Molybdenum nanoparticles-induced cytotoxicity, oxidative stress, G2/M arrest, and DNA damage in mouse skin fibroblast cells (L929)

The mediating role of accelerated biological aging in the association between blood metals and cognitive function

Aging is a key risk factor in cognitive diseases. Recently, metal exposures were found associated with both biological aging and cognitive function. Here, we aim to evaluate the associations of blood metals with cognitive function and the mediated effect of biological aging. Fourteen metals were detected and biological age was calculated through Klemera and Doubal method among 514 adults in Beijing, China. The generalized linear models indicated that the copper (Cu), molybdenum (Mo), and strontium (Sr) were positively associated with biological aging [βCu (95% CI): 12.76 (9.26, 16.27); βMo (95% CI): 1.50 (0.15, 2.85)], and βSr (95% CI): 1.86 (0.68, 3.03)], while vanadium (V) was inversely related to biological aging [βV (95% CI): -0.76 (-1.48, -0.05)]. Subsequently, Cu, lead (Pb), selenium (Se), and biological aging were associated with cognitive function and further mediation analyses confirmed that biological aging partially mediated (33.98%, P = 0.019) the association of Cu and cognitive function. Additionally, we constructed a lifestyle index that implied the modifiable healthy lifestyle could slow aging to attenuate the detrimental effect of metals on cognition. Our findings provide insights into the potential pathways linking multiple metals exposure to aging and cognition and underscore the importance of adopting healthy lifestyles.

Iron oxide nanoparticles induced cytotoxicity, oxidative stress, cell cycle arrest, and DNA damage in human umbilical vein endothelial cells

BACKGROUND

Nanotechnology and material science have developed enormously fast in recent years. Due to their excellent magnetic properties, iron oxide nanoparticles (IONPs) have been broadly applied in the field of bioengineering and biomedical. Thus, it is important to evaluate the safety issues and health effects of these nanomaterials. The present investigation was aimed to evaluate the adverse effects of IONPs on human umbilical vein endothelial cells (HUVECs).

METHODS

The cytotoxic potential of IONPs was assessed by MTT and neutral red uptake (NRU) assays. The impact of IONPs on oxidative stress markers (glutathione (GSH) and lipid peroxidation (LPO)), reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP) was also examined. Furthermore, the toxic effect of IONPs was quantified by assessing DNA damage, cell cycle arrest, and apoptosis by quantitative real time PCR.

RESULTS

We found that IONPs induce a dose-dependent cytotoxicity on HUVECs with IC50 value of 79.13 μg/mL. The results also displayed that IONPs induce oxidative stress, ROS production, and mitochondrial membrane dysfunction. The comet assay results exhibited IONPs induces DNA damage in HUVECs. We found significant cell cycle arrest at SubG1 phase in treated cells and consequent cell death was evidenced by microscopic analysis. Moreover, IONPs display substantial up-regulation of pro-apoptotic genes and down-regulation of anti-apoptotic gene evidenced by real time qPCR.

CONCLUSION

Overall, our results clearly demonstrated that IONPs have the potential to induce cytotoxicity, DNA damage, cell cycle arrest, and apoptosis in HUVECs mediated through oxidative stress and ROS production. Thus, IONPs are cytotoxic and it should be handled with proper care.

Aging of Copper Nanoparticles in the Marine Environment Regulates Toxicity for a Coastal Phytoplankton Species

Environmental conditions in aquatic ecosystems transform toxic chemicals over time, influencing their bioavailability and toxicity. Using an environmentally relevant methodology, we tested how exposure to seawater for 1-15 weeks influenced the accumulation and toxicity of copper nanoparticles (nano-Cu) in a marine phytoplankton species. Nano-Cu rapidly agglomerated in seawater and then decreased in size due to Cu dissolution. Dissolution rates declined during weeks 1-4 and remained low until 15 weeks, when the large agglomerates that had formed began to rapidly dissolve again. Marine phytoplankton species were exposed for 5-day periods to nano-Cu aged from 1 to 15 weeks at concentrations from 0.01 to 20 ppm. Toxicity to phytoplankton, measured as change in population growth rate, decreased significantly with particle aging from 0 to 4 weeks but increased substantially in the 15-week treatment due apparently to elevated Cu dissolution of reagglomerated particles. Results indicate that the transformation, fate, and toxicity of nano-Cu in marine ecosystems are influenced by a highly dynamic physicochemical aging process.

Induction of cytotoxic effects and changes in DNA methylation-related gene expression in a human fibroblast cell line by the metal-organic framework [H2NMe2]3 [Tb(III)(2,6 pyridinedicarboxylate)3] (Tb-MOF)

Lanthanide metal-organic frameworks (lanthanide MOFs) may be utilized for a variety of environmental and human health applications due to their luminescent properties and high thermal and water stability. However, the cytotoxic and epigenetic effects produced in human cells are not known. Therefore, we evaluated the cytotoxic effects, internalization, and changes in the mRNA abundance of DNA methylation and demethylation enzymes by exposing human fibroblast cells to a metal-organic framework [H₂NMe₂]₃ [Tb(III)(2,6 pyridinedicarboxylate)₃] (Tb-MOF). For this purpose, the cells were exposed to six concentrations (0.05 to 1.6 mg/mL) of Tb-MOF for 48 h. Field emission electron microscopy coupled to linear energy dispersive spectroscopy (FESEM‒EDS) and confocal microscopy analysis were performed. The cytotoxicity was determined with crystal violet and MTT assays. The results demonstrated the internalization of Tb-MOF at concentrations as low as 0.05 mg/mL, as well as concentration-dependent toxicity. Additionally, we detected significant changes in the gene expression levels of DNA methyltransferases and demethylases due to the presence of Tb-MOF, suggesting that Tb-MOF could generate epigenetic changes even at low concentrations. The results of our study may establish a foundation for future research attempting to develop and apply secure nanomaterials (e.g., MOFs) to minimize damage to the environment and human health.

Associations between multiple metals exposure and biological aging: Evidence from the Dongfeng-Tongji cohort

Aging is related to a progressive decline in physiological functions and is affected by environmental factors. Metal exposures are linked with many health effects, but have poorly understood associations with aging. In this study, a total of 33,916 participants from the Dongfeng-Tongji cohort were included to establish biological age (BA) predictors by using recent advanced algorithms, Klemera and Doubal method (KDM) and Mahalanobis distance. Two biological aging indexes (BAIs), recorded as KDM-accel [the residual from regressing KDM-BA on chronological age] and physiological dysregulation (PD), were separately defined and tested on their associations with mortality by using Cox proportional hazard models. Among 3320 subjects with laboratory determinations of 23 metals in plasma, the individual and overall associations between these metals and BAIs were evaluated by using multiple-linear regression and weighted quantile sum (WQS) models. Both BAIs were prospectively associated with all-cause mortality among the whole participants [KDM-accel: HR(95%CI) = 1.23(1.18, 1.29); PD: HR(95%CI) = 1.37(1.31, 1.42)]. Each 1-unit increment in ln-transformed strontium and molybdenum were cross-sectionally associated with a separate 0.71- and 0.34-year increase in KDM-accel, and each 1 % increment in copper, rubidium, strontium, cobalt was cross-sectionally associated with a separate 0.10 %, 0.10 %, 0.09 %, 0.02 % increase in PD (all FDR < 0.05). The WQS models observed mixture effects of multi-metals on aging, with a 0.20-year increase in KDM-accel and a 0.04 % increase in PD for each quartile increase in ln-transformed concentrations of all metals [KDM-accel: β(95%CI) = 0.20(0.08, 0.32); PD: β(95%CI) = 0.04(0.02, 0.06)]. Our findings revealed that plasma strontium, molybdenum, copper, rubidium and cobalt were associated with accelerated aging. Multi-metals exposure showed mixture effects on the aging process, which highlights potential preventative interventions.

Copper Oxide Nanoparticles Exhibit Cell Death Through Oxidative Stress Responses in Human Airway Epithelial Cells: a Mechanistic Study

Copper oxide nanoparticles (CuONPs) are purposefully used to inhibit the growth of bacteria, algae, and fungi. Several studies on the beneficial and harmful effects of CuONPs have been conducted in vivo and in vitro, but there are a few studies that explain the toxicity of CuONPs in human airway epithelial cells (HEp-2). As a result, the purpose of this study is to look into the dose-dependent toxicity of CuONPs in HEp-2 cells. After 24 h of exposure to 1-40 µg/ml CuONPs, the MTT and neutral red assays were used to test for cytotoxicity. To determine the mechanism(s) of cytotoxicity in HEp-2 cells, additional oxidative stress assays (LPO and GSH), the amount of ROS produced, the loss of MMP, caspase enzyme activities, and apoptosis-related genes were performed using qRT-PCR. CuONPs exhibited dose-dependent cytotoxicity in HEp-2 cells, with an IC₅₀ value of ~ 10 μg/ml. The morphology of HEp-2 cells was also altered in a dose-dependent manner. The involvement of oxidative stress in CuONP-induced cytotoxicity was demonstrated by increased LPO levels and ROS generation, as well as decreased levels of GSH and MMP. Furthermore, activated caspase enzymes and altered apoptotic genes support CuONPs' ability to induce apoptosis in HEp-2 cells. Overall, this study demonstrated that CuONPs can cause apoptosis in HEp-2 cells via oxidative stress; therefore, CuONPs may pose a risk to human health and should be handled and used with caution.

Cytotoxicity of Metal-Based Nanoparticles: From Mechanisms and Methods of Evaluation to Pathological Manifestations

Metal-based nanoparticles (NPs) are particularly important tools in tissue engineering-, drug carrier-, interventional therapy-, and biobased technologies. However, their complex and varied migration and transformation pathways, as well as their continuous accumulation in closed biological systems, cause various unpredictable toxic effects that threaten human and ecosystem health. Considerable experimental and theoretical efforts have been made toward understanding these cytotoxic effects, though more research on metal-based NPs integrated with clinical medicine is required. This review summarizes the mechanisms and evaluation methods of cytotoxicity and provides an in-depth analysis of the typical effects generated in the nervous, immune, reproductive, and genetic systems. In addition, the challenges and opportunities are discussed to enhance future investigations on safer metal-based NPs for practical commercial adoption.

Possible Ameliorative Effects of the Royal Jelly on Hepatotoxicity and Oxidative Stress Induced by Molybdenum Nanoparticles and/or Cadmium Chloride in Male Rats

Simple Summary

The aim of the present investigation is valuable due to the importance of possible contaminations and negative effects of these cadmium chloride and molybdenum nanoparticles. The physicochemical properties of molybdenum nanoparticles have been characterized, as well as their ultrastructural organization. A rat experimental model was then employed to assess the liver toxicity of molybdenum nanoparticles, even in combination with CdCl₂. The toxicity of molybdenum nanoparticles and cadmium chloride was estimated via liver damage by means of chemico-biological markers of liver injury, serum lipids, inflammation, oxidative status, and histological and immunohistochemistry patterns. Moreover, the possible effects of royal jelly were evaluated. The results clarified that both chemicals induced hepatic toxicity with the excessive triggering of reactive oxygen species that induced severe oxidative injury, histological alterations in the hepatic structure, and hepatic ultrastructure. These results are concurrent with obtaining normal biochemical levels in groups either treated with royal jelly or even a combination of royal jelly and two xenobiotics. The royal jelly is considered an essential potential source of natural antioxidants capable of frustrating the effects of oxidative injury, which is considered the main cause of many diseases.

Abstract

The present study aimed to investigate the effect of the royal jelly (RJ) on hepatotoxicity induced by molybdenum nanoparticles (MoO₃-NPs), cadmium chloride (CdCl₂), or their combination in male rats at biochemical, inflammation, immune response, histological, and ultrastructural levels. The physicochemical properties of MoO₃-NPs have been characterized, as well as their ultrastructural organization. A rat experimental model was employed to assess the liver toxicity of MoO₃-NPs, even in combination with CdCl₂. Different cellular studies indicate divergent mechanisms, from increased reactive oxygen species production to antioxidative damage and cytoprotective activity. Seventy male rats were allocated to groups: (i) control; (ii) MoO₃-NPs (500 mg/kg); (iii) CdCl₂ (6.5 mg/kg); (iv) RJ (85 mg/kg diluted in saline); (v) MoO₃-NPs followed by RJ (30 min after the MoO₃-NPs dose); (vi) CdCl₂ followed by RJ; and (vii) a combination of MoO₃-NPs and CdCl₂, followed by RJ, for a total of 30 successive days. Hepatic functions, lipid profile, inflammation marker (CRP), antioxidant biomarkers (SOD, CAT, GPx, and MDA), and genotoxicity were examined. Histological changes, an immunological marker for caspase-3, and transmission electron microscope variations in the liver were also investigated to indicate liver status. The results showed that RJ alleviated the hepatotoxicity of MoO₃-NPs and/or CdCl₂ by improving all hepatic vitality markers. In conclusion, the RJ was more potent and effective as an antioxidant over the oxidative damage induced by the combination of MoO₃-NPs and CdCl₂.

Causation of Oxidative Stress and Defense Response of a Yeast Cell Model after Treatment with Orthodontic Alloys Consisting of Metal Ions

Misaligned teeth have a tremendous impact on oral and dental health, and the most efficient method of correcting the problem is orthodontic treatment with orthodontic appliances. The study was conducted to investigate the metal composition of selected orthodontic alloys, the release of metal ions, and the oxidative consequences that the metal ions may cause in the cell. Different sets of archwires, stainless steel brackets, and molar bands were incubated in artificial saliva for 90 days. The composition of each orthodontic material and quantification of the concentration of metal ions released were evaluated. Metal ion mixtures were prepared to determine the occurrence of oxidative stress, antioxidant enzyme defense system, and oxidative damage to proteins. The beta titanium alloy released the fewest metal ions and did not cause oxidative stress or protein damage. The metal ions from stainless steel and the cobalt-chromium alloy can cause oxidative stress and protein damage only at high concentrations. All metal ions from orthodontic alloys alter the activity of antioxidant enzymes in some way. The determined amounts of metal ions released from orthodontic appliances in a simulated oral environment are still below the maximum tolerated dose, and the concentrations of released metal ions are not capable of inducing oxidative stress, although some changes in antioxidant enzyme activity were observed at these concentrations.

Novel fabrication of dual nanoparticle loaded-co-polymeric dressing for effective healing efficiency in wound care after fracture surgery

In the present study, curcumin loaded chitosan/poly ethylene glycol nanomaterial (CUR loaded CH/PEG/AgNPs) was fabricated and characterized for wound healing efficiency after fracture surgery. The interaction of functional groups and crystal nature were recorded under FTIR and XRD spectrometer and reveals that the stabilization and purity of NPs was mediated by OH/NH₂ groups in chitosan. FESEM showed the presence of spherical and well dispersed particles. The average size of the particle was 13.48 nm. The CUR loaded CH/PEG/AgNPs showed higher swelling capacity (495.6 g/g) in phosphate buffer saline compared to water (140.2 g/g). The drug loading efficiency was higher in CUR loaded CH/PEG/AgNPs compared to CH/PEG films as recorded by the absorbance peak at 460 nm corresponds to curcumin in the composite. A dose dependent cytotoxicity of CUR loaded CH/PEG/AgNPs was noticed on Vero cells. The viability of Vero cells was increased to 96.5% at 100 μg/mL. A remarkable change in Vero cells such as condensed nuclei and membrane blabbing was noticed in cells treated with CUR loaded CH/PEG/AgNPs. A greater inhibition of Staphylococcus aureus and Escherichia coli was noticed at 24 h and 48 h treated with CUR loaded CH/PEG/AgNPs. A greater healing effect by increasing the wound contraction (98% on day 12) was observed with CUR loaded CH/PEG/AgNPs compared to control. Histopathological examination demonstrated that CUR loaded CH/PEG/AgNPs showed complete tissue regeneration in wound excised rats. The results of this study conclude that CUR loaded CH/PEG/AgNPs could be promising candidate to prevent microbial infections in wound, healing wound rapidly and inhibit the proliferation of apoptotic cells. Thus, CUR loaded CH/PEG/AgNPs could be a potential therapeutic agent with broad spectrum applications in the future. HighlightsA new approach was used to develop curcumin-loaded chitosan/poly(ethylene glycol)/AgNPs.The CUR-loaded CH/PEG/AgNPs were confirmed to be crystals by XRD analysis.The prepared CH/PEG/AgNPs were spherical and averaged 13.48 nm in size.The growth of S. aureus and E. coli were inhibited mostly by CH/PEG/AgNPs treatment.CUR loaded CH/PEG/AgNPs showed complete tissue regeneration in wound excised mice.

Effects of polycyclic aromatic hydrocarbons and multiple metals co-exposure on the mosaic loss of chromosome Y in peripheral blood

Mosaic loss of chromosome Y (mLOY) is an indicator of genome instability, but the environmental stressors of mLOY remained largely unknown. In this study, we detected the internal exposure levels of 11 polycyclic aromatic hydrocarbon (PAH) metabolites and 22 metals among 888 coke-oven workers, and calculated their blood mLOY based on genome-wide SNP genotyping data and presented as median log R ratio (mLRR-Y). The generalized linear model (GLM), LASSO, and Bayesian kernel machine regression (BKMR), were used to select mLOY-relevant chemicals. The results of these models consistently suggested the negative dose-response relationships of urinary 1-hydroxynaphthalene (1-OHNa), antimony (Sb), and molybdenum (Mo) with mLRR-Y. There were no pairwise interactions between these three chemicals (P_interaction > 0.05), but subjects with high exposure to ≥ 2 kinds of these chemicals showed reducing mLRR-Y [β(95%CI) = - 0.015(- 0.023, - 0.008)], increasing oxidative DNA damage (marked by 8-hydroxydeoxyguanosine) [β(95%CI) = 0.625(0.454, 0.796)] and chromosome damage (marked by micronucleus frequency in lymphocytes) [frequency ratio (FR) and 95%CI = 1.146(1.047, 1.225)] than those with low exposure to all these chemicals. The combined effects of 1-OHNa, Sb, and Mo on elevating DNA damage may partly explain their joint effects on increased blood mLOY. These results provided a new insight into environmental hazards co-exposure on chromosome-Y deletions.

Nanotheranostics for the Management of Hepatic Ischemia-Reperfusion Injury

Hepatic ischemia-reperfusion injury (IRI), in which an insufficient oxygen supply followed by reperfusion leads to an inflammatory network and oxidative stress in disease tissue to cause cell death, always occurs after liver transplantations and sections. Although pharmacological treatments favorably prevent or protect the liver against experimental IRI, there have been few successes in clinical applications for patient benefits because of the incomprehension of complicated IRI-induced signaling events as well as short blood circulation time, poor solubility, and severe side reactions of most antioxidants and anti-inflammatory drugs. Nanomaterials can achieve targeted delivery and controllable release of contrast agents and therapeutic drugs in desired hepatic IRI regions for enhanced imaging sensitivity and improved therapeutic effects, emerging as novel alternative approaches for hepatic IRI diagnosis and therapy. In this review, the application of nanotechnology is summarized in the management of hepatic IRI, including nanomaterial-assisted hepatic IRI diagnosis, nanoparticulate systems-mediated remission of reactive oxygen species-induced tissue injury, and nanoparticle-based targeted drug delivery systems for the alleviation of IRI-related inflammation. The current challenges and future perspectives of these nanoenabled strategies for hepatic IRI treatment are also discussed.

Effect of Ag nanoparticles on viability of MCF-7 and Vero cell lines and gene expression of apoptotic genes

Background

The newly emerged technology, nanotechnology, represents a promising solution for many medical and industrial problems. Random targeting, resistance, and side effects are the main disadvantages of the available cancer chemotherapy which are critical aspects needed to be managed. So the aim of the study was to suggest the nanoparticles as an alternative therapy for the available therapies through detecting the cytotoxic effect of Ag nanoparticles against cancer and normal cell lines and how they affect the apoptotic function and the genes involved.

Results

Ag NPs exhibited a killing rate of 40% in MCF-7 cells (the cancer cell model) at a concentration of 100 μg/ml with almost no effect on Vero cells (the normal cell model). Concerning the phenotypic apoptotic changes that were analyzed by Acridine orange and eosin and hematoxylin, Ag NPs caused the apoptosis and Vacuole degeneration as well as cell formation and the emergence of Necrotic cells in MCF-7 cells, whereas in the normal cell line Vero, no change appears in its phenotype.

Treating MCF-7 and Vero cells with Ag NPs upregulated the P53 and P21 gene expression in Vero cells, but their expression was downregulated in MCF-7 cells. PTEN was augmented in both MCF-7 and Vero cells compared to the control.

Conclusions

The AgNPs displayed selective effect in their cytotoxicity and both induced the apoptosis effect and might be suggested as a potential therapy since an increase in PTEN expression (up to 250-fold more compared to the control) due to the treatment with AgNPs augments the tumor suppressor effects of the PTEN.

Inhibition of ROS/NLRP3/Caspase-1 mediated pyroptosis alleviates excess molybdenum-induced apoptosis in duck renal tubular epithelial cells

OBJECTIVE

Excess molybdenum (Mo) is harmful to the body, and the kidney is the vital target organ for Mo exposure. This study focused on the impacts of excess Mo on pyroptosis and the relationship between pyroptosis and apoptosis in kidney.

METHODS

The duck renal tubular epithelial cells were treated with (NH₄)₆Mo₇O₂₄·4H₂O (0, 480, 720 and 960 μM Mo), N-acetyl-L-cysteine (NAC) (100 μM), Z-YVAD-fluoromethylketone (YVAD) (10 μM) and the combination of Mo and NAC or YVAD for 12 h. The LDH release and IL-1β, IL-18 contents of cell supernatant were detected by LDH and ELISA kits. The MMP and ROS level were measured using MMP and ROS kits by flow cytometry. The apoptotic rate of cell was detected by AO/EB counterstaining. Pyroptosis and apoptosis-related factors mRNA and protein levels were assayed by real-time qPCR and western blot, respectively.

RESULTS

Excessive Mo markedly increased LDH, IL-18, IL-1β releases and induced overproduction of ROS, pyroptosis-related factors mRNA and protein levels. NAC and YVAD dramatically decreased pyroptosis induced by Mo. Simultaneously, YVAD significantly changed apoptosis-related factors mRNA and protein levels, and reduced cell apoptotic rate.

CONCLUSION

Excessive Mo exposure can induce pyroptosis by the ROS/NLRP3/Caspase-1 pathway in duck renal tubular epithelial cells, and restraining pyroptosis of Caspase-1 dependence might weaken excess Mo-induced apoptosis. The study provides theoretical basis for excess Mo exposure nephrotoxic researches on waterfowl and the interplay between pyroptosis and apoptosis highlights a new sight into the mechanism of Mo-induced nephrotoxicity.

Molybdenum-based hetero-nanocomposites for cancer therapy, diagnosis and biosensing application: Current advancement and future breakthroughs

In recent years, there have been significant advancements in the nanotechnology for cancer therapy. Even though molybdenum disulphide (MoS2)-based nanocomposites demonstrated extensive applications in biosensing, bioimaging, phototherapy, the review article focusing on MoS2 nanocomposite platform has not been accounted for yet. The review summarizes recent strategies on design and fabrication of MoS2-based nanocomposites and their modulated properties in cancer treatment. The review also discussed several therapeutic strategies (photothermal, photodynamic, immunotherapy, gene therapy and chemotherapy) and their combinations for efficient cancer therapy along with certain case studies. The review also inculcates various diagnostic techniques viz. magnetic resonance imaging, computed tomography, photoacoustic imaging and fluorescence imaging for diagnosis of cancer.

Assessment of acute toxicological effects of molybdenum(IV) disulfide nano- and microparticles after single intratracheal administration in rats

Despite growing applications of molybdenum(IV) sulfide (MoS₂) nano- and microparticles in their capacity as lubricants, data available on their safety are scarce. In this study the effect of MoS₂ nano- and microparticles after single intratracheal instillation in rats has been analyzed. MoS₂ suspensions were administered at the dose of 1.5 or 5 mg MoS₂/kg body weight. The analysis after 24 h and 7 days included: blood biochemical parameters, hematological parameters, bronchoalveolar lavage fluid (BALF) parameters with selected cytokines, a comet assay and histopathological examination. In the BALF cells isolated from animals exposed to both forms, numerous macrophages loaded with particles were observed. The hematological and biochemical parameters analyzed 24 h or 7 days after the exposure to both forms did not show any biologically meaningful changes. Comet assay results showed no genotoxic effect. The histopathological analysis of the lungs revealed inflammatory changes in the respiratory system of the treated animals, slightly stronger for the microsized form. The deposits of particles observed in the lung tissue up to 7 days after the instillation indicate their easy penetration through the epithelium and prolonged clearance. Concluding, no meaningful acute systemic effects were observed, however some pathological changes were noted in the lung tissue.

Are Metal Ions That Make up Orthodontic Alloys Cytotoxic, and Do They Induce Oxidative Stress in a Yeast Cell Model?

Compositions of stainless steel, nickel-titanium, cobalt-chromium and β-titanium orthodontic alloys were simulated with mixtures of Fe, Ni, Cr, Co, Ti and Mo metal ions as potential oxidative stress-triggering agents. Wild-type yeast Saccharomyces cerevisiae and two mutants ΔSod1 and ΔCtt1 were used as model organisms to assess the cytotoxicity and oxidative stress occurrence. Metal mixtures at concentrations of 1, 10, 100 and 1000 µM were prepared out of metal chlorides and used to treat yeast cells for 24 h. Every simulated orthodontic alloy at 1000 µM was cytotoxic, and, in the case of cobalt-chromium alloy, even 100 µM was cytotoxic. Reactive oxygen species and oxidative damage were detected for stainless steel and both cobalt-chromium alloys at 1000 µM in wild-type yeast and 100 µM in the ΔSod1 and ΔCtt1 mutants. Simulated nickel-titanium and β-titanium alloy did not induce oxidative stress in any of the tested strains.

Titanium Alloy Intramedullary Nails and Plates Affect Serum Metal Ion Levels within the Fracture Healing Period

Titanium alloy implants are the most used materials for the fixation of lower extremity fractures. Although these implants were thought to be inert materials in vitro, several studies have shown increased serum and remote tissue metal ion levels due to wear of implants and friction of the bone-implant interface in vivo. The aim of this study was to investigate the alteration of serum metal ion levels that are released from intramedullary nails and plates used for the fixation of lower extremity fractures, within the fracture healing period. The study included 20 adult patients, who were treated with intramedullary nail or plate osteosynthesis due to closed lower extremity fractures. Alterations of serum titanium, aluminum, molybdenum, and vanadium levels were evaluated at 6, 12, 18, and 24 weeks postoperatively. A statistically significant increase was determined in serum titanium, aluminum, molybdenum, and vanadium ion levels in the intramedullary nail and plate groups at the end of the follow-up period. Pairwise comparisons of metal ion levels between implant groups revealed no significant difference during a 24-week follow-up period. Compared to the control group, statistically significant increased levels of serum titanium, aluminum, vanadium, and molybdenum ions were determined in the implant groups used for the fixation of lower extremity fractures at the end of 24 weeks. In the current literature, the potential toxic effects of prolonged exposure to low levels of these metal ions are still unknown. It can be predicted that long-term metal ion exposure could result in vivo pathological processes in the future.

Induction of fetal abnormalities and genotoxicity by molybdenum nanoparticles in pregnant female mice and fetuses

Increasing the uses of molybdenum (Mo) nanoparticles in a wide range of applications including food, industry, and medicine, resulted in increased human exposure and necessitated the study of their toxic effects. However, almost no studies are available on their genotoxic effects, especially on pregnant females and their fetuses. Therefore, this study was undertaken to estimate the possible induction of genotoxicity and fetal abnormalities, especially fetal malformations and skeletal abnormalities by Mo nanoparticle administration in mice. Oral administration of Mo nanoparticles resulted in significant decreases in the maternal body weight, the number and length of fetuses as well as skeletal abnormalities mainly less ossification and less chondrification. Administration of Mo nanoparticles also caused DNA damage induction which elevated the expression levels of p53, the vital gene in maintaining the genomic stability and cell differentiation in both maternal and fetus tissues. Similarly, the expression levels of E-Cad and N-Cad genes that control skeleton development have also been increased in the tissues of female mice administered Mo nanoparticles and their fetuses. Thus, we concluded that oral administration of Mo nanoparticles induced genotoxic effects and fetal abnormalities that necessitated further studies on the possible toxic effects of Mo nanoparticles.

Preparation, structural, microstructural, mechanical, and cytotoxic characterization of Ti-15Nb alloy for biomedical applications

Titanium alloys are widely used in the biomedical field due to their excellent resistance to corrosion, high mechanical strength/density ratio, low elastic modulus, and good biocompatibility. Niobium is a β-stabilizer element that has the potential to decrease elastic modulus and possesses excellent corrosion resistance. In this article, Ti-15Nb alloy was prepared via arc-melting, with the aim of using it in biomedical applications to replace implants that fail due to mechanical incompatibility with human bone. This Ti-15Nb alloy was structurally, chemically, and microstructurally characterized. Its mechanical properties were analyzed via Vickers microhardness and elastic modulus measurements. The cytotoxicity of the alloy was evaluated via direct and indirect MTT tests. In the direct MTT test, the cells were grown on alloy and in the indirect test, Ti-15Nb alloy extracts were prepared (1 g/1 mL at 310 K for 48 hours). The results of chemical composition showed that the alloy produced has good quality and low content of gaseous impurities, such as oxygen and nitrogen. The obtained results for structure and microstructure indicated the presence of the martensite α' phase. The microhardness of the Ti-15Nb alloy is superior to that of cp-Ti due to solid solution hardening, and the alloy has a better elastic modulus as compared to pure titanium. Cytotoxic effects were not observed. The Ti-15Nb alloy shows good results of mechanical properties and does not show cytotoxic effects. In addition, morphological variations were not found in the cells and good cell adhesion in all the studied conditions was observed. In general, the alloy proposed in this article has satisfactory characteristics as a biomedical material.

Cell cycle and transmembrane mitochondrial potential analysis after treatment with chromium(iii), iron(iii), molybdenum(iii) or nickel(ii) and their mixtures

The aim of this study was to examine the effect of chromium(iii), iron(iii), molybdenum(iii) and nickel(ii) and their combinations on the cell cycle and mitochondrial transmembrane potential (MTP) in BALB/3T3 and HepG2 cells. A statistically significant dose related decrease of the percentage of cells in the G0/G1 and S phases was observed. However, a statistically significant dose related increase of the percentage of cells in the G2/M phase after exposure to chromium(iii), nickel(ii) or molybdenum(iii) at 200-1000 μM concentrations in both cell lines was observed. Moreover, an increase of the percentage of cells in the subG1 phase was observed. In both cell lines a statistically significant dose related decrease of the percentage of cells in the G2/M phase after exposure to iron(iii) at 200-1000 μM concentrations was observed. However, a statistically significant dose related increase of the percentage of cells in the G0/G1 phase after exposure to iron(iii) at 200-1000 μM concentrations was observed. A concentration dependent statistically significant decrease in the level of the MTP was observed in both cell lines after exposure to chromium(iii), iron(iii), nickel(ii) and molybdenum(iii). The results obtained from both cell lines show that HepG2 cells are more sensitive when compared to BALB/3T3 cells. Additions of Cr(iii) at 200 μM plus Fe(iii) at 1000 μM showed a synergistic effect on the cell cycle and MTP. In the case of Cr(iii) at 200 μM plus Mo(iii) at 1000 μM, an antagonistic effect was observed in both analyses. In the case of Cr(iii) at 1000 μM plus Mo(iii), Ni(ii) and Fe(iii) at 200 μM, no changes in the percentage of cells in all phases were observed in both cell lines in both analyses.

Physical, chemical, and toxicological characteristics of particulate emissions from current technology gasoline direct injection vehicles

We assessed the physical, chemical and toxicological characteristics of particulate emissions from four light-duty gasoline direct injection vehicles when operated over the LA92 driving cycle. Our results showed that particle mass and number emissions increased markedly during accelerations. For three of the four vehicles tested, particulate matter (PM) mass and particle number emissions were markedly higher during cold-start and the first few accelerations following the cold-start period than during the hot running and hot-start segments of the LA92 cycle. For one vehicle (which had the highest emissions overall) the hot-start and cold-start PM emissions were similar. Black carbon emissions were also much higher during the cold-start conditions, indicating severe fuel wetting leading to slow evaporation and pool burning, and subsequent soot formation. Particle number concentrations and black carbon emissions showed large reductions during the urban and hot-start phases of the test cycle. The oxidative potential of PM was quantified with both a chemical and a biological assay, and the gene expression impacts of the PM in a macrophage model with PCR (polymerase chain reaction) and ELISA (enzyme-linked immunosorbent assay) analyses. Inter- and intra-vehicle variability in oxidative potential per milligram of PM emitted was relatively low for both oxidative assays, suggesting that real-world emissions and exposure can be estimated with distance-normalized emission factors. The PCR response from signaling markers for oxidative stress (e.g., NOX1) was greater than from inflammatory, AhR (aryl hydrocarbon receptor), or MAPK (mitogen-activated protein kinase) signaling. Protein production associated with inflammation (tumor necrosis factor alpha-TNFα) and oxidative stress (HMOX-1) were quantified and displayed relatively high inter-vehicle variability, suggesting that these pathways may be activated by different PM components. Correlation of trace metal concentrations and oxidative potential suggests a role for small, insoluble particles in inducing oxidative stress.

Single-Chain Atomic Crystals as Extracellular Matrix-Mimicking Material with Exceptional Biocompatibility and Bioactivity

In this study, Mo₃Se₃^- single-chain atomic crystals (SCACs) with atomically small chain diameters of ∼0.6 nm, large surface areas, and mechanical flexibility were synthesized and investigated as an extracellular matrix (ECM)-mimicking scaffold material for tissue engineering applications. The proliferation of L-929 and MC3T3-E1 cell lines increased up to 268.4 ± 24.4% and 396.2 ± 8.1%, respectively, after 48 h of culturing with Mo₃Se₃^- SCACs. More importantly, this extremely high proliferation was observed when the cells were treated with 200 μg mL^-1 of Mo₃Se₃^- SCACs, which is above the cytotoxic concentration of most nanomaterials reported earlier. An ECM-mimicking scaffold film prepared by coating Mo₃Se₃^- SCACs on a glass substrate enabled the cells to adhere to the surface in a highly stretched manner at the initial stage of cell adhesion. Most cells cultured on the ECM-mimicking scaffold film remained alive; in contrast, a substantial number of cells cultured on glass substrates without the Mo₃Se₃^- SCAC coating did not survive. This work not only proves the exceptional biocompatible and bioactive characteristics of the Mo₃Se₃^- SCACs but also suggests that, as an ECM-mimicking scaffold material, Mo₃Se₃^- SCACs can overcome several critical limitations of most other nanomaterials.

Cytotoxicity of Iron (III), Molybdenum (III), and their Mixtures in BALB/3T3 and HepG2 Cells

INTRODUCTION

Iron and molybdenum are essential trace elements for cell metabolism. They are involved in maintaining proper functions of enzymes, cell proliferation, and metabolism of DNA.

MATERIAL AND METHODS

BALB/3T3 and HepG2 cells were incubated with iron chloride or molybdenum trioxide at concentrations from 100 to 1,400 μM. The cells were also incubated in mixtures of iron chloride at 200 μM plus molybdenum trioxide at 1,000 μM or iron chloride at 1,000 μM plus molybdenum trioxide at 200 μM. Cell viability was determined with MTT reduction, LHD release, and NRU tests.

RESULTS

A decrease in cell viability was observed after incubating both cell lines with iron chloride or molybdenum trioxide. In cells incubated with mixtures of these trace elements, a decrease in cell viability was observed, assessed by all the used assays.

CONCLUSION

Iron (III) and molybdenum (III) decrease cell viability in normal and cancer cells. A synergistic effect of the mixture of these elements was observed.

Anticancer Potential of Green Synthesized Silver Nanoparticles Using Extract of Nepeta deflersiana against Human Cervical Cancer Cells (HeLA)

In this study, silver nanoparticles (AgNPs) were synthesized using aqueous extract of Nepeta deflersiana plant. The prepared AgNPs (ND-AgNPs) were examined by ultraviolet-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDX). The results obtained from various characterizations revealed that average size of synthesized AgNPs was 33 nm and in face-centered-cubic structure. The anticancer potential of ND-AgNPs was investigated against human cervical cancer cells (HeLa). The cytotoxic response was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), neutral red uptake (NRU) assays, and morphological changes. Further, the influence of cytotoxic concentrations of ND-AgNPs on oxidative stress markers, reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP), cell cycle arrest and apoptosis/necrosis was studied. The cytotoxic response observed was in a concentration-dependent manner. Furthermore, the results also showed a significant increase in ROS and lipid peroxidation (LPO), along with a decrease in MMP and glutathione (GSH) levels. The cell cycle analysis and apoptosis/necrosis assay data exhibited ND-AgNPs-induced SubG1 arrest and apoptotic/necrotic cell death. The biosynthesized AgNPs-induced cell death in HeLA cells suggested the anticancer potential of ND-AgNPs. Therefore, they may be used to treat the cervical cancer cells.

Pro- and antioxidant activity of chromium(III), iron(III), molybdenum(III) or nickel(II) and their mixtures

The aim of this study was to examine the effect of chromium(III), iron(III), molybdenum(III) and nickel(II) and their combinations on pro- and antioxidant activity in mouse embryo fibroblasts and liver cancer cells. The present study shows that chromium(III), iron(III), nickel(II) and molybdenum(III) induce oxidative stress. In the case of chromium(III), nickel(II) and molybdenum(III) the intracellular ROS were dominant. However, in the case of iron(III) MDA was dominant - the end product of lipid peroxidation. Antioxidant activity of superoxide dismutase and catalase increased in low concentration of chromium(III); however, they decreased in higher concentrations. The same enzymes decreased after iron(III), nickel(II) and molybdenum(III) treatment in dose dependent manner. The activity of glutathione peroxidise decreased in dose dependent manner in all used microelements. Additions of Cr(III) at 200 μM plus Fe(III) at 1000 μM showed synergistic effect in ROS production and in lowering antioxidant activity. The same type of interaction in pairs Cr(III) at 1000 μM plus Fe(III) or Ni(II) or Mo(III) at concentration of 200 μM was observed. The protective effects of Cr(III) in antioxidant activity and in lowering intracellular ROS production in pairs of Cr(III) at 200 μM and Ni(II) or Mo(III) at concentration of 1000 μM were observed.

Cationic Substitutions in Hydroxyapatite: Current Status of the Derived Biofunctional Effects and Their In Vitro Interrogation Methods

High-performance bioceramics are required for preventing failure and prolonging the life-time of bone grafting scaffolds and osseous implants. The proper identification and development of materials with extended functionalities addressing socio-economic needs and health problems constitute important and critical steps at the heart of clinical research. Recent findings in the realm of ion-substituted hydroxyapatite (HA) could pave the road towards significant developments in biomedicine, with an emphasis on a new generation of orthopaedic and dentistry applications, since such bioceramics are able to mimic the structural, compositional and mechanical properties of the bone mineral phase. In fact, the fascinating ability of the HA crystalline lattice to allow for the substitution of calcium ions with a plethora of cationic species has been widely explored in the recent period, with consequent modifications of its physical and chemical features, as well as its functional mechanical and in vitro and in vivo biological performance. A comprehensive inventory of the progresses achieved so far is both opportune and of paramount importance, in order to not only gather and summarize information, but to also allow fellow researchers to compare with ease and filter the best solutions for the cation substitution of HA-based materials and enable the development of multi-functional biomedical designs. The review surveys preparation and synthesis methods, pinpoints all the explored cation dopants, and discloses the full application range of substituted HA. Special attention is dedicated to the antimicrobial efficiency spectrum and cytotoxic trade-off concentration values for various cell lines, highlighting new prophylactic routes for the prevention of implant failure. Importantly, the current in vitro biological tests (widely employed to unveil the biological performance of HA-based materials), and their ability to mimic the in vivo biological interactions, are also critically assessed. Future perspectives are discussed, and a series of recommendations are underlined.

Evaluation of immunoresponses and cytotoxicity from skin exposure to metallic nanoparticles

Nanotechnology is an interdisciplinary science that has developed rapidly in recent years. Metallic nanoparticles (NPs) are increasingly utilized in dermatology and cosmetology, because of their unique properties. However, skin exposure to NPs raises concerns regarding their transdermal toxicity. The tight junctions of epithelial cells form the skin barrier, which protects the host against external substances. Recent studies have found that NPs can pass through the skin barrier into deeper layers, indicating that skin exposure is a means for NPs to enter the body. The distribution and interaction of NPs with skin cells may cause toxic side effects. In this review, possible penetration pathways and related toxicity mechanisms are discussed. The limitations of current experimental methods on the penetration and toxic effects of metallic NPs are also described. This review contributes to a better understanding of the risks of topically applied metallic NPs and provides a foundation for future studies.

Alterations in antioxidant function and cell apoptosis in duck spleen exposed to molybdenum and/or cadmium

To investigate the effects of molybdenum (Mo) and/or cadmium (Cd) on antioxidant function and the apoptosis-related genes in duck spleens. Sixty healthy 11-day-old ducks were randomly divided into six groups of 10 ducks (control, low Mo group, high Mo, Cd, low Mo + Cd, and high Mo + Cd groups). All were fed a basal diet containing low or high dietary doses of Mo and/or Cd. Relative spleen weight, antioxidant indices, apoptosis-related gene mRNA expression levels, and ultrastructural changes were evaluated after 120 days. The results showed that the relative spleen weight decreased significantly in the high Mo + Cd treatment group which compared with control group. Malondialdehyde levels increased and xanthine oxidase and catalase activities decreased in the Mo and/or Cd groups compared with levels in the control group. Bak-1 and Caspase-3 expressions were upregulated in the high Mo + Cd group, while Bcl-2 was downregulated. In addition, mitochondrial crest fracture, swelling, vacuolation, deformed nuclei, and karyopyknosis in both Mo + Cd treated groups were more severe than in the other groups. The results suggest that Mo and/or Cd can induce oxidative stress and apoptosis of spleen via effects on the mitochondrial intrinsic pathway. Moreover, the results indicate the two elements have a possible synergistic relationship.

Ag-doping regulates the cytotoxicity of TiO2 nanoparticles via oxidative stress in human cancer cells

We investigated the anticancer potential of Ag-doped (0.5-5%) anatase TiO2 NPs. Characterization study showed that dopant Ag was well-distributed on the surface of host TiO2 NPs. Size (15 nm to 9 nm) and band gap energy (3.32 eV to 3.15 eV) of TiO2 NPs were decreases with increasing the concentration of Ag dopant. Biological studies demonstrated that Ag-doped TiO2 NP-induced cytotoxicity and apoptosis in human liver cancer (HepG2) cells. The toxic intensity of TiO2 NPs was increases with increasing the amount of Ag-doping. The Ag-doped TiO2 NPs further found to provoke reactive oxygen species (ROS) generation and antioxidants depletion. Toxicity induced by Ag-doped TiO2 NPs in HepG2 cells was efficiently abrogated by antioxidant N-acetyl-cysteine (ROS scavenger). We also found that Ag-doped TiO2 NPs induced cytotoxicity and oxidative stress in human lung (A549) and breast (MCF-7) cancer cells. Interestingly, Ag-doped TiO2 NPs did not cause much toxicity to normal cells such as primary rat hepatocytes and human lung fibroblasts. Overall, we found that Ag-doped TiO2 NPs have potential to selectively kill cancer cells while sparing normal cells. This study warranted further research on anticancer potential of Ag-doped TiO2 NPs in various types of cancer cells and in vivo models.

Effect of Molybdenum Nanoparticles on Blood Cells, Liver Enzymes, and Sexual Hormones in Male Rats

Despite an increasing surge in application of nanoparticles in industries, there is a serious lack of information concerning their impact on human health and the environment. The present study investigated effects of molybdenum nanoparticles (Mo NPs) injected intraperitoneally into Sprague-Dawley rats at different doses of Mo NPs (5, 10, and 15 mg/kg BW per day) during a period of 28 days. Hematological and biochemical parameters as well as sexual hormones and histopathological examinations of the liver and testis were assessed and compared with control group. The results showed that the serum levels of testosterone decreased significantly in both groups of 10 and 15 mg (Mo NPs)/kg BW in comparison with the control group (p < 0.05). However, there were insignificant differences observed in luteinizing hormone (LH) levels and hematological parameters when compared with the control group (p > 0.05). The results of liver enzymes showed that serum levels of aspartate aminotransferase (AST) decreased significantly in both dosage groups of 5 and 10 mg/kg BW (Mo NPs) when compared with the control group (p < 0.05), and significant decrease obtained in lactate dehydrogenase (LDH) levels at dose of 5 mg/kg BW in comparison with the control group (p < 0.05). The histopathological examination of testis showed a decrease in number of Leydig cells. Also, the number of chronic inflammatory cells increased in portal triad and parenchyma in liver tissue of rats exposed to Mo NPs.

Biocompatibility and degradation of gold-covered magneto-elastic biosensors exposed to cell culture

Magneto-elastic materials (ME) have important advantages when applied as biosensors due to the possibility of wireless monitoring. Commercial Metglas 2826MB3™ (FeNiMoB) is widely used, however sensor stabilization is an important factor for biosensor performance. This study compared the effects of biocompatibility and degradation of the Metglas 2826MB3™ alloy, covered or not with a gold layer, when in contact with cell culture medium. Strips of amorphous Metglas 2826MB3™ were cut and coated with thin layers of Cr and Au, as verified by Rutherford Backscattering Spectroscopy (RBS). Using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), the presence of metals in the culture medium was quantitatively determined for up to seven days after alloy exposure. Biocompatibility of fibroblast Chinese Hamster Ovary (CHO) cultures was tested and cytotoxicity parameters were investigated by indirect means of reduction of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) at 1, 2 and 7 days. Cell death was further evaluated through in situ analysis using Acridine Orange/Ethidium Bromide (AO/EB) staining and images were processed with ImageJ software. Ions from Metglas(®) 2826MB3™ induced a degradation process in living organisms. The cytotoxicity assay showed a decrease in the percentage of live cells compared to control for the ME strip not coated with gold. AO/EB in situ staining revealed that most of the cells grown on top of the gold-covered sensor presented a normal morphology (85.46%). Covering ME sensors with a gold coating improved their effectiveness by generating protection of the transducer by reducing the release of ions and promoting a significant cell survival.

Verbesina encelioides: cytotoxicity, cell cycle arrest, and oxidative DNA damage in human liver cancer (HepG2) cell line

BACKGROUND

Cancer is a major health problem and exploiting natural products have been one of the most successful methods to combat this disease. Verbesina encelioides is a notorious weed with various pharmacological properties. The aim of the present investigation was to screen the anticancer potential of V. encelioides extract against human lung cancer (A-549), breast cancer (MCF-7), and liver cancer (HepG2) cell lines.

METHODS

A-549, MCF-7, and HepG2 cells were exposed to various concentrations of (10-1000 μg/ml) of V. encelioides for 24 h. Further, cytotoxic concentrations (250, 500, and 1000 μg/ml) of V. encelioides induced oxidative stress (GSH and LPO), reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP), cell cycle arrest, and DNA damage in HepG2 cells were studied.

RESULTS

The exposure of cells to 10-1000 μg/ml of extract for 24 h, revealed the concentrations 250-1000 μg/ml was cytotoxic against MCF-7 and HepG2 cells, but not against A-549 cells. Moreover, the extract showed higher decrease in the cell viability against HepG2 cells than MCF-7 cells. Therefore, HepG2 cells were selected for further studies viz. oxidative stress (GSH and LPO), reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP), cell cycle arrest, and DNA damage. The results revealed differential anticancer activity of V. encelioides against A-549, MCF-7 and HepG2 cells. A significant induction of oxidative stress, ROS generation, and MMP levels was observed in HepG2 cells. The cell cycle analysis and comet assay showed that V. encelioides significantly induced G2/M arrests and DNA damage.

CONCLUSION

These results indicate that V. encelioides possess substantial cytotoxic potential and may warrant further investigation to develop potential anticancer agent.

The Co-induced Effects of Molybdenum and Cadmium on Antioxidants and Heat Shock Proteins in Duck Kidneys

Molybdenum (Mo) is an essential element for human beings and animals; however, high dietary intake of Mo can lead to adverse reactions. Cadmium (Cd) is harmful to health. To investigate the toxicity of Mo combined with Cd in duck kidneys, 240 ducks were randomly divided into six groups and treated with a commercial diet containing Mo, Cd or Mo combined with Cd. Kidneys were collected on days 30, 60, 90 and 120 for determining the expression of heat shock proteins (HSPs), including HSP60, HSP70 and HSP90 in the kidney through quantitative RT-PCR. We also determined the antioxidant activity indexes in the kidney mitochondria. Moreover, kidney tissues at 120 days were subjected to histopathological analysis with the optical microscope. The results indicated that the expression of HSPs was highly significantly (P < 0.01) upregulated in the kidneys of the combination groups and the Cd group. Exposure to Cd and a high dose of Mo decreased the total antioxidative capacity and the activity of xanthine oxidase, while malondialdehyde levels and the activity of nitric oxide synthase increased compared with those of the control groups in the kidney mitochondria. This was particularly evident at 90 and 120 days. Histopathological lesions included congestion and bleeding in the renal interstitium, swelling of the distal convoluted tubule epithelial cells, granular degeneration and blister degeneration in the renal tubular epithelial cells. These results suggest that a combination of Mo and Cd leads to greater tissue damage and has a synergistic effect on kidney damage. Oxidative damage of kidney mitochondria may be a potential nephrotoxicity mechanism of molybdenum and cadmium, and the high expression of HSPs may play a role in the resistance of kidney toxicity induced by Mo and Cd.

Threshold Dose of Three Types of Quantum Dots (QDs) Induces Oxidative Stress Triggers DNA Damage and Apoptosis in Mouse Fibroblast L929 Cells

Although it has been reported that fluorescent quantum dots (QDs) have obvious acute toxic effects in vitro, their toxic effects at low doses or threshold doses are still unknown. Therefore, we evaluated the biological histocompatibility and in vitro toxicity of three types of QDs at threshold doses. Also, we compared the toxic effects of QDs with different raw chemical compositions and sizes. The results showed that low concentrations of QDs (≤7 μg/mL) had no obvious effect on cell viability and cell membrane damage, oxidative damage, cell apoptosis or DNA damage. However, QD exposure led to a significant cytotoxicity at higher doses (≥14 μg/mL) and induced abnormal cellular morphology. In addition, when comparing the three types of QDs, 2.2 nm CdTe QDs exposure showed a significantly increased proportion of apoptotic cells and significant DNA damage, suggesting that size and composition contribute to the toxic effects of QDs. Based on these discussions, it was concluded that the concentration (7 μg/mL) may serve as a threshold level for these three types of QDs only in L929 fibroblasts, whereas high concentrations (above 14 μg/mL) may be toxic, resulting in inhibition of proliferation, induction of apoptosis and DNA damage in L929 fibroblasts.