport are the most common reasons for an increased risk of human exposure to heavy metal contamination in South Africa. Due to increasing amounts of metals in the environment, this study identified three metals cadmium, chromium and mercury based on the risk of exposure in South Africa. The aim of this study was to investigate the changes in the morphology of the spleen tissue of male Sprague-Dawley rats exposed to these metals alone and in combination by using light microscopy. Forty eight animals in eight experimental groups were exposed, via oral gavage, to these metals at 1000× the World Health Organization's acceptable water limits of each respective metal, alone and in combination, for 28 days. Changes in the histological structure of the spleen were observed using haematoxylin and eosin and picrosirius red staining. Necrosis was observed in all the groups, with the severity varying between the different exposure groups, alone or in combination. Fibrosis in the spleen tissue was only seen in the experimental groups exposed to cadmium and mercury respectively, as well as in the combination of cadmium and mercury.

Cell organelles as targets of mammalian cadmium toxicity

Ever increasing environmental presence of cadmium as a consequence of industrial activities is considered a health hazard and is closely linked to deteriorating global health status. General animal and human cadmium exposure ranges from ingestion of foodstuffs sourced from heavily polluted hotspots and cigarette smoke to widespread contamination of air and water, including cadmium-containing microplastics found in household water. Cadmium is promiscuous in its effects and exerts numerous cellular perturbations based on direct interactions with macromolecules and its capacity to mimic or displace essential physiological ions, such as iron and zinc. Cell organelles use lipid membranes to form complex tightly-regulated, compartmentalized networks with specialized functions, which are fundamental to life. Interorganellar communication is crucial for orchestrating correct cell behavior, such as adaptive stress responses, and can be mediated by the release of signaling molecules, exchange of organelle contents, mechanical force generated through organelle shape changes or direct membrane contact sites. In this review, cadmium effects on organellar structure and function will be critically discussed with particular consideration to disruption of organelle physiology in vertebrates.

Induction of hepatic portal fibrosis, mitochondria damage, and extracellular vesicle formation in Sprague-Dawley rats exposed to copper, manganese, and mercury, alone and in combination

Increased anthropogenic activity and subsequent environmental exposure to heavy metals induce the production of reactive oxygen species (ROS), which increases oxidative stress and the risk of associated diseases. The aim of this study, in a subacute model of toxicity, was to investigate the effects of copper (Cu), manganese (Mn), and mercury (Hg) alone and in combination on the liver tissue of male Sprague-Dawley rats, exposed orally to 100 times the World Health Organization's acceptable water limits of each metal. General histological alterations as well as ultrastructural changes were investigated using light microscopy and transmission electron microscopy (TEM) respectively. Exposure to Cu, Mn, and Hg, alone and in combinations, caused hydropic swelling of the hepatocytes, dilation of the sinusoids, formation of binucleated hepatocytes with an increased inflammatory cell accumulation at the portal triad. Increased collagen deposition with associated fibrosis was also observed. Evaluation of hepatocyte ultrastructure revealed mitochondrial membrane damage and inner membrane swelling especially for hepatocytes exposed to Mn. Extracellular vesicle (EV) formation was observed in the liver tissue of all exposed rats. Furthermore, increased damage observed for metal combinations was possibly due to synergism. In conclusion, Cu, Mn, and Hg alone and as part of a mixture cause cellular damage, inflammation, and fibrosis increasing the risk of associated diseases.

Effects of Cadmium and /or Chromium on reproductive organs and semen profiles of male albino rats

Objective: To evaluate the potential hazards of cadmium and/or chromium on the reproductive system of adult male albino rat. Design: Randomized controlled study. Animals: Forty mature male albino rats weighing 260 ± 10 g. Procedures: Rats were allocated into four groups (ten animals each). Control group (group 1), group 2 received 4.4 mg kg-1 cadmium chloride, group 3 was given 2.5 mg kg-1 sodium dichromate and group 4 received combination of Cd (2.2 mg kg-1) and Cr (1.25mg kg-1) orally, once daily for 65 consecutive days. Results: Exposure to Cd or Cr, in particular their combination, caused a reduction in the index weights of testes, epididymis, seminal vesicle and prostate glands. They induced a reduction of sperm count and viability with an increase of abnormal sperm morphology. Interestingly, in the combination group (Cd and Cr together), the deleterious effects were more noticeable. Pathologically, both Cd and Cr produced degenerative changes in seminiferous tubules, necrosis of spermatogenic epithelium within the testis. Moreover, the interstitial tissue of epididymis showed marked edema and prostate showed necrosis and serous exudate of lining epithelium. In the interaction group, testis showed complete degenerative changes and necrosis of spermatogenic epithelium, with marked interstitial edema and hyperplastic epithelial lining of epididymal tubules. Conclusion and clinical relevance: The present results support the hypothesis that the testis is one of the most sensitive organs to Cd and/or Cr and that the exposure to any of them or to their combination lead to testicular damage and thereby male infertility.

Oral exposure to cadmium and mercury alone and in combination causes damage to the lung tissue of Sprague-Dawley rats

Environmental presence and human exposure to heavy metals in air and cigarette smoke has led to a worldwide increase in respiratory disease. The effects of oral exposure to heavy metals in liver and kidney structure and function have been widely investigated and the respiratory system as a target is often overlooked. The aim of the study was to investigate the possible structural changes in the lung tissue of Sprague-Dawley rats after oral exposure for 28 days to cadmium (Cd) and mercury (Hg), alone and in combination at 1000 times the World Health Organization's limit for each metal in drinking water. Following exposure, the general morphology of the bronchiole and lungs as well as collagen and elastin distribution was evaluated using histological techniques and transmission electron microscopy. In the lungs, structural changes to the alveoli included collapsed alveolar spaces, presence of inflammatory cells and thickening of the alveolar walls. In addition, exposure to Cd and Hg caused degeneration of the alveolar structures resulting in confluent alveoli. Changes in bronchiole morphology included an increase in smooth muscle mass with luminal epithelium degeneration, detachment and aggregation. Prominent bronchiole-associated lymphoid tissue was present in the group exposed to Cd and Hg. Ultrastructural examination confirmed the presence of fibrosis where in the Cd exposed group, collagen fibrils arrangement was dense, while in the Hg exposed group, additional prominent elastin was present. This study identified the lungs as target of heavy metals toxicity following oral exposure resulting in cellular damage, inflammation and fibrosis and increased risk of respiratory disease where Hg showed the greatest fibrotic effect, which was further, aggravated in combination with Cd.

Correlating Live Cell Viability with Membrane Permeability Disruption Induced by Trivalent Chromium

Cr(III) is often regarded as a trace essential micronutrient that can be found in many dietary supplements due to its participation in blood glucose regulation. However, increased levels of exposure have been linked to adverse health effects in living organisms. Herein, scanning electrochemical microscopy (SECM) was used to detect variation in membrane permeability of single cells (T24) resulting from exposure to a trivalent Cr-salt, CrCl₃. By employing electrochemical mediators, ferrocenemethanol (FcMeOH) and ferrocenecarboxylic acid (FcCOO^-), initially semipermeable and impermeable, respectively, complementary information was obtained. Three-dimensional COMSOL finite element analysis simulations were successfully used to quantify the permeability coefficients of each mediator by matching experimental and simulated results. Depending on the concentration of Cr(III) administered, three regions of membrane response were detected. Following exposure to low concentrations (up to 500 μM Cr(III)), their permeability coefficients were comparable to that of control cells, 80 μm/s for FcMeOH and 0 μm/s for FcCOO^-. This was confirmed for both mediators. As the incubation concentrations were increased, the ability of FcMeOH to permeate the membrane decreased to a minimum of 17 μm/s at 7500 μM Cr(III), while FcCOO^- remained impermeable. At the highest examined concentrations, both mediators were found to demonstrate increased membrane permeability. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell viability studies were also conducted on Cr(III)-treated T24 cells to correlate the SECM findings with the toxicity effects of the metal. The viability experiments revealed a similar concentration-dependent trend to the SECM cell membrane permeability study.

The antagonistic effect of selenium on cadmium-induced apoptosis via PPAR-γ/PI3K/Akt pathway in chicken pancreas

The animal experiment was preformed to investigate the roles of PPAR-γ/PI3K/Akt pathway in apoptosis triggered by cadmium (Cd) and in the antagonistic effects of selenium (Se) on Cd in the pancreas of chicken. The current study showed that Cd treatment obviously increased the accumulation of Cd and directly led to lower activities of amylase, trypsin and lipase in chicken pancreas. The expression of PPAR-γ, PI3K, and Akt was declined, whereas the level of Bax, Cyt C and caspase-3 were increased in Cd group. In the result of TUNEL assay and the histological examination, typical apoptosis characteristics in the pancreas of Cd group were confirmed. Cd group also showed high levels of inducible nitric oxide synthase (iNOS) activity and nitric oxide (NO) content in pancreas. However, those Cd-induced changes were obviously alleviated in Cd + Se group. Our study revealed that Cd could impact the pancreas function and induce the activation of Bax and the overproduction of NO via PPAR-γ/PI3K/Akt pathway to promote apoptosis in chicken pancreas. However, Se could reduce Cd accumulation and antagonize Cd-triggered apoptosis in chicken pancreas.

Flavocoxid, a Natural Antioxidant, Protects Mouse Kidney from Cadmium-Induced Toxicity

Background

Cadmium (Cd), a diffused environmental pollutant, has adverse effects on urinary apparatus. The role of flavocoxid, a natural flavonoid with antioxidant activity, on the morphological and biochemical changes induced in vivo by Cd in mice kidney was evaluated.

Methods

C57 BL/6J mice received 0.9% NaCl alone, flavocoxid (20 mg/kg/day i.p.) alone, Cd chloride (CdCl₂) (2 mg/kg/day i.p.) alone, or CdCl₂ plus flavocoxid (2 mg/kg/day i.p. plus 20 mg/kg/day i.p.) for 14 days. The kidneys were processed for biochemical, structural, ultrastructural, and morphometric evaluation.

Results

Cd treatment alone significantly increased urea nitrogen and creatinine, iNOS, MMP-9, and pERK 1/2 expression and protein carbonyl; reduced GSH, GR, and GPx; and induced structural and ultrastructural changes in the glomeruli and in the tubular epithelium. After 14 days of treatment, flavocoxid administration reduced urea nitrogen and creatinine, iNOS, MMP-9, and pERK 1/2 expression and protein carbonyl; increased GSH, GR, and GPx; and showed an evident preservation of the glomerular and tubular structure and ultrastructure.

Conclusions

A protective role of flavocoxid against Cd-induced oxidative damages in mouse kidney was demonstrated for the first time. Flavocoxid may have a promising antioxidant role against environmental Cd harmful effects on glomerular and tubular lesions.