Mitochondrial protective and antioxidant agents protect toxicity induced by depleted uranium in isolated human lymphocytes

A Mitochondria-Targeted Heptamethine Indocyanine Small Molecular Chelator for Attenuating Uranium Nephrotoxicity

Radionuclide uranium has both a chemical and radioactive toxicity, leading to severe nephrotoxicity as it predominantly deposits itself in the kidneys after entering into human bodies. It crosses renal cell membranes, accumulates in mitochondria and causes mitochondrial oxidative damage and dysfunction. In this study, a mitochondria-targeted heptamethine indocyanine small molecule chelator modified with gallic acid (IR-82) is synthesized for uranium detoxication. Both gallic acid and sulfonic acid, as two hydrophilic endings, make IR-82, being excreted feasibly through kidneys. Gallic acid with polyphenol groups has a steady metal chelation effect and potent antioxidant ability, which may facilitate IR-82-alleviated uranium nephrotoxicity simultaneously by enhancing uranium decorporation from the kidneys and reducing mitochondrial oxidative damage. Cell viability assays demonstrate that IR-82 can significantly improve the cell viability of uranium-exposed human renal (HK-2) cells. It is also demonstrated to accumulate in mitochondria and reduce mitochondrial ROS and total intracellular ROS, as well as intracellular uranium content. In vivo imaging experiments in mice show that IR-82 could be excreted out through kidneys. ICP-MS tests further reveal that IR-82 can efficiently decrease the uranium deposition in mouse kidneys. IR-82 treatment improves the animal survival rate and renal function of experimental mice after high-dose uranium exposure. Collectively, our study may evidence that the development of uranium decorporation agents with kidney-mitochondrion dual targeting abilities is a promising strategy for attenuating uranium-induced nephrotoxicity.

Screening and signifying the uranium remediation level of Alternanthera philoxeroides and Eichhornia crassipes from aquatic medium

Uranium is causing a hazardous impact on the human population throughout the globe. Different methods of remediation have been documented but the approach of phytoremediation has been praised throughout the globe. The bioaccumulation of uranium especially as a hyper-accumulator, has been documented in limited plant species. Therefore the current studies were conducted to elaborate on the overall U accumulation, biochemical and photochemical reactions in Alternanthera philoxeroides and Eichhornia crassipes to different concentrations of Uranium. The results showed that the accumulation of U in A.philoxeroides is higher; followed by E.crassipes; with maximum amounts of roots accumulation. Overall A.philoxeroides and E.crassipes accumulate as much as 948.88 mg/kg and 801.87 mg/kg on a dry weight basis. The biochemical results showed that Superoxide dismutase (SOD) decreased in the leaves and stem of A.philoxeroides; whereas an increase has been seen in E.crassipes in response to all treatments. peroxidase (POD) and Catalase (CAT) showed irregular response to all treatments; where the main increase was observed at T3 (120 μmol/L) and 72 h up to 138 μ/g-FW (POD) and 178 μ/g-FW (CAT) in A.philoxeroides and 1870 μ/g-FW (POD) and 73 μ/g-FW (CAT) in E.crassipes, respectively. The correlation coefficient between the fluorescence ratio Fv/Fm and the concentrations of U-treatment was significantly negative. It is concluded from the results that Uranium halted the biochemical and photochemical reaction but the plants resisted its impact while accumulating a good amount of uranium which is a good prospect for future interventions for the in-situ remediation of uranium-affected sites.

Proteomics analysis of resistance mechanism of Trichoderma harzianum under U(VI) stress

Trichoderma harzianum has a certain resistance to Hexavalent Uranium (U(VI)), but its resistance mechanism is unknown. Based on proteomics sequencing using DIA mode, differentially expressed proteins (DEPs) of Trichoderma harzianum under U(VI) stress were identified. GO enrichment, KEGG annotation analysis and DEPs annotation were performed. The results showed that 8 DEPs, 8 DEPs and 15 DEPs were obtained in the low-dose, medium-dose and high-dose groups, respectively. The functional classification of GO demonstrated that DEPs were associated with 17 molecular functions, 5 biological processes, and 5 cellular components. Furthermore, DEPs were enriched in transport and catabolism, energy metabolism, translation, and signal transduction. These findings showed that Trichoderma harzianum was significantly changed in protein expression and signaling pathway after U(VI) exposure. Therefore, these results have provided Trichoderma harzianum with a theoretical background that can be applied to environmental cleanup.

Gallic acid rescues uranyl acetate induced-hepatic dysfunction in rats by its antioxidant and cytoprotective potentials

BACKGROUND

The liver was identified as a primary target organ for the chemo-radiological effects of uranyl acetate (UA). Although the anti-oxidant and anti-apoptotic properties of gallic acid (GA) make it a promising phytochemical to resist its hazards, there is no available data in this area of research.

METHODS

To address this issue, eighteen rats were randomly and equally divided into three groups. One group was received carboxymethyl cellulose (vehicle of GA) and kept as a control. The UA group was injected intraperitoneally with UA at a single dose of 5 mg/kg body weight. The third group (GA + UA group) was treated with GA orally at a dose of 100 mg/kg body weight for 14 days before UA exposure. UA was injected on the 15th day of the experiment in either the UA group or the GA + UA group. The biochemical, histological, and immunohistochemical findings in the GA + UA group were compared to both control and UA groups.

RESULTS

The results showed that UA exposure led to a range of adverse effects. These included elevated plasma levels of aspartate aminotransferase, lactate dehydrogenase, total protein, globulin, glucose, total cholesterol, triglycerides, low-density lipoprotein cholesterol, and very-low-density lipoprotein and decreased plasma levels of high-density lipoprotein cholesterol. The exposure also disrupted the redox balance, evident through decreased plasma total antioxidant capacity and hepatic nitric oxide, superoxide dismutase, reduced glutathione, glutathione-S-transferase, glutathione reductase, and glutathione peroxidase and increased hepatic oxidized glutathione and malondialdehyde. Plasma levels of albumin and alanine aminotransferase did not significantly change in all groups. Histopathological analysis revealed damage to liver tissue, characterized by deteriorations in tissue structure, excessive collagen accumulation, and depletion of glycogen. Furthermore, UA exposure up-regulated the immuno-expression of cleaved caspase-3 and down-regulated the immuno-expression of nuclear factor-erythroid-2-related factor 2 in hepatic tissues, indicating an induction of apoptosis and oxidative stress response. However, the pre-treatment with GA proved to be effective in mitigating these negative effects induced by UA exposure, except for the disturbances in the lipid profile.

CONCLUSIONS

The study suggests that GA has the potential to act as a protective agent against the adverse effects of UA exposure on the liver. Its ability to restore redox balance and inhibit apoptosis makes it a promising candidate for countering the harmful effects of chemo-radiological agents such as UA.

U(VI) exposure induces apoptosis and pyroptosis in RAW264.7 cells

U(VI) pollution has already led to serious harm to the environment and human health with the increase of human activities. The viability of RAW264.7 cells was assessed under various U(VI) concentration stress for 24 and 48 h. The reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and superoxide dismutase (SOD) activities of RAW264.7 cells under U(VI) stress were measured. The results showed that U(VI) decreased cell activity, induced intracellular ROS production, abnormal MMP, and increased SOD activity. The flow cytometry with Annexin-V/PI double labeling demonstrated that the rate of late apoptosis increased with the increase of U(VI) concentration, resulting in decreased Bcl-2 expression and increased Bax expression. The morphology of RAW264.7 cells dramatically changed after 48 h U(VI) exposure, including the evident bubble phenomenon. Besides, U(VI) also increased the proportion of LDH releases and increased GSDMD, and Ras, p38, JNK, and ERK1/2 protein expression, which indicated that the MAPK pathway was also involved. Therefore, U(VI) ultimately led to apoptosis and pyroptosis in RAW264.7 cells. This study offered convincing proof of U(VI) immunotoxicity and established the theoretical framework for further fundamental studies on U(VI) toxicity.

Maternal exposure to dietary uranium causes oxidative stress and thyroid disruption in zebrafish offspring

The contamination of uranium in aquatic ecosystems has raised growing global concern. However, the understanding of its chronic effects on aquatic organisms is limited, particularly with regards to transgenerational toxicity. In this study, we evaluated the maternal transfer risk of uranium using zebrafish. Sexually mature female zebrafish were exposed to 2 and 20 ng/g of uranium-spiked food for 28 days. The induced bioconcentration, thyroid disruption, and oxidative stress in both the adults (F0) and their embryos (F1) were further investigated. Element analysis showed that uranium was present in both F0 and F1, with higher concentrations observed in F1, indicating significant maternal offloading to the offspring. Meanwhile, an increased malformation and decreased swim speed were observed in the F1. Thyroid hormone analysis revealed significant decreases in the levels of triiodothyronine (T3) in both the F0 adults and F1 embryos, but thyroxine (T4) was not significantly affected. Additionally, the activities of antioxidant defenses, including catalase (CAT) and superoxide dismutase (SOD), and the expression of glutathione (GSH) and malondialdehyde (MDA) were significantly altered in the F0 and F1 larvae at 120 hpf. The hypothalamic-pituitary-thyroid (HPT) axis, oxidative stress, and apoptosis-related gene transcription expression were also significantly affected in both generations. Taken together, these findings highlight the importance of considering maternal transfer in uranium risk assessments.

Characterization of Uranyl (UO22+) Ion Binding to Amyloid Beta (Aβ) Peptides: Effects on Aβ Structure and Aggregation

Uranium (U) is naturally present in ambient air, water, and soil, and depleted uranium (DU) is released into the environment via industrial and military activities. While the radiological damage from U is rather well understood, less is known about the chemical damage mechanisms, which dominate in DU. Heavy metal exposure is associated with numerous health conditions, including Alzheimer's disease (AD), the most prevalent age-related cause of dementia. The pathological hallmark of AD is the deposition of amyloid plaques, consisting mainly of amyloid-β (Aβ) peptides aggregated into amyloid fibrils in the brain. However, the toxic species in AD are likely oligomeric Aβ aggregates. Exposure to heavy metals such as Cd, Hg, Mn, and Pb is known to increase Aβ production, and these metals bind to Aβ peptides and modulate their aggregation. The possible effects of U in AD pathology have been sparsely studied. Here, we use biophysical techniques to study in vitro interactions between Aβ peptides and uranyl ions, UO22+, of DU. We show for the first time that uranyl ions bind to Aβ peptides with affinities in the micromolar range, induce structural changes in Aβ monomers and oligomers, and inhibit Aβ fibrillization. This suggests a possible link between AD and U exposure, which could be further explored by cell, animal, and epidemiological studies. General toxic mechanisms of uranyl ions could be modulation of protein folding, misfolding, and aggregation.

Uranium uptake is mediated markedly by clathrin-mediated endocytosis and induce dose-dependent toxicity in HK-2 cells

The objective of this study was to explore the endocytosis mechanisms of uranium uptake in HK-2 cells and its toxic effects. Our results demonstrated that uranium exposure impairs redox homeostasis and increases the permeability of the cell membrane and mitochondrial membrane, which may induce cell apoptosis by cytochrome-c leakage. Alkaline phosphatase activity increased after uranium exposure, which may be involved in the process of intracellular mineralisation of uranium, leading to severe cell necrosis. Furthermore, our findings demonstrated that the clathrin-mediated endocytosis process contributed substantially to uranium uptake in HK-2 cells and the total uranium uptake was highly correlated with cell viability, reaching a high correlation coefficient (r= -0.853) according to Pearson correlation analysis. In conclusion, the uptake of uranium into mammalian cells was mainly facilitated by the clathrin-mediated endocytosis pathway and induced dose-dependent cellular toxicity, including redox homeostasis imbalance, membrane injury, cell apoptosis and necrosis.

Cerium Oxide Nanorods Synthesized by Dalbergia sissoo Extract for Antioxidant, Cytotoxicity, and Photocatalytic Applications

In this study, cerium oxide nanorods (CeO₂-NRs) were synthesized by using the phytochemicals present in the Dalbergia sissoo extract. The physiochemical characteristics of the as-prepared CeO₂-NRs were investigated by using ultraviolet-visible spectroscopy (UV-VIS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction analysis (XRD). The SEM and UV-VIS analyses revealed that the acquired nanomaterials possessed a rod-like morphology while the XRD results further confirmed that the synthesized NRs exhibited a cubic crystal lattice system. The antioxidant capacity of the synthesized CeO₂-NRs was investigated by using several in vitro biochemical assays. It was observed that the synthesized NRs exhibited better antioxidant potential in comparison to the industrial antioxidant of the butylated hydroxyanisole (BHA) in 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The biochemical assays, including lipid peroxidation (LPO), total antioxidant capacity (TAC), and catalase activity (CAT), were also performed in the human lymphocytes incubated with the CeO₂-NRs to investigate the impact of the NRs on these oxidative biomarkers. Enhanced reductive capabilities were observed in all the assays, revealing that the NRs possess excellent antioxidant properties. Moreover, the cytotoxic potential of the CeO₂-NRs was also investigated with the MTT assay. The CeO₂-NRs were found to effectively kill off the cancerous cells (MCF-7 human breast cancer cell line), further indicating that the synthesized NRs exhibit anticancer potential as well. One of the major applications studied for the prepared CeO₂-NRs was performing the statistical optimization of the photocatalytic degradation reaction of the methyl orange (MO) dye. The reaction was optimized by using the technique of response surface methodology (RSM). This advanced approach facilitates the development of the predictive model on the basis of central composite design (CCD) for this degradation reaction. The maximum degradation of 99.31% was achieved at the experimental optimized conditions, which corresponded rather well with the predicted percentage degradation values of 99.58%. These results indicate that the developed predictive model can effectively explain the performed experimental reaction. To conclude, the CeO₂-NRs exhibited excellent results for multiple applications.

Cellular transport of uranium and its cytotoxicity effects on CHO-k1 cells

Uranium is a radioactive heavy metal and a significant public health concern; however, its associated underlying toxicological mechanisms remain largely unknown. In this work, the uptake and efflux processes of uranium in CHO-k1 cells were studied and the cytotoxicity effects were explored. It was found that both the uptake and efflux processes took place rapidly and half of the internalized uranium was expelled within 8 h. The uranium exposure caused a decrease of cell viability and adhesion ability in a dose-dependent manner and blocked the cell cycle at the G1 stage. In addition, gene expression analysis revealed relative changes in the transcription of metabolism related genes. Further studies revealed that the cytotoxicity of uranium could be alleviated by exposing cells to a lower temperature or by the addition of amantadine-HCl, an endocytosis inhibitor. Interestingly, after uranium exposure, needle-like precipitates were observed in both intracellular and extracellular regions. These findings collectively suggest that the cellular transport of uranium is a rapid process that disturbs cell metabolism and induces cytotoxicity, and this impact could be reduced by slowing down endocytic processes.

The immunotoxicity of natural and depleted uranium: From cells to people

Uranium is a naturally occurring element found in the environment as a mixture of isotopes with differing radioactive properties. Enrichment of mined material results in depleted uranium waste with substantially reduced radioactivity but retains the capacity for chemical toxicity. Uranium mine and milling waste are dispersed by wind and rain leading to environmental exposures through soil, air, and water contamination. Uranium exposure is associated with numerous adverse health outcomes in humans, yet there is limited understanding of the effects of depleted uranium on the immune system. The purpose of this review is to summarize findings on uranium immunotoxicity obtained from cell, rodent and human population studies. We also highlight how each model contributes to an understanding of mechanisms that lead to immunotoxicity and limitations inherent within each system. Information from population, animal, and laboratory studies will be needed to significantly expand our knowledge of the contributions of depleted uranium to immune dysregulation, which may then inform prevention or intervention measures for exposed communities.

Biosorption of Uranium from aqueous solution by green microalga Chlorella sorokiniana

Uranium and its compounds are radioactive and toxic, as well as highly polluting and damaging the environment. Novel uranium adsorbents with high biosorption capacity that are both eco-friendly and cost-effective are continuously being researched. The non-living biomass of the fresh water green microalga Chlorella sorokiniana was used to study the biosorption of uranium from aqueous solution. The biosorption of uranium from aqueous solutions onto the biomass of microalga C. sorokiniana was investigated in batch studies. The results showed that the optimal pH for uranium biosorption onto C. sorokiniana was 2.5. Uranium biosorption occurred quickly, with an equilibrium time of 90 min. The kinetics followed a pseudo-second-order rate equation, and the biosorption process fit the Langmuir isotherm model well, with a maximum monolayer adsorption capacity of 188.7 mg/g. The linear plot of the DKR model revealed that the mean free energy E = 14.8 kJ/mol, confirming chemisorption adsorption with ion exchange mode. The morphology of the algal biomass was investigated using a scanning electron microscope and energy dispersive X-ray spectroscopy. The FTIR spectroscopy analysis demonstrated that functional groups (carboxyl, amino, and hydroxyl) on the algal surface could contribute to the uranium biosorption process, which involves ion exchange and uranium absorption, and coordination mechanisms. Thermodynamic simulations indicated that the uranium biosorption process was exothermic (ΔH = -19.5562 kJ/mol) and spontaneous at lower temperatures. The current study revealed that C. sorokiniana non-living biomass could be an efficient, rapid, low-cost, and convenient method of removing uranium from aqueous solution.

Co-exposure of sodium arsenite and uranyl acetate differentially alters gene expression in CD3/CD28 activated CD4+ T-cells

Communities in the western region of the United States experience environmental exposure to metal mixtures from living in proximity to numerous unremediated abandoned uranium mines. Metals including arsenic and uranium co-occur in and around these sites at levels higher than the United States Environmental Protection Agency maximum contaminant levels. To address the potential effect of these metals on the activation of CD4+ T-cells, we used RNA sequencing methods to determine the effect of exposure to sodium arsenite (1 μM and 10 μM), uranyl acetate (3 μM and 30 μM) or a mixture of sodium arsenite and uranyl acetate (1 μM sodium arsenite + 3 μM uranyl acetate). Sodium arsenite induced a dose dependent effect on activation associated gene expression; targeting immune response genes at the lower dose. Increases in oxidative stress gene expression were observed with both sodium arsenite doses. While uranyl acetate alone did not significantly alter activation associated gene expression, the mixture of uranyl acetate with sodium arsenite demonstrated a combined effect relative to sodium arsenite alone. The results demonstrate the need to investigate metal and metalloid mixtures at environmentally relevant concentrations to better understand the toxicological impact of these mixtures on T-cell activation, function and immune dysregulation.

The mechanism of apoptosis of Chlamys farreri hemocytes under benzopyrene stress in vitro

Hemocytes are critical to the immune defense system of bivalves, and polycyclic aromatic hydrocarbons (PAHs) can mediate the immunity of bivalves by affecting the apoptosis of hemocytes. However, the underlying mechanism is still unclear. Chlamys farreri, as an important economic bivalve, was selected as the research subject for this experimentation. The hemocytes were exposed to typical PAHs-benzopyrene (B[a]P) in vitro to explore the apoptosis mechanism through detecting oxidative stress and oxidative damage-related indicators, apoptosis pathway factors, and apoptosis rate within 24 h. The results showed that the reactive oxygen species (ROS) and benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE) content in hemocytes increased significantly under B[a]P exposure, while antioxidant genes, glutathione peroxidase content and total antioxidant capacity all showed a trend of first rising and subsequent falling. B[a]P also caused serious damage to DNA and lysosomal membrane stability. The proapoptotic factors genes in the mitochondrial apoptosis pathway were significantly up-regulated, and the anti-apoptotic gene Bcl-2 was significantly down-regulated. Besides, mitochondrial membrane potential stability was significantly reduced and caspase 9 enzyme activity was significantly improved with the B[a]P stimulation. The factors of death receptor pathway were also significantly up-regulated by B[a]P. Moreover, the expression levels of Mitogen-Activated Protein Kinases were also induced. The gene expression and enzyme activity of the caspase 3 and the apoptosis rate were significantly increased under B[a]P exposure. In conclusion, these results indicated that ROS was induced by B[a]P, and further triggered the oxidative stress and oxidative damage in hemocytes. B[a]P induced hemocyte apoptosis was mediated by both mitochondrial apoptosis pathway and death receptor apoptosis, and the activation of mitochondrial apoptosis pathway was affected by ROS. In addition, BPDE and MAPKs may play important roles in the B[a]P-mediated apoptosis pathway. This study deepens understanding of the apoptosis pathway and the immunotoxicity mechanism in bivalves hemocytes stimulated by persistent organic pollutants.

Nutraceuticals as Potential Radionuclide Decorporation Agents

Exposure of individuals to radioactive material as a result of ingestion of contaminated food and water is an increasing public health concern. Unfortunately, there are limited treatment modalities for dealing with these types of potentially toxic exposures. Recent research suggests that many plant-based nutraceuticals may possess metal-binding properties. This preliminary study investigated the ability of genistein, curcumin, quercetin, and lentinan to bind metals considered internal contamination risks, namely cesium, uranium, cobalt, and strontium, in a variety of matrices. The efficacy of these nutraceuticals in protecting cultured cells from metal-induced toxicity was also explored. Results showed that none of the compounds bound cesium or strontium. However, genistein, curcumin, and quercetin could bind uranium. Curcumin and quercetin also bound cobalt and could also protect cultured cells from metal-induced cytotoxicity. Lentinan did not bind any of the metals tested. Metal binding was also pH dependent, with no binding observed at lower pH values. This project showed that nutraceuticals could function as chelators for metals considered internal radionuclide contamination hazards. Further investigations are required in order to determine whether these compounds will become a new nontoxic arsenal of pharmaceutical compounds with which to treat radionuclide contamination.

Differences in susceptibility of HT-29 and A549 cells to statin-induced toxicity: An investigation using high content screening

Statins are a group of hydroxymethylglutaryl coenzyme A reductase inhibitors that are used in the treatment of cardiovascular diseases. However, statins have been found to be cytotoxic, and many unexpected side effects have been reported in clinical applications. The susceptibilities of different cell lines toward statins are diverse, and the mechanisms of cytotoxicity remain unknown. Therefore, the present study aimed to investigate differences in the susceptibility to and mechanisms of statin-induced cytotoxicity in two cell lines, HT-29 and A549, using a high content screening-based multiparametric toxicity assay panel. We found that the two cell types exhibited differing susceptibilities to the cytotoxic effects of the different statins. Additionally, the cytotoxicity was inconsistent between different statins in the two cell lines. Four statins with strong cytotoxicity decreased the viability of HT-29 cells via the mitochondrial pathway, as evidenced by decreased mitochondrial membrane potential, and elevated mitochondrial mass, calcium release and cell apoptosis, and reactive oxygen species. In contrast, these four statins only induced a decrease in the mitochondrial membrane potential in A549 cells. The above results provide an objective reason for future evaluations of cytotoxic differences in cell types and the underlying mechanisms of cytotoxicity in different statins, and provide a good scientific basis for further research on countermeasures against statin-induced cell injuries.

A toxicological comparison between two uranium compounds in Artemia salina: Artificial seawater containing CaCO3

Uranium (U) mining is an aquatic environmental concern because most of these harmful compounds are discharged into freshwater, reaching the saline environment as the final destination of this contaminated water. Carbonates are present in ocean waters and are essential for benthic organisms, however they may influence the U-induced toxicity. Thus, the aim of this study was to compare the toxicity of uranium nitrate (UN) and uranium acetate (UA) in Artemia salina (AS), which is one of the leading representatives of the marine biota. The cultures of AS (instar II) maintained in artificial seawater containing CaCO₃ were exposed for 24 h to different concentrations of U compounds. The results showed that AS were more sensitive to UN (LC₅₀ ≈ 15 μM) when compared with UA (LC₅₀ ≈ 245 μM) indicating higher toxicity of this U compound. Calculated U speciation indicated that Ca₂UO₂(CO₃)₃ and (UO₂)2CO₃(OH)₃^- complexes predominated under our experimental conditions. The immobilization/lethality was observed after 9 h of exposure for both U compounds. However, only UN caused a significant decrease (≈40%) in the acetylcholinesterase (AChE) activity when compared with control. In order to observe preliminary toxicity effects, we evaluated oxidative stress parameters, such as catalase (CAT) activity, TBARS formation, radical species (RS) generation and cell membrane injury and/or apoptosis (CMI). In this study, we demonstrate that U compounds caused a significant decrease in CAT activity. Similarly, we also observed that UN increased TBARS levels in AS at concentrations 5 times lower than AU (10 μM and 50 μM, respectively). Furthermore, RS generation and CMI were enhanced only on AS treated with UN. Overall, the effects observed here were remarkably significant in AS exposed to UN when compared with AU. In this study, we showed different profiles of toxicity for both U compounds, contributing significantly to the current and scarce understanding of the aquatic ecotoxicity of this heavy metal.

Chronic oral depleted uranium leads to reproductive damage in male rats through the ROS-hnRNP A2/B1-COX-2 signaling pathway

Depleted uranium (DU) is widely used in civil and military activities. The testis is one of the target organs of DU chronic toxicity. In this study, male SD rats were chronically exposed to DU by 3, 30, 300 mg U/kg through oral intake. After 6 months and 12 months of exposure, it was found that DU could lead to increased oxidative stress levels, decreased glutathione S-transferases (GSTs) expression, resulting in testicular injury and decreased serum testosterone (T) level in rats. Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) expression increases with the increase of DU exposure dose. After upregulation of hnRNP A2/B1 expression, the GC-1 cell injury caused by DU is aggravated, suggesting that hnRNP A2/B1 may play an important role in the reproductive toxicity of DU. At the same time, 12 months after chronic oral exposure to DU, the expression level of cyclooxygenase-2 (COX-2) and proinflammatory factor prostaglandin E2 (PGE2) in testicular tissue were increased, and the level of hnRNP A2/B1 caused by DU was decreased by reactive oxygen scavenger N-acetylcysteine (NAC). As hnRNP A2/B1 is a COX-2 regulator, DU may lead to the upregulation of hnRNP A2/B1 expression through the increase of oxidative stress level in germ cells, which in turn leads to the increase of COX-2 and PGE2 level, and ultimately result in the reproductive toxicity. In this study, the regulation mechanism of the ROS-hnRNP A2/B1-COX-2 pathway on DU-induced reproductive damage in male rats was hypothesized, providing a new target for the prevention and treatment of chronic poisoning of DU.

Effective biosorption of uranium from aqueous solution by cyanobacterium Anabaena flos-aquae

Anabaena flos-aquae, a typical species of cyanobacterial bloom, was employed as a useful biosorbent for uranium removal. Batch experiments were conducted to examine the effects of different parameters on the uranium uptake amount of Anabaena flos-aquae. The maximum adsorption capacity of 196.4 mg/g was obtained under the optimized experimental conditions. The calculations of kinetic and thermodynamic results proved the adsorption process was endothermic, chemisorption, and spontaneous. The adsorption of uranium onto Anabaena flos-aquae was better defined by the Langmuir model, which indicated the process was a monolayer sorption. In addition, the characterization of the biosorbent before and after uranium sorption implied that the dominant functional groups participated in the uranium adsorption process were hydroxyl, amino, and carboxyl. In conclusion, the environmentally friendly and biocompatible characteristics of Anabaena flos-aquae suggest that it can be a promising biosorbent for uranium removal.

A review of biological effects and treatments of inhaled depleted uranium aerosol

Depleted uranium (DU) is primarily used for DU bombs and DU tanks in the military. Aerosol inhalation is considered the primary route of DU exposure. Although laboratory tests have confirmed that inhalation of DU aerosol can cause lung, kidney, and other organ damage, epidemiological studies have found no conclusive evidence that persons in areas with prolonged exposure to DU-containing bombs are affected. After the body inhaled DU aerosols, we first clear the insoluble DU through whole-lung lavage (WLL). Then we eliminate the soluble uranium by the chelating agent. Besides, reducing DU damage to tissues and cells through drugs is also an important treatment method. In future research, emphasis should be placed on the damage mechanism of DU aerosol, the laboratory and clinical research of DU chelating agents, the research on the combination of DU chelating agent and WLL, and the research and development of new drugs to prevent DU damage.

Efficient removal of U(VI) from aqueous solutions using the magnetic biochar derived from the biomass of a bloom-forming cyanobacterium (Microcystis aeruginosa)

The utilization of Microcystis biomass is an urgent issue in the mitigation of cyanobacterial bloom. In this study, Microcystis-derived biochar (MB) and Fe₃O₄-modified biochar (Fe₃O₄/MB) were fabricated for the U(VI) elimination. The results showed that U(VI) sorption process by either MB or Fe₃O₄/MB was pH-dependent and ionic strength-independent. The maximum sorption capacity of MB was higher than that of Fe₃O₄/MB. According to the analysis of X-ray photoelectron spectroscopy, U(VI) sorption on both MB and Fe₃O₄/MB was mainly ascribed to the surface complexation between U(VI) and oxygen-containing functional groups on the surface of MB. Fe₃O₄ particles on the surface of MB didn't provide extra active sites for the sorption of U(VI), but it enabled the adsorbent to be magnetically separated. Five consecutive sorption/desorption cycles verified the good reusability of Fe₃O₄/MB in this study. Therefore, the investigation is not only meaningful for the utilization of nuisance biomass from cyanobacterial blooms, but also provides novel adsorbents for the U(VI) removal from aqueous solutions.

A Review of Uranium-Induced Reproductive Toxicity

As a heavy metal nuclear fuel, uranium is used in various civil and military projects, resulting in environmental pollution. Uranium can enter the body through the mouth, nose and skin, threatening human health. The reproductive organs are sensitive to uranium. For certain exposure times, doses and modes, uranium can produce toxic effects on the reproductive organs. The reproductive toxicity of uranium can be produced through different mechanisms of action, such as changing the level of sex hormones in the body, disrupting the expression of genes or proteins related to reproduction and causing oxidative stress and inflammation. Uranium thus can cause toxic effects to the reproductive system, leading to histopathological changes and decreased conception rates, and may damage the health of the body. This paper reviews the research progress on uranium reproductive toxicity in recent years and indicates a direction for future research on uranium reproductive toxicity and its mechanisms.

Effects of quercetin loaded nanostructured lipid carriers on the paraquat-induced toxicity in human lymphocytes

Paraquat (PQ) as a herbicide and an environmental pollutant with increasing importance due to its toxicity to humans and animals. This study aimed to evaluate the protective and antioxidant activity of quercetin loaded Nanostructured Lipid Carriers (QNLC) against toxicity induced by PQ. Blood lymphocytes were prepared using Ficoll polysaccharide and subsequently by gradient centrifugation. The QNLC was prepared using an ultra-sonication method, which was characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The viability, reactive oxygen species (ROS), lipid peroxidation (LPO), mitochondrial membrane potential (MMP), lysosome membrane integrity, Bax and Bcl2 gene expression were evaluated in human isolated lymphocytes. The results showed spherical QNLCs with nano-size range (52.7 nm) and high drug encapsulation efficiency (98.5% -96%). The results also indicated that PQ induced cell death, as well as ROS production, decreased by QNLC in human lymphocytes. Also, QNLC meaningfully restored MMP reduction, lysosomal membrane destabilization, and lipid peroxidation and were capable of preventing PQ-treated change in Bax and Bcl2 gene expression. We report that QNLC, have a significantly higher capacity to prevent PQ-induced toxicity than Q itself. It is suggested that the QNLC is a promising antioxidant for drug delivery to be used as a therapeutic and prophylactic agent for PQ poisoning.