Prenatal double-hit with aluminium and cadmium mediate testicular atrophy and hypothalamic hypoplasia: the role of oxido-nitrergic stress and endocrine perturbations

There is limited experimental evidence on the biochemical consequences of aluminium (Al) and cadmium (Cd) co-exposures during pregnancy and postnatal life.This study investigated the impacts of perinatal Al chloride (AlCl3) and Cd chloride (CdCl2) co-exposures on neuroendocrine functions in mice offspring during postnatal life. The study comprised of four pregnant experimental groups. Group 1 received AlCl3 (10 mg/kg), group 2 were administered CdCl2 (1.5 mg/kg), while group 3 received both AlCl3 (10 mg/kg) and CdCl2 (1.5 mg/kg) (AlCl3+CdCl2), and group 4 received saline (10 mL/kg) only and served as control group. All experimental animals were chemically exposed once daily from gestation days 7-20. Upon delivery, male pups were regrouped based on maternal chemical exposure on postnatal day 21 (PND 21) and allowed to grow to adulthood until PND 78, after which they were sacrificed for assessment of neuroendocrine markers and histological investigations. There was no statistical significance (p > 0.05) on follicle stimulating hormone, testosterone, estrogen and progesterone, thyroid stimulating hormone, thyroxine (T4) in all treatment groups relative to controls|. However, AlCl3 and AlCl3-CdCl2 significantly (p < 0.05) reduced triiodothyronine (T3) levels, with a profound increase in T3:T4 ratio by AlCl3, and AlCl3+CdCl2 compared to control. Furthermore, pups from pregnant mice treated with CdCl2 and AlCl3+CdCl2 demonstrated increased testicular malondialdehyde concentration with increased catalase activity relative to controls, suggesting oxidative imbalance. In addition, AlCl3, CdCl2, and AlCl3+CdCl2 exposures induced testicular and hypothalamic architectural disruption compared to controls, with marked architectural derangement in the AlCl3+CdCl2 group. Our findings suggest that prenatal co-exposures to Alcl3 and CdCl2 induce testicular and hypothalamic alterations in offspring via a testicular oxidative stress and thyrotoxicosis-dependent mechanisms.

Multi-endpoint analysis of cadmium chloride-induced genotoxicity shows role for reactive oxygen species and p53 activation in DNA damage induction, cell cycle irregularities, and cell size aberrations

Cadmium chloride (CdCl2) is a known genotoxic carcinogen, with a mechanism of action thought to partly involve the generation of reactive oxygen species (ROS). We applied here a multi-endpoint approach in vitro to explore the impact of CdCl2 on both the genome and on wider cell biology pathways relevant to cancer. Multi-endpoint approaches are believed to offer greater promise in terms of understanding the holistic effects of carcinogens in vitro. This richer understanding may help better classification of carcinogens as well as allowing detailed mechanisms of action to be identified. We found that CdCl2 caused DNA damage [micronuclei (MN)] in both TK6 and NH32 cells in a dose-dependent manner after 4 h exposure (plus 23 h recovery), with lowest observable effect levels (LOELs) for MN induction of 1 μM (TK6) and 1.6 μM (NH32). This DNA damage induction in TK6 cells was ROS dependent as pretreatment with the antioxidant N-Acetyl Cysteine (1 mM), abrogated this effect. However, 2',7'-dichlorofluorescin diacetate was not capable of detecting the ROS induced by CdCl2. The use of NH32 cells allowed an investigation of the role of p53 as they are a p53 null cell line derived from TK6. NH32 showed a 10-fold increase in MN in untreated cells and a similar dose-dependent effect after CdCl2 treatment. In TK6 cells, CdCl2 also caused activation of p53 (accumulation of total and phosphorylated p53), imposition of cell cycle checkpoints (G2/M) and intriguingly the production of smaller and more eccentric (elongated) cells. Overall, this multi-endpoint study suggests a carcinogenic mechanism of CdCl2 involving ROS generation, oxidative DNA damage and p53 activation, leading to cell cycle abnormalities and impacts of cell size and shape. This study shows how the integration of multiple cell biology endpoints studied in parallel in vitro can help mechanistic understanding of how carcinogens disrupt normal cell biology.

Effect of lactoferrin supplement on cadmium chloride induced toxicity to male rats: Toxicopathological, ultrastructural and immunological studies

This study sought to determine whether lactoferrin supplementation could counteract the harm that cadmium (Cd) induced to the rats. The effect of Cd and lactoferrin were investigated in hematological, biochemical, histological, immunohistochemical expression and ultrastructural studies. After 30 days of treatment, rats exposed to Cd had significantly higher levels of Cd in their blood, more oxidized lipids, and less antioxidant capacity overall. Supplemental lactoferrin also significantly undoes that effect. Hematological and biochemical parameters changed along with the increase in blood Cd levels. The histological integrity of the liver, kidney, spleen, and (axillary, cervical, mesenteric and popliteal) lymph nodes that had been damaged by Cd exposure was also restored by lactoferrin supplementation. Moreover, the liver and spleen ultrastructure showed the same improvement. In addition, the spleen of Lf/Cd group showed less immunohistochemical expression of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) in comparison to the Cd group. In conclusion, the current study showed that supplementing with lactoferrin improved immune response and restored biochemical and oxidative stability induced by Cd.

Effects of cadmium on liver function in turtle Mauremys reevesii

This research was designed to investigate the effects of cadmium (Cd) on liver function in turtle Mauremys reevesii. Turtles were divided into 4 groups at random. The turtles were injected intraperitoneally with Cd at 0, 7.5, 15, 30 mg kg-1 Cd chloride separately. Liver index was calculated. The activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and the content of TP in liver were examined with biochemical methods. The results indicated that the liver index of turtles changed obviously only at higher dose and longer time. The activities of ALT and AST in liver increased with prolongation of exposure time in a dose-dependent manner. TP content in liver was lower than that in the control. In summary, Cd had an obvious toxic effect on liver tissues of freshwater turtle Mauremys reevesii, and it was dose dependent with the extension of exposure time. But the results also showed that the turtle had strong tolerance to Cd.

Immunostimulatory and anti-inflammatory impact of Fragaria ananassa methanol extract in a rat model of cadmium chloride-induced pulmonary toxicity

Cadmium is an extremely dangerous heavy metal that can lead to disastrous consequences in all organisms. Several natural remedies reduce the toxicities of experimentally generated metals in animals. Strawberry Fragaria ananassa contains several bioactive compounds that may mitigate heavy-metal toxicity. The study aim was to evaluate the ability of a strawberry fruit methanol extract (SE) to reduce Cd toxicity and to identify and quantify the active constituents of SE. Forty Wistar rats were classified into four groups: the control group- 1 ml saline IP; SE group- 100 mg of SE/kg rats orally; cadmium (Cd) group-2 mg CdCl2/kg body weight/IP daily; and treated group- SE given 1 hour before Cd administration. Administration of Cd induced several histopathological and immunohistochemical alterations in lung sections. Biochemical analysis of lung homogenates and mRNA levels of antioxidants and inflammatory cytokines indicated significant changes to the risk profile. SE administration significantly decreased the oxidative stress, inflammation, tissue damage, the mean area percentage of collagen fibers, and positive immuno-expressions of TNF-α and NF-κB induced by CdCl2. Moreover, the MDA, TNF-α, GM-CSF, and IL-1β levels in Cd-exposed rat lung tissue were significantly lower in the SE-treated group than in the Cd-group. SE significantly augmented lung GSH, SOD, HO-1, GPx-2, and Nrf2 levels in Cd-exposed rats. SE mitigated Cd-caused oxidative stress and lung inflammation. Therefore, regularly consuming a strawberry-rich diet could benefit general health and help prevent and treat diseases.

Naphthaleneoxypropargyl-Containing Piperazine as a Regulator of Effector Immune Cell Populations upon an Aseptic Inflammation

This study investigated the effects of aseptic inflammation and heavy metal exposure on immune responses, as well as the potential immunomodulatory properties of the newly synthesized 1-[1-(2,5-dimethoxyphenyl)-4-(naphthalene-1-yloxy)but-2-ynyl]-4-methylpiperazine complexed with β-cyclodextrin (β-CD). Aseptic inflammation was induced by a subcutaneous injection of turpentine in rats, while heavy metal exposure was achieved through a daily administration of cadmium chloride and lead acetate. The levels of immune cell populations, including cytotoxic T lymphocytes (CTL), monocytes, and granulocytes, were assessed in the spleen. The results showed that aseptic inflammation led to decreased levels of CTL, monocytes, and granulocytes on the 14th day, indicating an inflammatory response accompanied by a migration of effector cells to the inflamed tissues. The exposure to cadmium chloride and lead acetate resulted in systemic immunotoxic effects, with reduced levels of B cells, CD4+ Th cells, monocytes, and granulocytes in the spleen. Notably, piperazine complexed with β-CD (the complex) exhibited significant stimulatory effects on CD4+, CD8+, and myeloid cell populations during aseptic inflammation, even in the presence of heavy metal exposure. These findings suggest the potential immunomodulatory properties of the complex in the context of aseptic inflammation and heavy metal exposure.

Vanillin attenuates CdCl2-induced cytotoxicity in isolated human erythrocytes

Cadmium is a toxic heavy metal with no physiological role in the human body. Cadmium has high mobility due to its widespread industrial use, with no safe and effective therapeutic management. Cadmium toxicity manifests by increasing oxidative stress in target cells. We have explored the potential role of vanillin, a plant phenolic aldehyde and antioxidant, in mitigating cadmium chloride (CdCl2) induced hemotoxicity using isolated human erythrocytes. CdCl2 was added to erythrocytes, in the absence and presence of vanillin. Incubation of erythrocytes with CdCl2 alone inhibited methemoglobin reductase and enhanced methemoglobin level. Heme degradation and release of free iron (Fe2+), along with protein and membrane lipid oxidation, were also increased. A CdCl2-induced enhancement in reactive oxygen and nitrogen species was also seen, lowering the overall antioxidant power of cells. However, pre-incubation of erythrocytes with vanillin resulted in significant decreased generation of reactive species and prevented heme degradation and heme oxidation. Vanillin augmented the erythrocyte antioxidant capacity and reinstated the activities of major antioxidant, plasma membrane-bound and glucose metabolism enzymes. Scanning electron microscopy showed that CdCl2 treatment led to the formation of echinocytes which was prevented by vanillin. In all cases, no harmful effects of vanillin alone were seen. Thus, vanillin alleviates the toxicity of cadmium and can be potentially employed as a chemoprotectant against the damaging effects of this heavy metal.

The imprinted gene Zac1 regulates steatosis in developmental cadmium-induced nonalcoholic fatty liver disease

Cadmium (Cd) exposure in adulthood is associated with nonalcoholic fatty liver disease (NAFLD), characterized by steatosis, inflammation, and fibrosis. The prevalence of NAFLD in children is increasing, suggesting a role for the developmental environment in programming susceptibility. However, the role of developmental Cd exposure in programming NAFLD and the underlying mechanisms remain unclear. We have proposed that imprinted genes are strong candidates for connecting the early life environment and later life disease. In support of this, we previously identified roles for the Imprinted Gene Network (IGN) and its regulator Zac1 in programming NAFLD in response to maternal metabolic dysfunction. Here, we test the hypothesis that developmental Cd exposure is sufficient to program NAFLD, and further, that this process is mediated by Zac1 and the IGN. Using mice, we show that developmental cadmium chloride (CdCl2) exposure leads to histological, biochemical, and molecular signatures of steatosis and fibrosis in juveniles. Transcriptomic analyses comparing livers of CdCl2-exposed and control mice show upregulation of Zac1 and the IGN coincident with disease presentation. Increased hepatic Zac1 expression is independent of promoter methylation and imprinting statuses. Finally, we show that over-expression of Zac1 in cultured hepatocytes is sufficient to induce lipid accumulation in a Pparγ-dependent manner and demonstrate direct binding of Zac1 to the Pparγ promoter. Our findings demonstrate that developmental Cd exposure is sufficient to program NAFLD in later life, and with our previous work, establish Zac1 and the IGN as key regulators of prosteatotic and profibrotic pathways, two of the major pathological hallmarks of NAFLD.

An assessment of the ameliorative role of hesperidin in Drosophila melanogaster model of cadmium chloride-induced toxicity

Cadmium chloride (CdCl₂) is an important heavy metal widely regarded as an environmental contaminant. Hesperidin, a flavanone glycoside found in citrus fruits, has an established properties against free radicals, apoptosis, and inflammation. The present study investigated the protective actions of hesperidin on CdCl₂-induced oxidative damage and inflammation in Drosophila melanogaster. For 7 consecutive days via their diet regimen, the flies were exposed to CdCl₂ alone (0.05 mM) or in combination with hesperidin (50 and 100 μM). Exposure to CdCl₂ significantly (p < 0.05) increased mortality rate of flies, whereas the survived flies demonstrated significant oxidative toxicity from decreased activities of catalase and Glutathione S-transferase (GST) and Total Thiol (T-SH) and Non-Protein Thiols (NPSH) levels as well as accumulation of Nitric Oxide (NO (nitrite/nitrate)), protein carbonyl and Hydrogen Peroxide (H₂O₂). However, hesperidin-supplemented diet improved Acetylcholinesterase (AChE) activity, mitochondrial metabolic rate (cell viability), locomotor activity, and amelioration of oxidative damage and lipid peroxidation induced by CdCl₂. The hesperidin diet supplement boosted the antioxidant milieu and ameliorated the oxidative damage in the treated flies. Overall, the findings revealed that hesperidin improved antioxidative protective capacity in Drosophila melanogaster model of CdCl₂-induced toxicity. This suggests hesperidin as a potential therapeutic agent against oxidative stress disorders due to exposure to CdCl₂ and or related toxicants.

[Role of autophagy in cadmium-induced damage to the blood-testis barrier in mice]

OBJECTIVE

To investigate the role of autophagy in cadmium chloride (CdCl2)-induced damage to the blood-testis barrier (BTB) in mice.

METHODS

Twenty four-week-old male C57BL/6 mice were randomly divided into four groups and intraperitoneally injected with CdCl2 at 0 mg/kg/d (the control), 0.5 mg/kg/d (low-dose), 1.0 mg/kg/d (medium-dose) and 2.0 mg/kg/d (high-dose) respectively for 28 consecutive days. Then the morphological changes of the testis tissue was observed by HE staining, the integrity of BTB measured with the biotracer, and the expressions of the BTB components ZO-1 and N-Cadherin proteins detected by Western blot. The TM4 Sertoli cells were treated with CdCl2at 0, 2.5, 5 and 10 μmol/L respectively for 24 hours, followed by determination of the expression levels of ZO-1 and N-Cadherin as well as the autophagy-related proteins LC3II and p62. Then the cells were again treated with CdCl2 in the presence of the autophagy inhibitor chloroquine (CQ) at 5 μmol/L or the autophagy inducer rapamycin (Rap) at 50 nmol/L for 24 hours, followed by measurement of the expressions of LC3II, p62, ZO-1 and N-Cadherin by Western blot.

RESULTS

Compared with the control group, the cadmium-exposed mice showed increased interstitial space in the seminiferous tubules, formation of intracellular cavitation in the germ cells with decreased layers and disordered arrangement, and damaged integrity of the BTB. The expressions of the ZO-1 and N-Cadherin proteins were significantly down-regulated in the testis tissue of the mice in the medium- and high-dose CdCl2 groups (P < 0.05), and even more significantly in the CdCl2-exposed cells in comparison with those in the control mice (P < 0.01), while the expressions of the LC3II and p62 proteins were remarkably up-regulated (P < 0.05). The expressions of ZO-1, N-Cadherin, LC3II and p62 were also up-regulated in the cells co-treated with CQ and CdCl2 (P < 0.01), those of ZO-1, N-Cadherin and p62 down-regulated (P< 0.05) and that of LC3II up-regulated (P < 0.05) in the cells co-treated with Rap and CdCl2.

CONCLUSION

CdCl2 can damage the integrity of the mouse BTB, which may be attributed to its ability to enhance the autophagy in Sertoli cells and regulate the expressions of BTB proteins.

Effects of a novel probiotic mixture on the modulation of brain and intestine Aquaporin-4 gene expression in rats exposed to Cadmium

Cadmium (Cd) is a toxicant metal that risks human and animal health. Nowadays, the vital role of Aquaporin-4 (AQP-4) in brain and gut cell permeability has gathered too much attention to protecting against heavy metals. Studies have shown that heavy metals can harm the body due to oxidative stress. Probiotics are known for their health-beneficial effects and establish as dietary adjuncts mainly for their antioxidant properties. This study investigated the impact of a novel probiotic combination including Lactobacillus casei IBRC-M10783, Lactobacillus rhamnosus IBRC-M10782, and Lactobacillus helveticus TG-34 on the AQP-4 gene expression in CdCl2-induced Wistar rats. Rats were divided into three groups and received a specific dose of CdCl2 or probiotics. The AQP-4 expression level had estimated by Real-Time PCR in both the intestine and brain. These results showed a significant reduction in AQP-4 gene expression in the probiotic treatment group compared to the CdCl2 control group in the intestine and brain for the first time. Our research showed that consuming a probiotic mixture of L. casei, L. rhamnosus, and L. helveticus can reduce the expression of the aquaporin-4 gene in the brain and intestine of rats exposed to Cadmium, which can be promising in the field of aquaporin-4 regulation.

[Renal injury induced by cadmium chloride and the protective effect of vitamin C in mice]

OBJECTIVE

To investigate the renal injury induced by cadmium chloride(CdCl_2) and the protective effect of vitamin C(VC) in mice.

METHODS

Forty healthy clean grade male Kunming mice were randomly divided into 4 groups: control group(double distilled water gavage and intraperitoneal injection), VC group(200 mg/kg VC gavage and double distilled water intraperitoneal injection), CdCl_2 group(double distilled water gavage and 2 mg/kg CdCl_2 intraperitoneal injection), VC+CdCl_(2 )group(200 mg/kg VC gavage and 2 mg/kg CdCl_2 intraperitoneal injection). Exposure for 30 days.24 hours after the last exposure, the eyeballs were taken out for blood, and the renal tissue was immediately taken out to calculate kidney coefficient and then separate renal cells. The levels of reactive oxygen species(ROS) were detected by DCFH-DA kit and flow cytometry. Blood urea nitrogen(BUN), serum creatinine(Scr)and β2 microglobulin(β2-MG), cystatin C(Cys C), superoxide dismutase(SOD), glutathione peroxidase(GSH-Px), malondialdehyde(MDA), Caspase3 and Caspase9 kits were used to detect the corresponding indicators respectively. The contents of Cd~(2+) and Zn~(2+) in serum and kidney were detected by graphite furnace atomic absorption spectrometry.

RESULTS

The levels of kidney coefficient and BUN, Scr, β2-MG were 1.36±0.10, (19.34±0.63)mmol/L, (61.30±2.04)mmol/L and(1.02±0.10)g/mL respectively in CdCl_(2 )group, which were higher than those in the control group and VC group(P&lt;0.05). The levels of the above four indexes in VC+CdCl_(2 )group were 1.09±0.10, (9.65±0.50)mmol/L, (41.85±1.27)mmol/L and(0.61±0.01)g/mL respectively, which were lower than those in CdCl_2 group(P&lt;0.05). CdCl_2 exposure resulted in unclear glomerular contour, swelling of renal tubules, interstitial hyperemia, and exfoliated epithelial cells in the lumen. VC pretreatment could improve the above changes. The levels of Cd~(2+) in serum and renal tissue of mice in CdCl_2 group were(4.36±0.07)μg/L, (18.6±1.95)μg/g respectively, which were higher than that of control group and VC group(P&lt;0.05), in VC+CdCl_2 group, the level were(2.12±0.06)μg/L and(2.18±0.09)μg/g, they were lower than that of CdCl_2 group(P&lt;0.05). The level of serum Zn~(2+ )in CdCl_2 group was(11.35±1.03)μg/L, that was lower than control group(P&lt;0.05). The level of serum Zn~(2+) in VC+CdCl_2 group was(26.98±3.13)μg/L, which was higher than that of CdCl_2 group(P&lt;0.05). The levels of ROS, MDA, Caspase3 and Caspase9 in kidney tissue of mice in CdCl_2 group were(1.86±0.13), (4.78±0.15)nmol/mg, 1.50±0.24 and 1.69±0.17 respectively, which were higher than those in control group(P&lt;0.05). And the level of GSH-Px was(261.3±23.36)U/mg, it was lower than that in control group(P&lt;0.05). Compared with the CdCl_2 group, the levels of ROS, MDA, Caspase3 and Caspase9 in VC+CdCl_2 group decreased, and the level of GSH-Px increased, the difference was statistically significant(P&lt;0.05).

CONCLUSION

CdCl_2 exposure can lead to oxidative stress, damage of glomerulus and renal tubules, imbalance of zinc ion homeostasis, and damage of renal function. VC pretreatment can reduce the damage caused by CdCl_2 to a certain extent.

Alleviation of Cadmium Chloride-Induced Acute Genotoxicity, Mitochondrial DNA Disruption, and ROS Generation by Chocolate Coadministration in Mice Liver and Kidney Tissues

Increased human exposure to cadmium compounds through ingesting contaminated food, water, and medications causes negative long-term health effects, which has led to the focus of recent researches on finding natural antioxidants to mitigate cadmium-induced toxicity. Therefore, the current study was undertaken to estimate the possible ameliorative effect of chocolate coadministration on acute cadmium chloride (CdCl₂)-induced genomic instability and mitochondrial DNA damage in mice liver and kidney tissues. Concurrent administration of chocolate with CdCl₂ dramatically decreased the DNA damage level and the number of apoptotic and necrotic cells compared to mice given CdCl₂ alone. Extra-production of reactive oxygen species and increased expression of inducible nitric oxide synthase and heat shock proteins genes caused by CdCl₂ administration were also highly decreased after chocolate coadministration. Conversely, chocolate coadministration restored the integrity of the mitochondrial membrane potential disrupted by CdCl₂ administration, as well as the mitochondrial DNA copy number and expression level of heme oxygenase-1 gene were significantly upregulated after chocolate coadministration with CdCl₂. Thus, it was concluded that the coadministration of chocolate alleviated CdCl₂-induced genomic instability and mitochondrial DNA damage through its antioxidative and free radical scavenging capabilities, making chocolate a promising ameliorative product and recommended for inclusion in the daily human diet.

In Vivo Attenuation of Alcohol- and Cadmium Chloride-Induced Testicular Toxicity Modulated by Silymarin in Male Wistar Rat

The aim of the study is to investigate the in vivo attenuation of alcohol- and cadmium chloride-induced testicular toxicity modulated by Silymarin in male Wistar rats. A total of fifty-six (56) Wistar rats were used for this study and they were randomized into seven (7) groups of eight (8) rats each. Group 1 was control rats; Groups 2-7 served as the experimental groups. After 6 weeks treatment duration, the rats were euthanized, semen was collected for semen analysis, blood samples for testosterone, and FSH and LH assay determination, and left testes was harvested for histological analysis. One-way ANOVA was used to compare means at p-level < 0.05 was considered significant. Findings from this study have shown that alcohol and cadmium chloride adversely affected semen parameters, testosterone, and FSH and LH hormone milieu. Data also showed that Silymarin administration attenuated the adverse effect of alcohol and cadmium chloride on semen quality and hormones associated with reproductive functions. Hence, Silymarin mopped the effect of in vivo attenuation of alcohol and cadmium chloride testicular damage. The findings of this study have further established that alcohol and cadmium chloride adversely affected semen parameters, testicular alterations, and serum hormonal milieu. However, the effect was more significantly deleterious in rats exposed to cadmium chloride when compared to rats exposed to alcohol, subsequently alcohol- and cadmium chloride-induced degeneration of testicular tissues. Furthermore, Silymarin administration attenuated the adverse effect of alcohol on semen quality and hormones associated with reproductive functions.

Deep learning approach identified a gene signature predictive of the severity of renal damage caused by chronic cadmium accumulation

Epidemiology studies have indicated that environmental cadmium exposure, even at low levels, will result in chronic cadmium accumulation in the kidney with profound adverse consequences and that the diabetic population is more susceptible. However, the underlying mechanisms are yet not fully understood. In the present study, we applied an animal model to study chronic cadmium exposure-induced renal injury and performed whole transcriptome profiling studies. Repetitive CdCl₂ exposure resulted in cadmium accumulation and remarkable renal injuries in the animals. The diabetic ob/ob mice manifested increased severity of renal injury compared with the wild type C57BL/6 J littermate controls. RNA-Seq data showed that cadmium treatment induced dramatic gene expression changes in a dose-dependent manner. Among the differentially expressed genes include the apoptosis hallmark genes which significantly demarcated the treatment effects. Pathway enrichment and network analyses revealed biological oxidation (mainly glucuronidation) as one of the major stress responses induced by cadmium treatment. We next implemented a deep learning algorithm in conjunction with cloud computing and discovered a gene signature that can predict the degree of renal injury induced by cadmium treatment. The present study provided, for the first time, a comprehensive mechanistic understanding of chronic cadmium-induced nephrotoxicity in normal and diabetic populations at the whole genome level.

Histopathological evaluation of IBA-1, GFAP activity in the brain cortex of rats administered cadmium chloride

Purpose: This study aims to evaluate the changes in brain tissue and blood-brain barrier due to oxidative stress during cadmium (Cd) poisoning by biochemical, histopathological, and immunohistochemical methods. Methods: 170-190 g weighing eight-week-old female Wistar albino rats were divided into two groups (control and experimental), with 7 animals in each group. Experimental group rats were given 2 mg/kg/day powdered cadmium chloride dissolved in water intraperitoneally every day for two weeks. Biochemical, histopathological and immunohistochemical examination was performed. Results: It was seen that brain malondialdehyde (MDA) levels increased significantly, and glutathione (GSH) and catalase (CAT) activity levels decreased. In addition to degeneration in some pyramidal cells and glial cells, deformity, and picnosis in the nucleus, dilation of the meninges and cortex vessels, and inflammation around the blood vessels were observed. An increase was found in ionized calcium binding adaptor molecule 1 (IBA-1) expression in microglia cells and degenerative endothelial cells, and increased glial fibrillary acidic protein (GFAP) expression was observed in astrocytes and degenerate neurons. Conclusions: It has been shown that cadmium toxicity may cause microgliosis and astrogliogenesis by inducing cytokine production due to cell degeneration, vascularity, and inflammation in the brain cortex and by affecting microglia, astrocytes cells.

Potential protective effect of beta-caryophyllene against cadmium chloride-induced damage to the male reproductive system in mouse

Cadmium is a metal that can affect the male reproductive process, possibly leading to infertility. In contrast, beta-caryophyllene (BC) is a sesquiterpene that has shown antigenotoxic, anticancer, and antioxidant properties. Therefore, the aim of the present study was to determine the protective effect of BC against the deleterious effects of cadmium chloride (CC) on various mouse testicular and sperm parameters. We tested three doses of BC (20, 200, and 400 mg/kg) given before and during exposure to 3 mg/kg CC (six days after a single administration). Our results show significant alleviation of the damage induced by CC after the three doses of BC. Regarding the sperm concentration and morphology, the protection with the high dose was complete, and regarding sperm mobility and viability, the protection was more than 74%. In the comet assay, the highest dose showed a reduction of 92.5% in the damage induced by CC, and regarding the number of micronuclei in the spermatids, the reduction was 83.3%. In the oxidative evaluation, regarding sperm lipoperoxidation, the improvement was complete with the high dose, and in the ABTS^.+ test, the improvement in the response to the BC high dose was 26.3%. Regarding testicular lipoperoxidation and protein oxidation, the protective effects of the high BC dose were 87.6% and 89.9%, respectively. We also found that BC protected against the histological and morphometric alterations induced by CC. Therefore, our study clearly demonstrates the beneficial, chemopreventive effect of BC against the mouse sperm and testicular alterations induced by CC.

Acute Toxicity Bioassay and Determination of LC50 of Cadmium Chloride in Trichogaster (Colisa) fasciata

Cadmium chloride is a metal salt used in industries in a large scale. Trichogaster (Colisa) fasciata (common name banded gourami) is an air-breathing fresh water fish with both nutritional and ornamental values. In this present study, as per EPA guidelines, acute toxicity bioassay was performed in a 96-h static test method in four replicates, each replicate having one control and five concentrations (25, 50, 75, 100 and 125 mg/L, respectively) of the metal salt. A total of 192 fish was used in the study in four series with each replicate containing 8 fish per concentration. The water temperature was maintained at 20-22℃ during the study. The data observed were analysed statistically on the basis of Finney's Probit Analysis method using SPSS software. The estimated 96-h LC₅₀ value of cadmium chloride for the fish was 49.5 mg/L.

Cadmium chloride-induced apoptosis of HK-2 cells via interfering with mitochondrial respiratory chain

Cadmium could induce cell apoptosis, probably related to the dysfunction of the mitochondrial respiratory chain. The human renal proximal tubule (HK-2) was used to explore the mechanism of mitochondrial respiratory chain dysfunction during apoptosis induced by cadmium chloride (CdCl₂). Cell viability was evaluated by cell proliferation assay and different concentrations of 60, 80 and 100 μM were selected to evaluate the mitochondrial toxicity of CdCl₂ respectively. Under the CdCl₂ treatment for 24 h, the mitochondrial reactive oxygen species (ROS) of HK-2 cells increased and the superoxide dismutase (SOD) activity was inhibited at the above three concentrations separately. Both ATP content and mitochondrial membrane potential decreased significantly at 100 μM concentration. The levels of procaspase-3 and Bcl-2 had fallen in a concentration-dependent manner and Bax was significantly increased at 60, 80 and 100 μM concentration compared with no CdCl₂ treatment respectively, which activated the mitochondrial apoptosis pathway. N-acetyl-cysteine (NAC) could partially resist CdCl₂-induced cell apoptosis, while myxothiazol (Myx) promoted the process. Mitochondria relative alterations manifested as inhibition of complex III and V. In addition, both the quantity of mitochondrial coenzyme Q-binding protein CoQ10 homolog B (CoQ10B) and cytochrome c (Cyt c) had decreased significantly. Taken together, CdCl₂ induced HK-2 apoptosis due to the mitochondrial respiratory chain dysfunction by reducing the CoQ10B level, offering a novel evaluating indicator for the environmental toxicity of CdCl₂.

Ameliorative effects of a curcumin vitamin E nanocomposite coated with olive oil against cadmium chloride-induced testicular damage

In the current study, we synthesized and prepared a curcumin and vitamin E nanocomposite coated with olive oil (CEONC). Curcumin, vitamin E, and olive oil are fundamental organic antioxidants, and forming nanoparticles from these components endows them with special characteristics. We investigated the protective effect of CEONC on reproductive toxicity induced by cadmium chloride (CdCl2 ) in male rats. Forty rats (170-180 g) were randomly assigned to four groups: Group 1 (control) received oral distilled water; Group 2 intraperitoneal injection with CEONC (30 mg/kg); Group 3 received oral CdCl2 (5 mg/kg); and Group 4 received CdCl2 (5 mg/kg) followed by CEONC (30 mg/kg) for 4 weeks. After 50 days, we terminated the experiment and assessed male reproductive hormones, sperm motility, viability and morphology, and testes histopathology and conducted a comet assay. The results revealed that co-administration of CEONC with CdCl2 exposure increased reproductive hormone levels, improved sperm motility and viability, prevented sperm morphological changes, recovered the testicular histology, and decreased DNA damage in the testicular tissue compared to rats exposed to CdCl2 alone. CEONC administration produced no adverse effects and enhanced all sperm parameters. Our findings demonstrate that CEONC is a potential treatment for preventing reproductive damage induced by cadmium exposure.

Rutin Improves Cardiac and Erythrocyte Membrane-Bound ATPase Activities in Male Rats Exposed to Cadmium Chloride and Lead Acetate

Cardiovascular diseases have been associated with cadmium (Cd) and lead (Pb). Impaired Ca²⁺ and Na⁺/K⁺-ATPase activities have also been linked to hemolytic and cardiovascular disorders. This study investigated the effect of rutin on Cd and/or Pb-induced cardiac and erythrocyte disorders in male rats. Twenty-five (25) male Wistar rats were treated as (n=5): Control, Pb (60 mg/kg, p.o), Cd (5 mg/kg, p.o), Pb + Cd, Rutin + Pb + Cd (50 mg/kg Rt, 60 mg/kg Pb, 5 mg/kg Cd, p.o). Plasma electrolyte and Ca²⁺- and Na⁺/K⁺-ATPase activities in the erythrocyte and heart of the rats were assayed. There was an increased and decreased activity of cardiac and erythrocyte Na⁺/K⁺-ATPase in Pb- (172%) and Cd- (33.7%) treated groups, respectively. However, rutin increased erythrocyte Na⁺/K⁺-ATPase activity in Cd + Pb when compared with Cd and Cd + Pb groups. Erythrocyte Ca²⁺-ATPase activity was decreased in the Pb (68%), Cd (68%) and Cd + Pb (55.3%) groups. Cardiac Na⁺/K⁺-ATPase activity was not altered in Pb and Cd groups while it decreased in Cd + Pb. Rutin increased the activity of the pump in Cd +Pb-treated rats compared to the Cd+Pb group. Therefore, rutin reversed cadmium- and lead-induced impaired cardiac and erythrocyte membrane Ca²⁺- and Na⁺/K⁺-ATPase activities. Graphical Abstract Dotted lines-decrease activity, curved lines-increased activity (created with BioRender.com ).

Ficus natalensis extract alleviates Cadmium chloride-induced testicular disruptions in albino rats

BACKGROUND

Cadmium is a potential environmental pollutant with worldwide health problems. Many Ficus species are reported to have an extensive diversity of traditional uses, among them the treatment of reproductive toxicity.

OBJECTIVES

This study set out to evaluate the effect of Ficus natalensis extract on the testicular impairments induced by cadmium chloride (CdCl₂) and investigated the potential mechanisms associated with its treatment.

METHODS

Thus, 40 male albino rats were categorized into 4 groups (n = 10); group I (control), group II (cadmium-treated group) orally received 5 mg/kg/day CdCl₂ for one month, group III (cadmium + Ficus natalensis extract) orally received 5 mg/kg/day CdCl₂ for one month plus 200 mg/kg/day Ficus natalensis extract for another month, and group IV (cadmium + reference drug (mesterolone) orally received 5 mg/kg/day CdCl₂ for one month plus 4.16 mg/kg/day mesterolone for another month.

RESULTS

At the end of experiment, CdCl₂ administration markedly induced histological and histo-morphometric changes with a substantial (p < 0.05) decrease in the sperm count, sperm motility, serum TAC, serum testosterone, downregulation in the mRNA expression levels of testicular 17β-HSD and StAR, in addition to a significant increase in serum TNF-α and testicular MDA level compared to the control group. Conversely, the treatment with Ficus natalensis methanolic extract as well as the reference drug significantly ameliorated the above-mentioned adverse effects induced by CdCl₂.

CONCLUSIONS

Our results suggested that Ficus natalensis extract can attenuate the CdCl₂-induced testicular impairments via inhibiting the oxidative cell damage and inflammation that contributed to CdCl₂ toxicity.

Kaempferol prevents cadmium chloride-induced liver damage by upregulating Nrf2 and suppressing NF-κB and keap1

This study evaluated the protective effect of kaempferol, a natural flavonoid, against cadmium chloride (CdCl₂)-induced liver damage and examined the possible anti-inflammatory and antioxidant mechanisms of protection. Adult male rats were divided into 4 groups (each of 8 rats) as control, kaempferol (50 mg/kg/day orally), CdCl₂ (15 ppm/day), and CdCl₂ (15 ppm/day) + kaempferol (50 mg/kg/day). All treatments were given for 30 days. With no effect on attenuating the reduced food intake, kaempferol significantly increased body weight and lowered serum levels of liver injury markers including bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltransferase 1 (γ-GTT1) in the CdCl₂-treated rats. It also restored normal liver architectures, prevented hepatocyte, loss, and swelling and reduced inflammatory cell infiltration. These effects were associated with a reduction in mitochondrial permeability transition pore, as well as in the expression of cytochrome-c and cleaved caspase-3, markers of mitochondrial damage, and intrinsic cell death. In both the control positive and CdCl₂-treated rats, kaempferol significantly lowered the hepatic levels of reactive oxygen species, malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), Interleukine-6 (IL-6), and the nuclear activity and localization of NF-κB p65. Besides, kaempferol significantly increased the hepatic total and nuclear levels of the nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1, as well as levels of superoxide dismutase (SOD) and reduced glutathione (GSH) but reduced the cytoplasmic protein levels of keap1. In conclusion, the protective effect of kaempferol against CdCl₂-induced hepatic damage is mediated by antioxidant and anti-inflammatory effects driven by upregulating Nrf2/HO-1 axis and suppressing the NF-κB p65 and keap1.

Potentilla anserine L. polysaccharide protects against cadmium-induced neurotoxicity

Cadmium is a toxic metal that can damage the brain and other organs. This study aimed to explore the protective effects of Potentilla anserine L. polysaccharide (PAP) against CdCl2-induced neurotoxicity in N2a and SH-SY5Y cells and in the cerebral cortex of BALB/c mice. In addition, we aimed to identify the potential mechanisms underlying these protective effects. Relative to CdCl2 treatment alone, pretreatment with PAP prevented the reduction in cell viability evoked by CdCl2, decreased rates of apoptosis, promoted calcium homeostasis, decreased ROS accumulation, increased mitochondrial membrane potential, inhibited cytochrome C and AIF release, and prevented the cleavage of caspase-3 and PARP. In addition, PAP significantly decreased the CdCl2-induced phosphorylation of CaMKII, Akt, and mTOR. In conclusion, PAP represents a potential therapeutic agent for the treatment of Cd-induced neurotoxicity, functioning in part via attenuating the activation of the mitochondrial apoptosis pathway and the Ca2+-CaMKII-dependent Akt/mTOR pathway.

Cadmium-induced neurotoxic effects on rat basal forebrain cholinergic system through thyroid hormones disruption

Cadmium (Cd) single and repeated exposure produces cognitive dysfunctions. Basal forebrain cholinergic neurons (BFCN) regulate cognitive functions. BFCN loss or cholinergic neurotransmission dysfunction leads to cognitive disabilities. Thyroid hormones (THs) maintain BFCN viability and functions, and Cd disrupts their levels. However, Cd-induced BFCN damages and THs disruption involvement was not studied. To research this we treated male Wistar rats intraperitoneally with Cd once (1 mg/kg) or repetitively for 28 days (0.1 mg/kg) with/without triiodothyronine (T3, 40 µg/kg/day). Cd increased thyroid-stimulating-hormone (TSH) and decreased T3 and tetraiodothyronine (T4). Cd altered cholinergic transmission and induced a more pronounced neurodegeneration on BFCN, mediated partially by THs reduction. Additionally, Cd antagonized muscarinic 1 receptor (M1R), overexpressed acetylcholinesterase S variant (AChE-S), downregulated AChE-R, M2R, M3R and M4R, and reduced AChE and choline acetyltransferase activities through THs disruption. These results may assist to discover cadmium mechanisms that induce cognitive disabilities, revealing a new possible therapeutic tool.

Cadmium-mediated pancreatic islet transcriptome changes in mice and cultured mouse islets

Type II diabetes mellitus (T2DM) is a multifactorial disease process that is characterized by insulin resistance and impairment of insulin-producing pancreatic islets. There is evidence that environmental exposure to cadmium contributes to the development of T2DM. The presence of cadmium in human islets from the general population and the uptake of cadmium in β-cells have been reported. To identify cadmium-mediated changes in gene expression and molecular regulatory networks in pancreatic islets, we performed next-generation RNA-Sequencing (RNA-Seq) in islets following either in vivo (1 mM CdCl2 in drinking water) or ex-vivo (0.5 μM CdCl2) exposure. Both exposure regiments resulted in islet cadmium concentrations that are comparable to those found in human islets from the general population. 6-week in vivo cadmium exposure upregulates the expression of five genes: Synj2, Gjb1, Rbpjl, Try5 and 5430419D17Rik. Rbpjl is a known regulator of ctrb, a gene associated with diabetes susceptibility. With 18-week in vivo cadmium exposure, we found more comprehensive changes in gene expression profile. Pathway enrichment analysis showed that these secondary changes were clustered to molecular mechanisms related to intracellular protein trafficking to the plasma membrane. In islet culture, cadmium ex vivo significantly induces the expression of Mt1, Sphk1, Nrcam, L3mbtl2, Rnf216 and Itpr1. Mt1 and Itpr1 are known to be involved in glucose homeostasis. Collectively, findings reported here revealed a complex cadmium-mediated effect on pancreatic islet gene expression at environmentally relevant cadmium exposure conditions, providing the basis for further studies into the pathophysiological processes arising from cadmium accumulation in pancreatic islets.

MiR-182-5p/TLR4/NF-κB axis contributes to the protective effect of caffeic acid phenethyl ester against cadmium-induced spleen toxicity and associated damage in mice

Cadmium (Cd) is a toxic heavy metal pollutant that can be accumulated in organs including the spleen, thereby threatening human health. In this study, the effect of caffeic acid phenethyl ester (CAPE, a bioactive component of honeybee propolis) on CdCl2-induced spleen toxicity and underlying mechanisms were examined in mice. Histological examinations revealed that CAPE (10 μmol/kg/day b.w.) could mitigate spleen damage induced by CdCl2 (1.5 mg/kg/day b.w.) in mice. Compared to the mice treated only by CdCl2, CAPE administration increased the body weight while decreasing the spleen weight, spleen Cd content and spleen to body ratio of the CdCl2-treated mice. Western blot and ELISA tests revealed that CAPE suppressed CdCl2-induced inflammation (indicated by the decreases in the levels of inflammatory indictors). TUNEL and Western blot results showed that CAPE suppressed CdCl2-induced apoptosis through reducing the percentage of TUNEL-positive cells and regulating apoptosis factors. The antagonistic effect of CAPE against CdCl2-induced spleen toxicity was realized by increasing miR-182-5p expression to regulate the TLR4/NF-κB pathway. Therefore, CAPE could be a food-derived spleen protector to counteract Cd-induced spleen toxicity through alleviating apoptosis and inflammation via the miR-182-5p/TLR4/NF-κB axis.

Different Routes of Administration Lead to Different Oxidative Damage and Tissue Disorganization Levels on the Subacute Cadmium Toxicity in the Liver

The toxic effects of cadmium (Cd) on hepatic parameters are widely described in the literature. Experimental models often make use of the intraperitoneal route (i.p.) because it is easier to apply, while in the oral route, Cd poisoning in humans is best represented by allowing the metal to pass through the digestive system and be absorbed into the bloodstream. Thus, this study investigated the Cd exposure impact on the liver, by comparing both i.p. and oral routes, both in single dose, in addition to the oral route in fractional doses. Swiss adult male mice received CdCl₂ 1.5 mg/kg i.p., 30 mg/kg oral single dose, and 4.28 mg/kg oral route in fractional doses for 7 consecutive days. Cd bioaccumulation was observed in all animals exposed to Cd. Hepatic concentrations of Ca and Fe increased only in the fractionated oral route. Liver activities of SOD and CAT increased only by oral single dose. GST decreased in all forms of oral administration, while MDA decreased only in i.p. route. Liver weight and HSI increased in the i.p. route, while organ volume increased in all forms of oral administration, and liver density increased in all animals exposed to Cd. In hepatic histomorphometry, the changes were more evident in oral administration, mainly in exposure to metal in a single dose. Thus, the subacute administration of Cd in different routes of administration leads to different changes in liver poisoning.

γ-glutamylcysteine suppresses cadmium-induced apoptosis in PC12 cells via regulating oxidative stress

Cadmium (Cd) is a highly toxic environmental pollutant, leading to the occurrence and development of multiple neurological diseases. γ-glutamylcysteine (γ-GC) is a dipeptide formed by the condensation of l-glutamic acid and l-cysteine, which has antioxidant, anti-inflammatory, and chelating properties. The purpose of this study is to investigate the effect of γ-GC on Cd-induced apoptosis in PC12 cells. PC12 cells were pretreated with or without γ-GC (2 mM or 4 mM) for 2 h and exposed to Cd (10 μM) for 12 h, and survival, apoptosis, and oxidative stress of PC12 cells were detected after different treatments. The results showed that γ-GC significantly inhibited cell viability reduction, apoptosis, and depolarization of mitochondrial transmembrane potential in Cd-treated PC12 cells, as indicated by CCK-8 assay, flow cytometry, TUNEL staining, and JC-1 detection. Western blot showed that γ-GC down-regulated the ratio of Bax/Bcl-2 and the protein levels of cytosolic cytopigment c, cleaved-caspase-9, cleaved-caspase-3, and cleaved-PARP. Mechanistically, γ-GC suppressed Cd-induced ROS production, MDA accumulation, and GSH depletion, and increased the activity of antioxidant enzymes. Cd-induced activation of MAPK and PI3K/Akt signaling pathways were inhibited by γ-GC treatment, while sustained phosphorylation of JNK, p38, or Akt reversed anti-apoptotic effects of γ-GC. These results suggested that γ-GC inhibited Cd-induced apoptosis in PC12 cells through decreasing oxidative stress and inhibiting the activation of MAPK and PI3K/Akt signaling pathways. γ-GC could be used as a potential protective agent against Cd neurotoxicity.

Protective Effects of Bromelain against Cadmium-Induced Pulmonary Intoxication in Rats: A Histopathologic and Cytologic Study

Bromelain is the active substance of pineapple with a variety of therapeutic properties. In this study, the possible protective effects of bromelain were assessed against cadmium acute intratracheal exposure and its bronchopulmonary cytologic and histopathologic consequences. For this purpose, the following treatments were performed on 11 groups of Wistar rats: group 1 was negative control; groups2 and 3 received Cadmium Chloride (CdCl₂) 400 µg/rat intratracheally and sampled after 5 and 10 days, respectively; groups4 and 5received bromelain 20 mg/kg orally (PO) from 14 days before until 5 and 10 days after CdCl₂ instillation, respectively; groups6 and 7received bromelain 40 mg/kg from 14 days before until 5 and 10 days after CdCl₂ instillation, respectively; group 8received bromelain 40 mg/kg for 24 days; groups9 and 10: celecoxib 25 mg/kg PO from 1day before until 5 and 10 days after CdCl₂ instillation, respectively; group 11 received celecoxib for 11 days. Cytologic evaluation of bronchoalveolar lavage fluid revealed that intratracheal cadmium administration resulted in a significant rise in total cell count, epithelial cells, neutrophils, and eosinophils, 5- and 10-days post-exposure. Treatment with bromelain either in low or high doses in cadmium-exposed rats resulted in a significant reduction of neutrophil count. Bromelain treatment could not completely prevent or recover interstitial pneumonia and fibrinous bronchopneumonia in cadmium exposed rats. However, administration of low doses resulted in a significant decrease of semi quantitative histopathologic scores, including pneumonia and cellular infiltration indices. In conclusion, bromelain may help to improve the cytological and histopathological complications following cadmium intoxication in the lungs.

Temporal transcriptomic alterations of cadmium exposed human iPSC-derived renal proximal tubule-like cells

Cadmium is a well-studied environmental pollutant where the kidney and particularly the proximal tubule cells are especially sensitive as they are exposed to higher concentrations of cadmium than other tissues. Here we investigated the temporal transcriptomic alterations (TempO-Seq) of human induced pluripotent stem cell (iPSC)-derived renal proximal tubule-like (PTL) cells exposed to 5 μM cadmium chloride for 1, 2, 4, 8, 12, 16, 20, 24, 72 and 168 h. There was an early activation (within 4 h) of the metal and oxidative stress responses (metal-responsive transcription factor-1 (MTF1) and nuclear factor erythroid-2-related factor 2 (Nrf2) genes). The Nrf2 response returned to baseline within 24 h. The Activator Protein 1 (AP-1) regulated genes HSPA6 and FOSL-1 followed the Nrf2 time course. While the MTF1 genes also spiked at 4 h, they remained strongly elevated over the entire exposure period. The data and cell culture model utilised will be useful in further research aimed at the refinement of safe human exposure limits for cadmium, other metals and their mixtures.

Protective effects of Spirulina (Arthrospira maxima) against toxicity induced by cadmium in Xenopus laevis

Spirulina (Arthrospira maxima) has been recognized as a superfood and nutraceutical by its high nutritional value and the benefits of its consumption; it is an important source of lipids, proteins, vitamins, minerals, and antioxidants. It is known that spirulina has positive effects on the toxicity induced by pharmaceuticals and metals. Heavy metals such as cadmium, frequently used in industrial activities, are continuously detected in water bodies and can generate adverse effects on aquatic organisms even at low concentrations. This study aimed to evaluate the protective effect of spirulina (Arthrospira maxima) against the toxic effects induced by cadmium in the early life stages of Xenopus laevis. Twenty Xenopus laevis embryos were exposed to five different treatments on triplicate, control, cadmium (CdCl₂ 24.5 μg L^-1) and three spirulina mixtures Cd + S 1 (24.5 μg L^-1 CdCl₂ + 2 mg L^-1 spirulina), Cd + S 2 (24.5 μg L^-1 CdCl₂ + 2 mg L^-1 spirulina), Cd + S 3 (24.5 μg L^-1 CdCl₂ + 10 mg L^-1 spirulina); after 96 h of exposure: Malformations, mortality and length were evaluated; also, after 192 h, lipid peroxidation (LPX), superoxide dismutase (SOD) and catalase (CAT) were determined. All spirulina treatments decreased mortality from 34 to 50% and reduced malformations on incidence from 36 to 68%. Treatment Cd + S 3 decreased growth inhibition significantly. Spirulina treatment Cd + S 2 decreased lipidic peroxidation and antioxidant activity; these results suggest that spirulina (Arthrospira maxima) can decrease the mortality, frequency of malformations, the severity of malformations, growth inhibition, and oxidative damage induced by cadmium in Xenopus laevis embryos.

Effect of combined exposure to silica nanoparticles and cadmium chloride on female zebrafish ovaries

Silica nanoparticles (SiNPs) and cadmium chloride (CdCl₂) are two important environmental pollutants. In previous research, found that SiNPs in zebrafish larvae can amplify the cardiovascular damage caused by cadmium. Whether SiNPs in the ovaries can amplify the adverse effects of cadmium on the zebrafish ovaries is worth studying problem. In this study, sexually mature female zebrafish were used as model organisms and exposed to 1 μmol/L CdCl₂ and/or 25 μg/mL SiNPs for 30 days. The results showed that the structure and function of ovaries in the sole and combined exposure groups changed significantly, resulting in reduced ovarian quality, decreased number of mature oocytes, and the development of malformed offspring. A deep-sequencing analysis showed that organisms' lipid metabolism and transportation, estrogen metabolism, and response to the maturation, meiosis, and vitellogenin synthesis of oocytes were significantly affected by single exposure or combined exposure. These findings provide further insights into the harm of cooperation of CdCl2 and/or SiNPs to the aquatic ecosystems.

Acclimation of cadmium-induced genotoxicity and oxidative stress in mung bean seedlings by priming effect of phytohormones and proline

In this research, eight local mung bean (Vigna radiata) varieties were analyzed for their performance against two levels of CdCl2 solution (0.3 and 0.5 mM) alone and priming with gibberellic acid (GA3) (100 μM), salicylic acid (SA) (50 μM) and proline (5 mM) solution prior to Cd exposure. Mung bean seedlings were analyzed for disturbance in cytological, morphological, biochemical and enzymatic parameters under cadmium stress. For cytological studies, 48 h grown mung bean seedlings root tips were used to prepare slides and studied for percent mitotic index (MI%) and to calculate percent C-mitosis, laggard, sticky and fragmented chromosomes, pictures were captured by a Nikon camera (DS-Fi 1 Japan) attached with a microscope. One-week grown mung seedlings were studied for growth traits, malondialdehyde (MDA), protein, proline and antioxidant enzymes. ANOVA and DMR test of this research revealed that all the tested mung bean varieties and treatments were significantly different regarding mitotic index and number of chromosomal aberrations. Both the Cd treatments exhibited increased total chromosomal aberrations with different types and a maximum decrease in MI%. In pretreated samples, GA3, SA and proline serve as mitigating agents that reduce mutagenic effects of Cd in mung bean by increasing MI% and decreasing chromosomal aberrations as compared to non-pretreated samples. Both the Cd treatments showed a decrease in all growth traits. Total proteins were also found to be significantly reduced in a dose-dependent manner in all genotypes. Cd treatment increased the activities of all antioxidant enzymes tested. Cd caused oxidative damage as indicated by elevated levels of MDA content in treated samples in comparison to control. Proline content levels were also high in Cd treated seedlings indicating stress. Results demonstrated that pretreatment with phytohormones and proline before Cd were found to improve all morphological parameters, by altering antioxidant enzymes activities along with a decrease in MDA and proline contents as well. It was further noticed that the performance of GA3 was better at 0.3 mM Cd treatment while SA was found to be a good mitigating agent at 0.5 mM Cd stress in all tested mung bean varieties. This research concluded less deleterious effects of Cd on AZRI-2006 while more sensitivity to NM-51 towards Cd. Priming with phytohormones and proline is a user-friendly, economical, and simple mitigation strategy to reduce Cd toxicity in plants and get better yield from contaminated lands.

Evaluation of Cadmium Chloride-Induced Toxicity in Chicks Via Hematological, Biochemical Parameters, and Cadmium Level in Tissues

Cadmium is a heavy metal and a non-biodegradable environmental contaminant, and its omnipresence ensures its recurrent exposure to humans and animals. Its intake by chicks leads to fatal implications. Cadmium chloride (CdCl₂) because of its bio-accumulative nature is an emerging threat to the poultry industry as well as to the humans which consumes these cadmium-intoxicated chickens. In the current study, the target was to elucidate the toxic effects of CdCl₂on body weight, hematological, and biochemical parameters as well as its bioaccumulation in different organs of broiler chicks. Various concentrations of CdCl₂ (0, 12, 24, 38, and 48 mg/kg body weight) were administered orally to five groups (A, B, C, D, and E) of broiler chicks, respectively. The biometric screening of the exposed birds was carried out by hematological parameters such as packed cell volume (PCV), total erythrocyte count (TEC), mean corpuscular hemoglobin concentration (MCHC), total protein, white blood cells (WBC), and hemoglobin (Hb), as well as biochemical parameters superoxide dismutase (SOD), low-density lipoprotein (LDL), glutathione peroxidase (GPx), and high-density lipoprotein (HDL) with commercially available kits. Metal accumulation in different organs was detected using atomic absorption spectrophotometer. The compound exposure produced a varied impact on broiler birds. Hematological parameters showed a significant decrease except for WBC. Biochemical parameters also decreased significantly in a dose-dependent manner. However, it was revealed that the body weight of chickens was not affected considerably after CdCl₂ exposure. A direct relationship was detected between the accumulation of metal within tissues (lungs, heart, and flesh) and exposure frequency. It can be deduced that an increase in Cd deposition in tissues may lead to an alteration in hematological-biochemical markers which may significantly contribute to systemic toxicity in broilers.

The electrophysiological effects of cadmium on Retzius nerve cells of the leech Haemopis sanguisuga

Cadmium is considered one of the most toxic heavy metals which can cause cytotoxicity in multiple organs including the brain. Despite many studies over the past decades, the cellular and molecular mechanisms underlying its neurotoxicity remain unclear. The present study was designed to examine the acute effects of cadmium chloride (CdCl₂) on the electrical activity of the Retzius nerve cells of leech Haemopis sanguisuga using electrophysiological techniques. CdCl₂, in concentrations of 10-100 μM, produced a dose- and time-dependent depolarization of Retzius neurons, paralleled by an increase in firing frequency and action potential duration. To examine potential mechanisms, we studied the effects of cadmium on the outward potassium current upon depolarization using a point microelectrode voltage-clamp technique. Reduction of the fast, and partial inhibition of the slow outward current were observed after adding 50 and 100 μM CdCl₂ in the external fluid. The present results support the view that the effect of cadmium on the outward potassium channel may be a potential contributing mechanism for cadmium-induced neurotoxic damage. The proposed mechanism of cadmium action on the electrical properties of leech Retzius neurons might have broader significance concerning not only the leeches but vertebrate brains as well.

C-myc promotes miR-92a-2-5p transcription in rat ovarian granulosa cells after cadmium exposure

Cadmium (Cd) can induce ovarian injury by microRNAs (miRNAs), however, the molecular mechanism of miRNAs after Cd exposure have not known. In this study, 56-day-old adult female Sprague-Dawley (SD) rats were injection with PMSG, after 48 h, ovarian granulosa cells (GCs) were extracted and cultured for 24 h, then treated with 0, 2.5, 5, 10 and 20 μM Cd for 24 h. The results showed that expression levels of miR-92a-2-5p (upregulated) and Bcl2 (downregulated) changed significantly after Cd exposure. The messenger RNA (mRNA) and protein expression levels of DNMT1, DNMT3A, and DNMT3B had changed, but no obvious differences were found in miR-92a-2-5p single site methylation. The transcription factors C-MYC (upregulated), E2F1 (downregulated), and SP1 (downregulated), which target miRNAs significantly changed after exposure to Cd. The human ovarian GC tumor line (COV434) was used to knocked down C-myc, and the expression of miR-92a-2-5p was downregulated in the COV434-C-myc + 10 μM Cd group compared with COV434 cells. The N6-methyladenosine (m6A) methylation modification levels of long noncoding RNA (lncRNA) MT1JP and lncRNA CDKN2B-AS, which regulate miR-92a-2-5p were detected. In the 10 μM Cd group, m6A methylation levels at MT1JP-84, CDKN2B-AS-257, and CDKN2B-AS-329 were reduced. In summary, after Cd exposure, expression of miR-92a-2-5p, which targets the antiapoptotic gene Bcl2, was upregulated, which may be primarily related to upregulation of C-myc. MiR-92a-2-5p promoter DNA methylation may has no obvious effect on miR-92a-2-5p. Otherwise, the role of m6A methylation modified lncRNA MT1JP and lncRNA CDKN2B-AS in the regulation of miR-92a-2-5p needs further study.

Cadmium-induced dysfunction of the blood-brain barrier depends on ROS-mediated inhibition of PTPase activity in zebrafish

Increasing evidence has demonstrated that cadmium accumulation in the blood increases the risk of neurological diseases. However, how cadmium breaks through the blood-brain barrier (BBB) and is transferred from the blood circulation into the central nervous system is still unclear. In this study, we examined the toxic effect of cadmium chloride (CdCl₂) on the development and function of BBB in zebrafish. CdCl₂ exposure induced cerebral hemorrhage, increased BBB permeability and promoted abnormal vascular formation by promoting VEGF production in zebrafish brain. Furthermore, in vivo and in vitro experiments showed that CdCl₂ altered cell-cell junctional morphology by disrupting the proper localization of VE-cadherin and ZO-1. The potential mechanism involved in the inhibition of protein tyrosine phosphatase (PTPase) mediated by cadmium-induced ROS was confirmed with diphenylene iodonium (DPI), a ROS production inhibitor. Together, these data indicate that BBB is a critical target of cadmium toxicity and provide in vivo etiological evidence of cadmium-induced neurovascular disease in a zebrafish BBB model.

Investigating the underlying mechanism of cadmium-induced plant adaptive response to genotoxic stress

Plants as sessile organisms have developed some unique strategies to withstand environmental stress and adaptive response (AR) is one of them. In the present study Cadmium (Cd)-induced AR was evaluated to ameliorate the genotoxicity of a known chemical mutagen ethyl methanesulphonate (EMS) based on cytotoxicity, genotoxicity and oxidative stress in two model plant systems Allium cepa L. and Vicia faba L. Priming the plants with cadmium chloride (CdCl₂, 25 and 50 μM) reduced the genotoxicity of EMS (0.25 mM). Cd-induced AR was evident by the magnitude of adaptive response (MAR) values calculated for cytotoxicity, genotoxicity and biochemical parameters. In addition the involvement of some major metabolic pathways and epigenetic modifications in AR was investigated. Metabolic blockers of protein kinase cascades, DNA repair, oxidative stress and de novo translation interfered with the adaptive response implying their role in AR whereas, inhibitors involved in post-replication repair and autophagy were ineffective implicating that they probably have no role in the AR studied. Moreover to find the role of DNA methylation in AR, methylation-sensitive comet assay was carried out. Simultaneously 5-methyl- 2'-deoxycytidine (5mdC) levels were quantified by HPLC (high performance liquid chromatography). AR was eliminated in cells treated with a demethylating agent, 5-aza- 2'deoxycytidine (AZA). Results implied a contribution of DNA hypermethylation. To the best of our knowledge this is a first report correlating DNA methylation to Cd-induced adaptive response in plants undergoing genotoxic stress.

Single-cell RNA sequencing of mouse neural stem cell differentiation reveals adverse effects of cadmium on neurogenesis

Cadmium (Cd) is a toxic heavy metal and widely exists in the environment. Extensive studies have revealed that Cd exposure can elicit neurotoxicity and potentially interfere with neurogenesis. However, underlying mechanisms by which Cd exposure affects neurogenesis remain unclear. In this study, we performed single-cell RNA sequencing (scRNA-seq) of the differentiated mixture from neonatal mouse Neural Stem Cells (mNSCs) that were exposed to Cd for 24 h and differentiated for 7 days. Our results showed that Cd exposure led to an increase in the differentiation of NSCs into astrocytes while a decrease into neurons. Besides, Cd induced subtype-specific response and dysregulated cell-to-cell communication. Collectively, our scRNA-seq data suggested that Cd had toxic effects on NSCs differentiation at the single-cell level, which offered insight into the potential molecular mechanism of Cd on neurogenesis. Furthermore, our findings provided a new method for assessing the neurodevelopmental toxicity of environmental pollutants.

Underlying mechanisms of cytotoxicity in HepG2 hepatocarcinoma cells exposed to arsenic, cadmium and mercury individually and in combination

BACKGROUND

Toxicity data regarding combinational exposure of humans to arsenic, cadmium and mercury is scarce. Although hepatotoxicity has been reported, limited information is available on their mechanistic underpinnings. The cytotoxic mechanisms of these metals were determined in HepG2 hepatocarcinoma cell lines after individual and combinational exposure.

METHODS

HepG2 cells were exposed to heavy metals (sodium arsenite, cadmium chloride, and mercury chloride) individually or in combination for 24 h, after which cell density, mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS), reduced glutathione (GSH), adenosine triphosphate (ATP) and caspase-3/7 activity was assessed.

RESULTS AND DISCUSSION

Cadmium (IC₅₀ = 0.43 mg/L) and the combination (0.45 mg/L, arsenic reference) were most cytotoxic, followed by arsenic (6.71 mg/L) and mercury (28.23 mg/L). Depolarisation of the ΔΨm and reductions in ROS, GSH and ATP levels occurred. Arsenic, cadmium and the combination increased caspase-3/7 activity, while mercury reduced it.

CONCLUSION

The combination produced a greater, albeit mechanistically similar, cytotoxicity compared to individual metals. Cytotoxicity was dependent on altered mitochondrial integrity, redox-status, and bioenergetics. Although the combination's cytotoxicity was associated with caspase-3/7 activity, this was not true for mercury. Heavy metal interactions should be assessed to elucidate molecular underpinnings of cytotoxicity.

Usage of atomic force microscopy for detection of the damaging effect of CdCl2 on red blood cells membrane

The possibility of detecting the damaging effect of cadmium salts on red blood cells (RBC) membrane by atomic force microscopy and light microscopy was studied. White wistar rats RBC were incubated with cadmium chloride in concentrations of 1 μg/l, 10 μg/l, 100 μg/l, and 1000 μg/l for the research. A comparison of sample preparation methods proposed by other authors in previous studies is made. The optimal method that does not significantly affect the change in the morphological features of the cell is selected. The quantitative assessment of damaged and destroyed RBC depending on the concentration of cadmium was performed by optical microscopy. The study showed that CdCl₂ has a damaging effect on the RBC membrane, which leads to the formation of non-specific cell forms. A comparative assessment was made between the methods of optical microscopy and atomic force microscopy for the suitability of studying the morphological characteristics of abnormal forms of the RBC. It is shown that the method of atomic force microscopy allows registering morphological changes in the RBC that cannot be registered by optical microscopy. It is pointed that CdCl₂ has effect on destruction of the RBC and the formation of specific bulges on the RBC membrane. Influence of CdCl₂ on the RBC mechanical properties was studied using atomic force microscopy. The possibility of using atomic force microscopy in studies of morphology and mechanical properties of the RBC under toxicity effect of cadmium is shown.

Cadmium chloride-induced transgenerational neurotoxicity in zebrafish development

As an important environmental pollutant, the heavy metal cadmium has a significant negative impact on the stability of the ecological environment and on organismal health. Previous studies have shown that cadmium chloride can damage the nervous, skeletal, endocrine, and reproductive systems, but to our knowledge, the effects of cadmium on the behavior, neurotransmitter levels, and neuronal development in the offspring of exposed animals have not been reported. In the present study, sexually-mature zebrafish were exposed to cadmium chloride at different concentrations for 60 days, and in this background, behavior, neurotransmitters level, neuro-development and neurotransmitter metabolism was investigated in the F1 offspring. The results showed that exposure of the parental zebrafish to cadmium chloride resulted swimming speed and distance of F1 offspring significantly reduced; the levels of neurotransmitters, such as dopamine, serotonin, and acetylcholine is disrupted. neuro-development and neurotransmitter metabolism related genes expression pattern was altered, which cause zebrafish F1 offspring developmental neurotoxicity. These findings provide further insights into the harm posed by cadmium chloride to the aquatic ecosystems.

The Non-hormonal Male Contraceptive Adjudin Exerts its Effects via MAPs and Signaling Proteins mTORC1/rpS6 and FAK-Y407

Adjudin, 1-(2,4-dichlorobenzyl)-1H-indazole-3-carbohydrazide (formerly called AF-2364), is a nonhormonal male contraceptive, since it effectively induces reversible male infertility without perturbing the serum concentrations of follicle stimulating hormone (FSH), testosterone, and inhibin B based on studies in rats and rabbits. Adjudin was shown to exert its effects preferentially by perturbing the testis-specific actin-rich adherens junction (AJ) at the Sertoli-spermatid interface known as apical ectoplasmic specialization (apical ES), thereby effectively inducing spermatid exfoliation. Adjudin did not perturb germ cell development nor germ cell function. Also, it had no effects on Sertoli cell-cell AJ called basal ectoplasmic specialization (basal ES), which, together with tight junction constitute the blood-testis barrier (BTB), unless an acute dose of adjudin was used. Adjudin also did not perturb the population of spermatogonial stem cells nor Sertoli cells in the testis. However, the downstream signaling protein(s) utilized by adjudin to induce transient male infertility remains unexplored. Herein, using adult rats treated with adjudin and monitored changes in the phenotypes across the seminiferous epithelium between 6 and 96 h in parallel with the steady-state protein levels of an array of signaling and cytoskeletal regulatory proteins, recently shown to be involved in apical ES, basal ES and BTB function. It was shown that adjudin exerts its contraceptive effects through changes in microtubule associated proteins (MAPs) and signaling proteins mTORC1/rpS6 and p-FAK-Y407. These findings are important to not only study adjudin-mediated male infertility but also the biology of spermatogenesis.

Combined toxicity of silica nanoparticles and cadmium chloride on the cardiovascular system of zebrafish (Danio rerio) larvae

Silica nanoparticles (SiNPs) and cadmium are major environmental pollutants that have severe detrimental effects on living organisms. Recent studies have demonstrated that the combined exposure of SiNPs and heavy metals is more toxic than individual exposure. However, studies on the effects of the combined exposure of SiNPs and cadmium, on the cardiovascular system are rare. In this study, zebrafish (Danio rerio) embryos were exposed to a combination of SiNPs and experimentally safe concentrations CdCl₂ for studying the alterations in heart morphology, heart rate, apoptosis, and vascular endothelial cells. The results demonstrated that the detrimental effects of SiNPs+CdCl₂ exposure on the heart rate and vascular endothelial cells were more severe than those following exposure to SiNPs or CdCl₂ alone. Gene expression analysis revealed that apoptosis and inflammation could be the major pathways underlying the toxicity caused by the combined exposure of SiNPs and CdCl₂.

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.

Heme oxygenase 1 plays a crucial role in swamp eel response to oxidative stress induced by cadmium exposure or Aeromonas hydrophila infection

Oxidative stress contributes a lot to initiation and progression of pathological conditions. Heme oxygenase 1 (HO1), a cytoprotective enzyme, is usually upregulated to alleviate oxidative stress in vivo. The function of teleost HO1 in the response to oxidative stress induced by heavy metal exposure and in pathogenic bacterial infection remains uncertain. In the present study, both complementary DNA and genomic sequence of a HO1-like gene cloned from the liver of swamp eel (Monopterus albus) are reported. Sequence analysis showed that the putative amino acid sequence contained a conserved heme oxygenase signature and displayed higher similarity to HO1 genes of other teleosts. Expression profile of swamp eel HO1 was investigated in healthy tissues and in tissues following stimulation with pathogenic bacteria (Aeromonas hydrophila) or cadmium chloride (CdCl₂) exposure. Results demonstrated that HO1 messenger RNA (mRNA) was highly expressed in the liver and relatively less in other tissues. Bacterial infection with A. hydrophila significantly changed HO1 mRNA expression in the liver, spleen, and kidney, and the mRNA expression of HO1 and Nrf2 in the liver was elevated after the fish were exposed to CdCl₂. Subsequently, the swamp eel HO1 was subcloned into a pET28a expression vector and transformed into Escherichia coli BL21 (DE3). Recombinant HO1 (rHO1) was successfully induced by 0.1 mmol/l IPTG and purified by Ni-NTA His Bind Resin purification system. To determine whether the rHO1 could confer stress tolerance in vitro, the viability of control and HO1-expressing E. coli under CdCl₂ stress was compared by spot assay. The rHO1 protein significantly increased survival rates of the bacterial hosts. To evaluate whether intraperitoneal injection with rHO1 protected the liver of swamp eel against A. hydrophila-induced oxidative stress, mRNA expression of HO1, Nrf2, hepcidin, and IL-1β as well as the oxidative stress-related parameters (ROS and total antioxidant capacity (T-AOC)) in the liver were examined. The results showed that exogenous rHO1 could significantly upgrade the mRNA expression of HO1 and hepcidin, coupled with increased ROS and T-AOC levels. However, Nrf2 and IL-1β expression levels were significantly downregulated and upregulated, respectively. These results suggested that HO1 should not only play a protective role in oxidative stress response and its adverse effects deserved further investigation.

Development of a Reduced-Volume Acute Lethality Toxicity Test for Hyalella azteca

Effects-directed analysis (EDA) is used to identify the principal toxic components within a complex mixture using iterative steps of chemical fractionation guided by bioassay results. Bioassay selection can be limited in EDA because of the volume requirements for many standardized test methods, and therefore, a reduced-volume acute toxicity test that also provides whole-organism responses is beneficial. To address this need, a static, 7-d, water-only, reduced-volume method (50 mL, 10 organisms) was developed for Hyalella azteca that substantially decreases the volume requirements of standard-volume acute test exposures (200-500 mL of test solution, 15-20 organisms) while maintaining water quality and meeting control survival criteria. Standard- and reduced-volume methods were compared by conducting concurrent toxicity tests with 2 inorganic toxicants (KCl and CdCl₂ ) and 2 organic mixtures of naphthenic acid fraction components (NAFCs) to evaluate test performance. There was no difference between methods when comparing the median lethal concentrations (LC50s) for KCl and both NAFC mixtures (p > 0.05). The LC50s for CdCl₂ were statistically different (p = 0.0002); however, this was not considered biologically meaningful because the difference between LC50s was <2-fold. In conclusion, the reduced-volume H. azteca test method generated results comparable to standard-volume test methods and is suitable for use in situations where limited testing material is available, such as when conducting EDA. Environ Toxicol Chem 2020;39:2221-2227. © Her Majesty the Queen in Right of Canada 2020. Reproduced with the permission of the Minister of Environment and Climate Change Canada.

Hypomethylation of LINE-1 retrotransposons is associated with cadmium-induced testicular injury

Retrotransposons, as vital regulator of male fertility, are essential for spermatogenesis. Cadmium (Cd) is an environmental toxicant and endocrine disruptor, targeting the reproductive system. Growing evidence shows that Cd exposure can induce male infertility in mammals. In this study, we generated a male C57BL/6 J mice model with consecutive 35 days cadmium chloride (CdCl₂) in different concentrations of 0, 0.25, 0.5, 1.0, and 2.0 mg/kg. The results indicated that 1.0 and 2.0 mg/kg CdCl₂ significantly affected the body weight. Meanwhile, the highest dose group with 2.0 mg/kg CdCl₂ presented low fertility. Furthermore, the expression of retrotransposon mRNA was markedly increased in the higher doses group. We examined methylcytosine (mC) levels of the three active LINE-1 subfamilies TfI, A, and GfII in testis. Conclusively, Cd exposure probably undermines the male mice fertility by disrupting DNA methylation to regulate the retrotransposons. Further studies are required for identifying whether retrotransposon activation has any significant impacts on genome structure, stability, and expression in Cd-induced testicular injury, laying foundation for the treatment for male infertility.

MicroRNA-101 inhibits cadmium-induced angiogenesis by targeting cyclooxygenase-2 in primary human umbilical vein endothelial cells

Exposure to toxic metal contaminants, such as cadmium compounds (Cd²⁺), has been shown to induce adverse effects on various organs and tissues. In particular, blood vessels are severely impacted by Cd²⁺ exposure, which may lead to cardiovascular diseases (CVDs). According to previous studies, CVDs are associated with increased cyclooxygenase 2 (COX-2) levels. However, the mechanisms by which CdCl₂-induced COX-2 overexpression leads to cardiovascular dysfunction remain unclear. Herein, we show that the relative gene expressions of VEGF and PTGS2 (COX-2 encoding gene) are positively correlated in CVDs patients. Moreover, we demonstrate that the in vitro administration of CdCl₂ induces cytotoxicity and endoplasmic reticulum (ER) stress in primary human umbilical vein endothelial cells (HUVECs). The induction of ER stress and the overexpression of COX-2 in CdCl₂-treated cells alters the protein level of vascular endothelial growth factor (VEGF), resulting in abnormal angiogenesis and increased cytotoxicity. At the pre-transcription level, the inhibition of ER stress by siGRP78 (a key mediator of ER stress) can restore normal angiogenesis in the CdCl₂-exposed cells. Meanwhile, at the transcription level, the adverse effects of CdCl₂ exposure may be reversed via genetic modification with siRNA (siPTGS2) or by using phytochemical inhibitors (parthenolide, PN) of COX-2. Finally, at the post-transcription level, COX-2 expression may be restricted by the binding of microRNA-101 (miR-101) to the 3'-UTR of PTGS2 mRNA. The use of mimic miR-101 (mi101) to induce the expression of miR-101 eventually leads to reduced COX-2 protein levels, relieved ER stress, and less abnormal angiogenesis and cytotoxicity of CdCl₂-exposed primary HUVECs. Overall, our results suggest that CdCl₂-induced abnormal angiogenesis is mediated by miR-101/COX-2/VEGF-axis-dependent ER stress, and that cardiovascular dysfunction may be controlled by manipulating COX-2 at the pre-transcription, transcription, and post-transcription levels.