Hexavalent chromium induces mitochondrial dynamics disorder in rat liver by inhibiting AMPK/PGC-1α signaling pathway

Therapeutic Potential of Aloe vera and Aloe vera-Conjugated Silver Nanoparticles on Mice Exposed to Hexavalent Chromium

Hexavalent chromium (Cr (VI)) is a hazardous heavy metal that induces hepatotoxicity and nephrotoxicity. Thus, this study was planned to explore the ameliorating capacity of Aloe vera leaf gel extract (AV) and their conjugated silver nanoparticles (AVNP) against Cr (VI) induced hepatotoxicity and renal toxicity. The organ indices, level of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, malondialdehyde, total protein, and creatinine in blood serum were measured. The histopathological and micrometric analysis of the hepatic and renal tissue sections were studied. The hepatosomatic index was raised significantly (0.098 ± 0.13 g) in Cr treated group. The blood serum level of AST (484 ± 10.7 U/L), ALT (163 ± 5.5 U/L), ALP (336.7 ± 9.5 U/L), MDA (642.3 ± 28.3 U/L), and creatinine (4.0 ± 0.1 mg/dL) were increased significantly, whereas total protein level was declined (2.8 ± 0.3 g/dL) significantly in Cr exposed group. In the histopathological study, necrosis, disturbed hepatic cords, impaired glomeruli, and Bowman's capsule were noted. Micrometric data from the liver and kidney revealed a significant surge in the size of hepatocytes and their nuclei (1188.2 ± 467.7 µ2 and 456.5 ± 205.6 µ2) and CSA of glomeruli and Bowman's capsule (9051.8 ± 249.8 µ2 and 11,835.5 ± 336.7 µ2) in Cr (VI) exposed group, whereas the brush border (10.2 ± 4.0 µ) size declined significantly. The administration of AV and AVNP reduced the oxidative stress induced by Cr (VI).

Hexavalent chromium damages intestinal cells and coelomocytes and impairs immune function in the echiuran worm Urechis unicinctus by causing oxidative stress and apoptosis

Hexavalent chromium (Cr(VI)) is a common pollutant in the marine environment, which impairs immunity and causes reproductive and heredity disorders in organisms. To clarify the immunotoxic effects of Cr (VI) on the marine worm Urechis unicinctus, we analyzed tissue damage and immune dysfunction caused by Cr (VI) in this organism at histopathologic, zymologic, apoptotic and molecular levels. The results indicated that the bioaccumulation of Cr (VI) bioaccumulation levels in coelomocytes was significantly higher than in the intestines and muscles. Pathological observation showed that Cr (VI) caused damage to the respiratory intestine, stomach and midgut. Cr (VI) also increased the replication of goblet cells and a reduction in the replication of epithelial cells. Meanwhile, Cr (VI) induced apoptosis of intestinal cells and coelomocytes, accompanied by an increase in the expression of Caspase-3, COX-2, and MyD88 in the intestine and coelomocytes. At the same time, Cr (VI) significantly affected the activities of antioxidant enzymes such as SOD, ACP, CAT, CAT, and GST, and increased H2O2 and MDA contents in U. unicinctus. Moreover, Cr (VI) exposure also up-regulated the transcription of hsc70, mt and jnk genes but decreased that of sod in the intestines. In contrast, Cr (VI) down-regulated the expression of sod, hsc70, mt, and jnk genes in coelomocytes. Collectively, Cr (VI) bioaccumulated in U. unicinctus cells and tissues, causing several histopathological changes, oxidative stress, and apoptosis of several cells in the organism, resulting in intestinal and coelomocyte damage and immune dysfunctioning.

Air pollutants as modulators of mitochondrial quality control in cardiovascular disease

It is important to understand the effects of environmental factors such as air pollution on mitochondrial structure and function, especially when these changes increase cardiovascular disease risk. Although lifestyle choices directly determine many mitochondrial diseases, increasingly, it is becoming clear that the structure and function of mitochondria may be affected by pollutants found in the atmosphere (e.g., gases, pesticides herbicide aerosols, or microparticles). To date, the role of such agents on mitochondria and the potential impact on cardiovascular fitness is neglected. Here we offer a review of airborne stressors and pollutants, that may contribute to impairments in mitochondrial function and structure to cause heart disease.

Low-Dose Hexavalent Chromium Exposure Induces Endoplasmic Reticulum Stress-Mediated Apoptosis in Rat Liver

This study investigated the toxic effects of low-dose hexavalent chromium (Cr(VI)) on rat liver. Male specific pathogen-free (SPF) Sprague-Dawley (SD) rats (4-5 weeks of age) were randomly divided into groups: saline, 0.05 mg/kg Cr(VI), and 0.25 mg/kg Cr(VI). The rats were subjected to intratracheal instillation of K2Cr2O7 suspensions or saline once weekly, for a total of five times. The results showed that the accumulation of Cr(VI) in the blood of the 0.25 mg/kg K2Cr2O7 group was significantly higher than that in the saline group. Transmission electron microscopy (TEM) showed that exposure to hexavalent chromium caused endoplasmic reticulum (ER) oedema and a disordered arrangement. The levels of endoplasmic reticulum stress (ERS)-related proteins (ATF6, P-PERK, P-IRE1, Grp78, and CHOP) in the 0.25 mg/kg K2Cr2O7 group were significantly higher than those in the saline group. The expression of apoptosis-inhibitory protein Bcl-2 was significantly lower in the 0.25 mg/kg K2Cr2O7 group than that in the saline group, and the expression of apoptosis protein Bax was significantly higher in the 0.25 mg/kg K2Cr2O7 group than that in the saline group, indicating that Cr(VI) increased apoptosis. These findings revealed that Cr(VI) may be involved in rat liver injury by initiating ERS-mediated apoptosis. The expression of ATF6, P-PERK, P-IRE1, and Bax in the 0.05 mg/kg K2Cr2O7 group was not significantly different from that in the saline group, and the different effects produced by the two different dose groups provide a possible experimental basis for further study of occupational exposure limits.

Chromium Affects Mitochondrial Function, Leading to Apoptosis and Autophagy in Turtle Primary Hepatocytes

Hexavalent chromium (Cr(VI)), a pervasive industrial contaminant, is highly toxic to both humans and animals. However, its effects on turtles are largely unexplored. Our study aimed to investigate the toxic effects of Cr(VI) on the Reeves' turtles (Mauremys reevesii) primary hepatocytes. We exposed hepatocytes to two concentrations (25 μM and 50 μM) of Cr(VI) for 24 h. The results showed that compared to controls, Cr(VI)-treated cells showed elevated antioxidant enzyme activity (catalase (CAT) and superoxide dismutase (SOD)) and increased reactive oxygen species (ROS) levels. Adenosine triphosphatae (ATP) levels decreased, indicating mitochondrial dysfunction. Additionally, we found significant changes in mitochondrial dynamics related genes, with downregulation of mitofusin 2 (Mfn2) and silent information regulator 1 (SIRT1) and a decrease in sirtuin 3 (SIRT3) and tumor protein 53 (p53) mRNA levels. Annexin V-FITC fluorescence staining-positive cells increased with higher Cr(VI) concentrations, marked by elevated bcl-2-associated X protein (Bax) and cysteinyl aspartate specific proteinase (Caspase3) mRNA levels and reduced B-cell lymphoma-2 (Bcl2) expression. Autophagy-related genes were also affected, with increased microtubule-associated protein 1 light chain 3 (LC3-I), microtubule-associated protein light chain 3II (LC3-II), unc-51-like autophagy-activating kinase 1 (ULK1), and sequestosome 1 (p62/SQSTM1) mRNA levels and decreased mammalian target of rapamycin (mTOR) and Beclin1 expression. Taken together, Cr(VI) promotes cell apoptosis and autophagy in turtle hepatocytes by inducing oxidative stress and disrupting mitochondrial function. These findings highlight the serious health risks posed by Cr(VI) pollution and emphasize the need for protecting wild turtle populations.

Mechanism of Mitochondrial Kinetic Imbalance and Nrf2 Signaling Pathway-Mediated Oxidative Stress in Nickel and/or Chromium-Induced Kidney Injury in Mice

Nickel and chromium are both common heavy metals that pose serious environmental and health hazards. However, the exact mechanism by which nickel and/or chromium cause renal injury is unclear. Therefore, we explored the molecular mechanisms of renal injury caused by nickel and/or chromium poisoning from the perspective of mitochondrial dynamics and the Nrf2 antioxidant pathway. In this study, eighty 6-week-old C57BL/6J mice were randomly divided into four groups: control (Con, untreated), nickel (Ni, 110 mg/L Ni2+), chromium (Cr, 50 mg/L Cr6+), and combined nickel-chromium (Ni + Cr, 110 mg/L Ni2+, 50 mg/L Cr6+). The results showed that chronic nickel and/or chromium exposure inhibited body weight gain and impaired kidney function and structure in mice. Chronic nickel and/or chromium exposure led to the disruption of mitochondrial dynamics and thus induced oxidative stress. On the other hand, the Nrf2 antioxidant pathway may play an important regulatory role in mitigating oxidative stress-induced oxidative damage in kidney. The present study partially elucidated the molecular mechanism of renal injury induced by nickel and/or chromium exposure in mice and the regulatory role of the Nrf2 pathway in inducing oxidative injury from the perspective of mitochondrial dynamics. This provides a theoretical basis for the development of prevention and control strategies, and environmental protection measures.

Protective effect and mechanism of Lycium ruthenicum Murray anthocyanins against retinal damage induced by blue light exposure

Lycium ruthenicum Murray (LR) is a medicine and edible plant in Northwest China, and L. ruthenicum Murray anthocyanins (LRA) are green antioxidants with various pharmacological activities, such as antioxidant and anti-inflammatory activities. However, the protective effect and mechanism of LRA against retinal damage induced by blue light exposure are poorly understood. This study explored the protective effects and potential mechanisms of LRA on retinal damage induced by blue light exposure in vitro and in vivo. The results showed that LRA could ameliorate oxidative stress injury by activating the antioxidant stress nuclear factor-related factor 2 pathway, promoting the expression of phase II detoxification enzymes (HO-1, NQO1) and endogenous antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase), and reducing reactive oxygen species and malondialdehyde levels. Additionally, LRA could inhibit inflammatory response by decreasing the expression of blue light exposure-induced nuclear factor-κB (NF-κB) pathway-related proteins (NF-κB and p-IκBα), as well as interleukin (IL)-6, tumor necrosis factor-α, IL-1β pro-inflammatory factors and pro-inflammatory chemokine VEGF, and increasing the expression of anti-inflammatory factor IL-10. Furthermore, LRA could ameliorate oxidative stress-induced apoptosis by upregulating Bcl-2 and downregulating Bax and Caspase-3 protein expression. All these results indicate that LRA can be used as an antioxidant dietary supplement for the treatment or prevention of retinal diseases.

Prosthetic Metals: Release, Metabolism and Toxicity

The development of metallic joint prostheses has been ongoing for more than a century alongside advancements in hip and knee arthroplasty. Among the materials utilized, the Cobalt-Chromium-Molybdenum (Co-Cr-Mo) and Titanium-Aluminum-Vanadium (Ti-Al-V) alloys are predominant in joint prosthesis construction, predominantly due to their commendable biocompatibility, mechanical strength, and corrosion resistance. Nonetheless, over time, the physical wear, electrochemical corrosion, and inflammation induced by these alloys that occur post-implantation can cause the release of various metallic components. The released metals can then flow and metabolize in vivo, subsequently causing potential local or systemic harm. This review first details joint prosthesis development and acknowledges the release of prosthetic metals. Second, we outline the metallic concentration, biodistribution, and elimination pathways of the released prosthetic metals. Lastly, we discuss the possible organ, cellular, critical biomolecules, and significant signaling pathway toxicities and adverse effects that arise from exposure to these metals.

The active components and potential mechanisms of Wuji Wan in the treatment of ethanol-induced gastric ulcer: An integrated metabolomics, network pharmacology and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Wuji Wan (WJW) is a traditional Chinese medicine formula that can be found in the "Prescriptions of Taiping Benevolent Dispensary" that has been employed in treating gastric discomfort, burning epigastric pain, and gastric reflux for hundreds of years and has shown promise for treating gastric ulcers (GUs). However, the active components and mechanism of action against GUs remain unclear.

AIM OF THE STUDY

The aim of this study was to explore the active components of WJW and elucidate the underlying mechanism involved in treating GUs.

MATERIALS AND METHODS

Initially, cell viability was measured by a cell counting kit 8 (CCK-8) assay to evaluate the efficacy of WJW-containing serum in vitro. The gastric ulcer index, ulcer inhibition rate, hematoxylin and staining (H&E), and periodic acid-Schiff (PAS) staining were used to evaluate the therapeutic effect of WJW in vivo. Subsequently, the levels of inflammatory factors and oxidative stress factors were determined using an enzyme-linked immunosorbent assays (ELISA) on in vitro and in vivo samples. Additionally, UPLC-Q Exactive Plus Orbitrap HRMS was used to analyze the components that were absorbed into the blood of WJW and its metabolites. Network pharmacology and metabolomics were subsequently used to identify the targets and pathways. Real-time quantitative PCR (RT‒qPCR) and Western blotting were used to verify the mRNA and protein levels of the key targets and pathways. Finally, the active components were identified by molecular docking to verify the binding stability of the components and key targets.

RESULTS

WJW-containing serum ameliorated ethanol-induced damage in GES-1 cells and promoted cell healing. WJW-containing serum reduced IL-6, TNF-α, MDA, and LDH levels while increasing IL-10, SOD, and T-AOC levels in the cells. Moreover, WJW treatment resulted in decreased IL-6, TNF-α, and MDA levels and increased IL-10, SOD, PGE2, and NO levels in GUs rats. In addition, eight components of WJW were absorbed into the blood. The network pharmacology results revealed 192 common targets for blood entry components and GUs, and KEGG analysis revealed that apoptosis signaling pathways were the main pathways involved in WJW activity against GUs. Metabolomic screening was used to identify 13 differential metabolites. There were 23 common targets for blood entry components, GUs, and differential metabolites, with the key targets TNF (TNF-α), AKT1, PTGS2 (COX2) and MAPK1. WJW significantly inhibited the expression of Bax, Caspase-9, Caspase-3, cleaved Caspase-9, cleaved Caspase-3, TNF-α, COX2, and p-p44/42 MAPK while promoting the expression of Bcl-2 and p-AKT1. Molecular docking revealed that the active components of WJW for the treatment of GUs are berberine, palmatine, coptisine, evodiamine, rutaecarpine, evocarpine, and paeoniflorin.

CONCLUSIONS

WJW treatment reduces inflammation and oxidative stress injury and inhibits apoptosis signaling pathways. The main active components are berberine, palmatine, coptisine, evodiamine, rutaecarpine, evocarpine, and paeoniflorin. In this paper, we provide a new strategy for exploring the active components of traditional Chinese medicine formulas for the treatment of diseases based on target mechanisms.

Dendrobium officinale polysaccharide alleviates thiacloprid-induced kidney injury in quails via activating the Nrf2/HO-1 pathway

Thiacloprid (THI) is a neonicotinoid insecticide, and its wide-ranging use has contributed to severe environmental and health problems. Dendrobium officinale polysaccharide (DOP) possesses multiple biological activities such as antioxidant and antiapoptosis effect. Although present research has shown that THI causes kidney injury, the exact molecular mechanism and treatment of THI-induced kidney injury remain unclear. The study aimed to investigate if DOP could alleviate THI-induced kidney injury and identify the potential molecular mechanism in quails. In this study, Japanese quails received DOP (200 mg/kg) daily with or without THI (4 mg/kg) exposure for 42 days. Our results showed that DOP improved hematological changes, biochemical indexes, and nephric histopathological changes induced by THI. Meanwhile, THI exposure caused oxidative stress, apoptosis, and autophagy. Furthermore, THI and DOP cotreatment significantly activated the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) pathway, restored antioxidant enzyme activity, and reduced apoptosis and autophagy in quail kidneys. In summary, our study demonstrated that DOP mitigated THI-mediated kidney injury was associated with oxidative stress, apoptosis, and autophagy via activation of the Nrf2/HO-1 signaling pathway in quails.

Echinacea purpurea root extract mitigates hepatotoxicity, genotoxicity, and ultrastructural changes induced by hexavalent chromium via oxidative stress suppression

Environmental and occupational exposure to hexavalent chromium (CrVI) is mostly renowned as a possible hepatotoxic in mammals. Echinacea purpurea (L.) Moench, a phenolic-rich plant, is recurrently used for its therapeutic properties. Therefore, this investigation was done to explore whether E. purpurea (EP) root extract would have any potential health benefits against an acute dose of CrVI-induced oxidative damage and hepatotoxicity. Results revealed that GC-MS analysis of EP root extract has 26 identified components with a significant amount of total phenolic and flavonoid contents. Twenty-four Male Wistar rats were divided into four groups: control, EP (50 mg/kg BW/day for 21 days), CrVI (15 mg/kg BW as a single intraperitoneal dosage), and EP + CrVI, respectively. Rats treated with CrVI displayed a remarkable rise in oxidative stress markers (TBARS, H2O2, PCC), bilirubin, and lactate dehydrogenase activity, and a marked decrease in enzymatic and non-enzymatic antioxidants, transaminases, and alkaline phosphatase activities, and serum protein level. Also, CrVI administration induced apoptosis and inflammation in addition to histological and ultrastructural abnormalities in the liver tissue. The examined parameters were improved significantly in rats pretreated with EP and then intoxicated with CrVI. Conclusively, EP had a potent antioxidant activity and could be used in the modulation of CrVI-induced hepatotoxicity.

Effects of hexavalent chromium on mitochondria and their implications in carcinogenesis

Hexavalent chromium (Cr(VI)) is a well-known occupational and environmental human carcinogen. The cellular effect of Cr(VI) is complex and often nonspecific due to its ability to modulate multiple cellular targets. The toxicity of Cr(VI) is strongly linked to the generation of reactive oxygen species (ROS) during its reduction process. ROS can cause oxidation of cellular macromolecules, such as proteins, lipids, and DNA, thereby altering their functions. A major genotoxic effect of Cr(VI) that contributes to carcinogenesis is the formation of DNA adducts, which can lead to DNA damage. Modulations of cellular signaling pathways and epigenetics may also contribute to the carcinogenic effects of Cr(VI). Cr(VI) has a major impact on many aspects of mitochondrial biology, including oxidative phosphorylation, mitophagy, and mitochondrial biogenesis. These effects have the potential to alter the trajectory of Cr(VI)-induced carcinogenic process. This perspective article summarizes current understandings of the effect of Cr(VI) on mitochondria and discusses the future directions of research in this area, particularly with regard to carcinogenesis.

Hexavalent-Chromium-Induced Disruption of Mitochondrial Dynamics and Apoptosis in the Liver via the AMPK-PGC-1α Pathway in Ducks

Hexavalent chromium (Cr(VI)) is a hazardous substance that poses significant risks to environmental ecosystems and animal organisms. However, the specific consequences of Cr(VI) exposure in terms of liver damage remain incompletely understood. This study aims to elucidate the mechanism by which Cr(VI) disrupts mitochondrial dynamics, leading to hepatic injury in ducks. Forty-eight healthy 8-day-old ducks were divided into four groups and subjected to diets containing varying doses of Cr(VI) (0, 9.28, 46.4, and 232 mg/kg) for 49 days. Our results demonstrated that Cr(VI) exposure resulted in disarranged liver lobular vacuolation, along with increasing the serum levels of ALT, AST, and AKP in a dose-dependent manner, which indicated liver damage. Furthermore, Cr(VI) exposure induced oxidative stress by reducing the activities of T-SOD, SOD, GSH-Px, GSH, and CAT, while increasing the contents of MDA and H2O2. Moreover, Cr(VI) exposure downregulated the activities of CS and MDH, resulting in energy disturbance, as evidenced by the reduced AMPK/p-AMPK ratio and PGC-1α protein expression. Additionally, Cr(VI) exposure disrupted mitochondrial dynamics through decreased expression of OPA1, Mfn1, and Mfn2 and increased expression of Drp-1, Fis1, and MFF proteins. This disruption ultimately triggered mitochondria-mediated apoptosis, as evidenced by elevated levels of caspase-3, Cyt C, and Bax, along with decreased expression of Bcl-2 and the Bcl-2/Bax ratio, at both the protein and mRNA levels. In summary, this study highlights that Cr(VI) exposure induces oxidative stress, inhibits the AMPK-PGC-1α pathway, disrupts mitochondrial dynamics, and triggers liver cell apoptosis in ducks.

Effect of hexavalent chromium exposure on the reproductive status and biomarker responses of female Geloina erosa

Hexavalent chromium (Cr (VI)) is widely distributed in the marine environment of Hainan Province, China and poses a potential threat to its mangrove ecosystems. However, the mechanisms underlying Cr-induced stress and reproductive toxicity in clams remain largely unknown. In this study, the clams, Geloina erosa, were exposed to 4.34, 8.69, 17.38 and 34.76 mg/L Cr (VI) for 24, 48 and 72 h. The gonad-somatic index (GSI) was determined and histological alterations of the ovaries were quantified by light microscopy. The micronucleus test was performed which quantifies the genotoxic presence of small cytoplasmic bodies in eukaryotic cells. Enzymatic assays for catalase (CAT), glutathione reductase (GR), and malondialdehyde (MDA) activities were done. Quantitative real-time PCR (qRT-PCR) was used to quantify the expression of glutathione-S-transferase (GST), heat shock protein 70 (HSP70) and vitellogenin (Vtg) in ovaries of G. erosa. The results showed that the micronucleus frequency was significantly increased when clams were exposed to Cr (VI). Cr (VI) exposure induced the accumulation of MDA and affected CAT and GR enzyme activities. The high Cr (VI) concentration of 34.76 mg/L significantly increased the levels of GR activity, GST expression and HSP70 expression and inhibited Vtg expression and CAT activity. MDA content was significantly increased after 72 h at the high Cr (VI) exposure (34.76 mg/L). Therefore, Cr (VI) exposure may be toxic to the development of ovaries of G. erosa.

A review of chromium (Cr) epigenetic toxicity and health hazards

Carcinogenic metals affect a variety of cellular processes, causing oxidative stress and cancer. The widespread distribution of these metals caused by industrial, residential, agricultural, medical, and technical activities raises concern for adverse environmental and human health effects. Of these metals, chromium (Cr) and its derivatives, including Cr(VI)-induced, are of a public health concern as they cause DNA epigenetic alterations resulting in heritable changes in gene expression. Here, we review and discuss the role of Cr(VI) in epigenetic changes, including DNA methylation, histone modifications, micro-RNA changes, biomarkers of exposure and toxicity, and highlight prevention and intervention strategies to protect susceptible populations from exposure and adverse occupational health effects. Cr(VI) is a ubiquitous toxin linked to cardiovascular, developmental, neurological, and endocrine diseases as well as immunologic disorders and a high number of cancer types in humans following inhalation and skin contact. Cr alters DNA methylation levels as well as global and gene-specific histone posttranslational modifications, emphasizing the importance of considering epigenetics as a possible mechanism underlying Cr(VI) toxicity and cell-transforming ability. Our review shows that determining the levels of Cr(VI) in occupational workers is a crucial first step in shielding health problems, including cancer and other disorders. More clinical and preventative measures are therefore needed to better understand the toxicity and safeguard employees against cancer.

Biogeochemical behaviour and toxicology of chromium in the soil-water-human nexus: A review

Chromium (Cr) affects human health if it accumulates in organs to elevated concentrations. The toxicity risk of Cr in the ecosphere depends upon the dominant Cr species and their bioavailability in the lithosphere, hydrosphere, and biosphere. However, the soil-water-human nexus that controls the biogeochemical behaviour of Cr and its potential toxicity is not fully understood. This paper synthesizes information on different dimensions of Cr ecotoxicological hazards in the soil and water and their subsequent effects on human health. The various routes of environmental exposure of Cr to humans and other organisms are also discussed. Human exposure to Cr(VI) causes both carcinogenic and non-carcinogenic health effects via complicated reactions that include oxidative stress, chromosomal and DNA damage, and mutagenesis. Chromium (VI) inhalation can cause lung cancer; however, incidences of other types of cancer following Cr(VI) exposure are low but probable. The non-carcinogenic health consequences of Cr(VI) exposure are primarily respiratory and cutaneous. Research on the biogeochemical behaviour of Cr and its toxicological hazards on human and other biological routes is therefore urgently needed to develop a holistic approach to understanding the soil-water-human nexus that controls the toxicological hazards of Cr and its detoxification.

Combined β-sitosterol and trimetazidine mitigate potassium dichromate-induced cardiotoxicity in rats through the interplay between NF-κB/AMPK/mTOR/TLR4 and HO-1/NADPH signaling pathways

Hexavalent chromium salt, like potassium dichromate (PD), is chromium's most precarious valence state in industrial wastes. Recently, there has been increasing interest in β-sitosterol (BSS), a bioactive phytosterol, as a dietary supplement. BSS is recommended in treating cardiovascular disorders due to its antioxidant effect. Trimetazidine (TMZ) was used traditionally for cardioprotection. Through the administration of BSS and TMZ, the cardiotoxic effects of PD were to be countered in this study, in addition to examining the precise mechanism of PD-induced cardiotoxicity. Thirty male albino rats were divided into five groups; the control group: administered normal saline daily (3 mL/kg); the PD group: administered normal saline daily (3 mL/kg); BSS group: administered BSS daily (20 mg/kg); TMZ group: administered TMZ daily (15 mg/kg); and the BSS + TMZ group: administered both BSS (20 mg/kg) and TMZ (15 mg/kg) daily. All experimental groups, except the control, received on the 19th day a single dose of PD (30 mg/kg/day, S.C.). Normal saline, BSS, and TMZ were received daily for 21 consecutive days p.o. The exposure to PD promoted different oxidative stresses, pro-inflammatory, and cardiotoxicity biomarkers. BSS or TMZ succeeded solely in reducing these deleterious effects; however, their combination notably returned measured biomarkers close to normal values. The histopathological investigations have supported the biochemical findings. The combination of BSS and TMZ protects against PD cardiotoxicity in rats by reducing oxidative stress and apoptotic and inflammatory biomarkers. It may be promising for alleviating and protecting against PD-induced cardiotoxicity in people at an early stage; however, these findings need further clinical studies to be confirmed. HIGHLIGHTS: • Potassium dichromate induces cardiotoxicity in rats through the upregulation of oxidative stress, proinflammatory, and apoptotic pathways biomarkers. • β-Sitosterol possesses a possible cardioprotective effect by modulating several signaling pathways. • Trimetazidine, the antianginal agent, has a potential cardioprotective impact on PD-intoxicated rat model. • The combination of β-Sitosterol and trimetazidine was the best in modulating different pathways involved in PD cardiotoxicity in rats via the interplay between NF-κB/AMPK/mTOR/TLR4 and HO-1/NADPH signaling pathways.

Signaling Pathways and Genes Associated with Hexavalent Chromium-Induced Hepatotoxicity

Exposure to hexavalent chromium [Cr(VI)] causes human and animal hepatotoxicity. However, it is unclear how Cr(VI) induces hepatotoxicity, nor is it clear which pathways and genes may be involved. This study aimed to identify the key molecular pathways and genes engaged in Cr(VI)-induced hepatotoxicity. Publicly available microarray GSE19662 was downloaded from the Gene Expression Omnibus database. GSE19662 consists of primary rat hepatocyte (PRH) groups treated with or without 0.10 ppm potassium dichromate (PD), with three samples per group. Compared to the control group, a total of 400 differentially expressed genes were obtained. Specially 262 and 138 genes were up- and downregulated in PD-treated PRHs, respectively. Gene ontology (GO) enrichment indicated that those DEGs were primarily engaged in many biological processes, including androgen biosynthetic process, the positive regulation of cell death, the response to activity, the toxic substance and hepatocyte growth factor stimulus, and others. Kyoto Encyclopedia of Genes and Genomes (KEGG) suggested that the DEGs are fundamentally enriched in hepatocellular carcinoma (HCC), hepatitis B, p53, PI3K-Akt, MAPK, AMPK, metabolic pathways, estrogen, cGMP-PKG, metabolic pathways, etc. Moreover, many genes, including UBE2C, TOP2A, PRC1, CENPF, and MKI67, might contribute to Cr(VI)-induced hepatotoxicity. Taken together, this study enhances our understanding of the regulation, prevention, and treatment strategies of Cr(VI)-induced hepatotoxicity.

The role of mitochondrial dynamics imbalance in hexavalent chromium-induced apoptosis and autophagy in rat testis

Hexavalent chromium (Cr(VI)) is a ubiquitous environmental pollutant that can cause reproductive toxicity. However, the exact mechanism of Cr(VI)-induced testis toxicity remains largely elusive. This study aims to explore the possible molecular mechanism of Cr(VI)-provoked testicular toxicity. Male Wistar rats were intraperitoneally injected with 0, 2, 4, or 6 mg/kg body weight/day of potassium dichromate (K₂Cr₂O₇), respectively, for 5 weeks. The results revealed that Cr(VI)-treated rat testis presented varying degrees of damage in a dose-dependent manner. Concretely, Cr(VI) administration suppressed Sirtuin 1/Peroxisome proliferator-activated receptor-γ coactivator-1α pathway and led to mitochondrial dynamics disorder, along with the elevation of mitochondrial division and the repression of mitochondrial fusion. Meanwhile, the downstream effector of Sirt1, nuclear factor-erythroid-2-related factor 2 (Nrf2), was downregulated, and correspondingly exacerbated oxidative stress. Mitochondrial dynamics disorder and Nrf2 inhibition collectively contribute to abnormal mitochondrial dynamics in testis, which further promotes apoptosis and autophagy, evidenced by dose-dependently increasing the protein levels and gene expressions of apoptosis-related (including Bcl-2-associated X protein, cytochrome c, and cleaved-caspase 3) and autophagy-related (Beclin-1, ATG4B, and ATG5). Collectively, our results demonstrate that Cr(VI) exposure induced testis apoptosis and autophagy by disrupting the balance of mitochondrial dynamics and the oxidation-reduction process in rats.

Two-week repair alleviates hexavalent chromium-induced hepatotoxicity, hepatic metabolic and gut microbial changes: A dynamic inhalation exposure model in male mice

Hexavalent chromium [Cr(VI)] has been identified as a "Group I human carcinogen" with multisystem and multiorgan toxicity. A dynamic inhalation exposure model in male mice, coupled with the hepatic metabolome and gut microbiome, was used to explore hepatotoxicity, and hepatic metabolic and gut microbial changes under the exposure scenarios in the workspace and general environment. The present study set up an exposure group (EXP) that inhaled 150 μg Cr/m³ for 13 weeks, a control group (CONT) that inhaled purified air, as well as a two-week repair group (REXP) after 13 weeks of exposure and the corresponding control group (RCONT). Cr(VI) induced elevation of hepatic Cr accumulation, the ratio of ALT and AST, and folate in serum. Inflammatory infiltration in the liver and abnormal mitochondria in hepatocytes were also induced by Cr(VI). Glutathione, ascorbate, folic acid, pantetheine, 3'-dephospho-CoA and citraconic acid were the key metabolites affected by Cr(VI) that were associated with significant pathways such as pantothenate and CoA biosynthesis, hypoxia-inducible factor-1 signaling pathway, antifolate resistance, alpha-linolenic acid metabolism and one carbon pool by folate. g_Allobaculum was identified as a sensitive biomarker of Cr(VI) exposure because g_Allobaculum decreased under Cr(VI) exposure but increased after repair. The gut microbiota might be involved in the compensation of hepatotoxicity by increasing short-chain fatty acid-producing bacteria, including g_Lachnospiraceae_NK4A136_group, g_Blautia, and f_Muribaculaceae. After the two-week repair, the differential metabolites between the exposed and control groups were reduced from 73 to 29, and the KEGG enrichment pathways and differential microbiota also decreased. The mechanism for repair was associated with reversion of lipid peroxidation and energy metabolism, as well as activation of protective metabolic pathways, such as the AMPK signaling pathway, longevity regulating pathway, and oxidative phosphorylation. These findings might have theoretical and practical implications for better health risk assessment and management.

Seaweed polysaccharide relieves hexavalent chromium-induced gut microbial homeostasis

Heavy metals released in the environment pose a huge threat to soil and water quality, food safety and public health. Additionally, humans and other mammals may also be directly exposed to heavy metals or exposed to heavy metals through the food chain, which seriously threatens the health of animals and humans. Chromium, especially hexavalent chromium [Cr (VI)], as a common heavy metal, has been shown to cause serious environmental pollution as well as intestinal damage. Thus, increasing research is devoted to finding drugs to mitigate the negative health effects of hexavalent chromium exposure. Seaweed polysaccharides have been demonstrated to have many pharmacological effects, but whether it can alleviate gut microbial dysbiosis caused by hexavalent chromium exposure has not been well characterized. Here, we hypothesized that seaweed polysaccharides could alleviate hexavalent chromium exposure-induced poor health in mice. Mice in Cr and seaweed polysaccharide treatment group was compulsively receive K2Cr2O7. At the end of the experiment, all mice were euthanized, and colon contents were collected for DNA sequencing analysis. Results showed that seaweed polysaccharide administration can restore the gut microbial dysbiosis and the reduction of gut microbial diversity caused by hexavalent chromium exposure in mice. Hexavalent chromium exposure also caused significant changes in the gut microbial composition of mice, including an increase in some pathogenic bacteria and a decrease in beneficial bacteria. However, seaweed polysaccharides administration could ameliorate the composition of gut microbiota. In conclusion, this study showed that seaweed polysaccharides can restore the negative effects of hexavalent chromium exposure in mice, including gut microbial dysbiosis. Meanwhile, this research also lays the foundation for the application of seaweed polysaccharides.

Silicon oxide nanoparticles alleviate chromium toxicity in wheat (Triticum aestivum L.)

Increasing chromium (Cr) contamination in agricultural soils is a threat to crop yields and quality. Recently, nano-enabled strategies have been emerging with a great potential towards improving crop production and reclaiming the heavy metal contaminated soils. This study aimed to elucidate the potential of silicon oxide nanoparticles (SiONPs) on optimizing wheat growth and yield against Cr stress-induced phytotoxicity. Spherical crystalline SiONPs with the diameter in the range of 15-24 nm were applied at a dose of 250 mg kg^-1 soil for pot experiments planted with wheat seedlings, with or without Cr contaminations. The pot experiment results showed that SiONPs amendments significantly improved the plant length (26.8%), fresh (28.5%) and dry weight (30.4%) as compared with the control treatment. In addition, SiONPs also enhanced photosynthetic activity, antioxidant enzyme contents (CAT, APX, SOD and POD content) and reduced the reactive oxygen species (ROS) in wheat plants under Cr stress condition. The alleviation of Cr toxicity was deemed to be associated with the reduced Cr uptake into the roots (-39.6%) and shoots (-35.7%). The ultrastructural analyses revealed that the application of SiONPs in Cr contaminated soils maintained the normal cellular structure of the wheat plant, as compared with those of controls without SiONPs. These results provide the first evidence showing the great potential of SiONPs application towards alleviating the Cr stress for optimized wheat growth and yield in Cr contaminated soils.

Gypenosides counteract hepatic steatosis and intestinal barrier injury in rats with metabolic associated fatty liver disease by modulating the adenosine monophosphate activated protein kinase and Toll-like receptor 4/nuclear factor kappa B pathways

CONTEXT

Non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease, can develop into metabolic associated fatty liver disease (MAFLD). Gypenosides (GP), the main phytochemical component of Gynostemma pentaphylla (Thunb.) Makino (Cucurbitaceae), have been applied for treatment of metabolic diseases.

OBJECTIVE

We investigate how GP modulate MAFLD-related hepatic steatosis and intestinal barrier injury.

MATERIALS AND METHODS

In cell experiments, Caco-2 cells were treated with GP (150 or 200 μmol/L, 24 h), following lipopolysaccharide (LPS) exposure (10 μg/mL, 24 h) to mimic MAFLD in vitro. In in vivo experiments, control, model and model + GP groups were set. High fructose diet/high fat (HFD/HF)-fed (12 weeks) MAFLD rats received GP treatment (300 mg/kg, 6 weeks), followed by intra-peritoneal glucose tolerance test and histopathological examination of rat liver and intestinal mucosa using haematoxylin-eosin staining.

RESULTS

GP at 200 μM significantly reversed LPS-induced decreases in transepithelial electrical resistance (TER) value (25%), protein expression of occludin (two fold) and ZO-1 (four fold), and the ratio of p-AMPK to AMPK (five fold), while partially repressing LPS-induced leakage of FD4 (50%) and LPS-induced increases in the Toll-like receptor 4 (TLR4) level (50%) and the ratio of p-p65 to p65 (55%). Compared with the model rats, rats with GP treatment presented a reduction in gain of weight and glucose tolerance. In addition, GP alleviated HFD/HF-induced histopathological abnormalities in rat liver and intestinal mucosa.

CONCLUSIONS

GP attenuates hepatic steatosis and intestinal barrier injury in MAFLD rats via the AMPK and TLR4/nuclear factor kappa B (NF-κB) pathways, providing a potential treatment for MAFLD patients.

Perinatal exposure to glyphosate-based herbicides impairs progeny health and placental angiogenesis by disturbing mitochondrial function

Glyphosate-based herbicides (GBHs) are the most widely used pesticide worldwide and can provoke placental injury. However, whether and how GBHs damage angiogenesis in the placenta is not yet known. This work evaluated the safety of glyphosate on pregnant sows based on the limit level by governments and investigated the effects and mechanism of Low-GBHs (20 mg/kg) and High-GBHs (100 mg/kg) exposure on placental angiogenesis. Results showed that gestational exposure to GBHs decreased placental vessel density and cell multiplication by interfering with the expression of VEGFA, PLGF, VEGFr2 and Hand2 (indicators of angiogenesis), which may be in relation to oxidative stress-induced disorders of mitochondrial fission and fusion as well as the impaired function of the mitochondrial respiratory chain. Additionally, GBHs destroyed barrier function and nutrient transport in the placenta, and was accompanied by jejunum oxidative stress in newborn piglets. However, GBHs exposure had no significant differences on sow reproductive performance. As a natural antioxidant, betaine treatment protected placenta and newborn piglets against GBHs-induced damage. In conclusion, GBHs impaired placental angiogenesis and function and further damaged the health of postnatal progeny, these effects may be linked to mitochondrial dysfunction. Betaine treatment following glyphosate exposure provided modest relief.

Selenium regulates Nrf2 signaling to prevent hepatotoxicity induced by hexavalent chromium in broilers

Hexavalent chromium (Cr(Ⅵ)) is considered to be a common environmental pollutant, which widely exists in industrial effluents and wastes and then potentially noxious effects to the health of the poultry. Studies have reported that selenium (Se), which is one of the essential trace elements of the poultry and participates in the oxidative metabolism, can alleviate Cr(Ⅵ)-induced organ damage by inhibiting oxidative stress, but its specific molecular mechanism remains unclear. Herein, animal models of Cr(Ⅵ)- and Se-exposure were constructed using broilers to investigate the antagonistic mechanism of Se to Cr(Ⅵ)-induced hepatotoxicity. In this experiment, the four groups of broiler models were used as the research objects: control, Se, Se plus Cr, and Cr groups. Histopathology and ultrastructure liver changes were observed. Liver-somatic index, serum biochemistry, oxidative stress, Nrf2 pathway related factors, and autophagy-related genes were also determined. Overall, Se was found to ameliorate the disorganized structure, hepatic insufficiency, and oxidative damage caused by Cr(Ⅵ) exposure. Electron microscopy analysis further showed that the number of autophagosomes was obviously decreased after Se treatment compared to Cr group. Furthermore, gene and protein expression analyses illustrated that the levels of Nrf2, glutathione peroxidase 1 (GPx-1), NAD(P)H: quinone oxidoreductase 1 (NQO1), and mechanistic target of rapamycin (mTOR) in the Se&Cr group was upregulated, along with decreased expression of Beclin 1, ATG5 and LC3 compared to the Cr group. These suggest that Se can repair the oxidative lesion and autophagy induced by Cr(Ⅵ) exposure in broiler livers by upregulating the Nrf2 signaling pathway.

A comprehensive review on human health effects of chromium: insights on induced toxicity

The growing use of heavy metals in most industrial activities has led to it being considered as the most important environmental pollutant that may cause harm and toxicity to animals and humans. Chromium has been found in the environment in different oxidation states such as Cr⁰, Cr(III), and Cr(VI) and is released from a variety of anthropogenic and natural activities. At among, trivalent and hexavalent chromium are the most stable forms. Considerably, Cr(VI) is frequently more toxic than Cr(III) because of its particular solubility and high mobility. Chronic exposure and bioaccumulation of chromium, as a heavy metal, can cause toxicity and numerous pathophysiological defects, including allergic reactions, anemia, burns, and sores especially in the stomach and small intestine, damage to sperm along with the male reproductive system, and affect various biological systems. Chromium pollution can have severe consequences for water and the soil environment. This article reviews the toxicological effects of Cr(VI) and Cr(III) and their mechanisms of toxicity and carcinogenicity.

Battery wastewater induces nephrotoxicity via disordering the mitochondrial dynamics

The rapid development of new energy battery enterprises manifolds the obsolete and scrapped batteries which are considered serious concern for the environment and ecology. Increasing trend of recycling batteries waste is public hazard throughout the world. The batteries wastes affect the various body systems but exact toxicological mechanism of battery wastewater is still unexplored. The present study was designed to observe the toxicological effects of batteries wastes on kidney functional dynamics. In this experiment, a total of 20 male mice were randomly divided into two groups including control and treatment (battery wastewater) group. The control group was provided the normal saline while the battery wastewater group were provided battery waste-water for a period of 21 days. The isolated kidneys were processed for histopathological analysis, biochemical assays, mRNA and protein estimation. The results showed that battery wastewater provision increased the mitochondrial division-related genes and proteins (Drp1, MFF, Fis1) and decreased the expression level of fusion-related nuclear proteins (MFN1, MFN2, OPA1) in kidneys. Moreover, the battery wastewater exposure significantly up-regulated the autophagy (PINK, Parkin, mTOR, ATG5, LC3-b, p62) and apoptosis (Bax, Cytc, APAF1, P53, Caspase3, Caspase8) related mRNA and proteins levels in kidneys. However, down-regulation of mRNA and proteins levels of Bcl2 and Beclin1 were also observed in kidneys after batteries wastes exposure. In conclusion, it is evident that the battery wastewater leads to renal apoptosis and autophagy by disrupting the mitochondrial dynamics in mice kidneys.

Deltamethrin induces apoptosis in cerebrum neurons of quail via promoting endoplasmic reticulum stress and mitochondrial dysfunction

Deltamethrin (DLM) is a widely used and highly effective insecticide. DLM exposure is harmful to animal and human. Quail, as a bird model, has been widely used in the field of toxicology. However, there is little information available in the literature about quail cerebrum damage caused by DLM. Here, we investigated the effect of DLM on quail cerebrum neurons. Four groups of healthy quails were assigned (10 quails in each group), respectively given 0, 15, 30, and 45 mg/kg DLM by gavage for 12 weeks. Through the measurements of quail cerebrum, it was found that DLM exposure induced obvious histological changes, oxidative stress, and neurons apoptosis. To further explore the possible molecular mechanisms, we performed real-time quantitative PCR to detect the expression of endoplasmic reticulum (ER) stress-related mRNA such as glucose regulated protein 78 kD, activating transcription factor 6, inositol requiring enzyme, and protein kinase RNA (PKR)-like ER kinase. In addition, we detected ATP content in quail cerebrum to evaluate the functional status of mitochondria. The study showed that DLM exposure significantly increased the expression of ER stress-related mRNA and decreased ATP content in quail cerebrum tissues. These results suggest that chronic exposure to DLM induces apoptosis of quail cerebrum neurons via promoting ER stress and mitochondrial dysfunction. Furthermore, our results provide a novel explanation for DLM-induced apoptosis of avian cerebrum neurons.

Exposure to Bisphenol A Caused Hepatoxicity and Intestinal Flora Disorder in Rats

Bisphenol A (BPA) is a globally utilized industrial chemical and is commonly used as a monomer of polycarbonate plastics and epoxy resins. Recent research reveals that BPA could cause potential adverse biological effects and liver dysfunction. However, the underlying mechanisms of BPA-induced hepatoxicity and gut dysbiosis remain unclear and deserve further study. In this study, male Sprague Dawley rats were exposed to different doses (0, 30, 90, and 270 mg/kg bw) of BPA by gavage for 30 days. The results showed that the high dose of BPA decreased superoxide dismutase (SOD), glutathione (GSH), and increased malondialdehyde (MDA) levels. Moreover, a high dose of BPA caused a significant increase in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C), while high-density lipoprotein cholesterol (HDL-C) was significantly decreased in BPA-treated rats. The gene expression of PGC-1α and Nrf1 were decreased in the liver of high doses of BPA-administrated rats, as well as the protein levels of SIRT1, PGC-1α, Nrf2, and TFAM. However, the protein expression of IL-1β was significantly increased in BPA-treated rats. In addition, BPA weakened the mitochondrial function of hepatocytes and promoted cell apoptosis in the liver by up-regulating the protein levels of Bax, cleaved-Caspase3, and cleaved-PARP1 while down-regulating the Bcl-2 in the liver. More importantly, a high dose of BPA caused a dramatic change in microbiota structure, as characterized at the genus level by increasing the ratio of Firmicutes to Bacteroidetes (F/B), and the relative abundance of Proteobacteria in feces, while decreasing the relative abundance of Prevotella_9 and Ruminococcaceae_UCG-014, which is positively correlated with the content of short-chain fatty acids (SCFAs). In summary, our data indicated that BPA exposure caused hepatoxicity through apoptosis and the SIRT1/PGC-1α pathway. BPA-induced intestinal flora and SCFA changes may be associated with hepatic damage. The results of this study provide a new sight for the understanding of BPA-induced hepatoxicity.

San-Huang-Chai-Zhu Formula Ameliorates Liver Injury in Intrahepatic Cholestasis through Suppressing SIRT1/PGC-1α-Regulated Mitochondrial Oxidative Stress

Background

Chinese herbal formulae possess promising applications in treating intrahepatic cholestasis.

Objective

Our study aims to explore the protective effect of the San-Huang-Chai-Zhu formula (SHCZF) on liver injury in intrahepatic cholestasis (IC) and investigate the underlying mechanism related to mitochondrial oxidative stress.

Methods

An IC rat model was established by α-naphthyl isothiocyanate induction. Hepatic histomorphology was observed through hematoxylin and eosin staining. Levels of biochemical indexes of hepatic function and oxidative stress were determined by an enzyme-linked immunosorbent assay. Cell apoptosis in liver tissues was detected by the TUNEL assay. The mRNA expression of mtDNA, SIRT1, and PGC-1α was measured by qRT-PCR, and the protein expression of Bax, Bcl-2, caspase-3, SIRT1, and PGC-1α was determined by Western blotting.

Results

SHCZF treatment attenuated liver injury in IC. Levels of hepatic function parameters were decreased after SHCZF administration. In addition, the decreased level of malondialdehyde (MDA) and the increased levels of superoxide dismutase (SOD), glutathione (GSH), and adenosine triphosphate (ATP) in hepatic mitochondria confirmed that SHCZF could attenuate oxidative stress in IC. SHCZF treatment also reduced the apoptosis in the liver tissues of IC rats. Furthermore, SHCZF administration upregulated the expression of mtDNA, SIRT1, and PGC-1α in IC.

Conclusions

SHCZF exerts a protective effect on liver injury in IC via alleviating SIRT1/PGC-1α-regulated mitochondrial oxidative stress.

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

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

New insights into the reverse of chromium-induced reprotoxicity of pregnant mice by melatonin

Hexavalent chromium Cr(VI) is a well-known environmental toxic metal that causes reprotoxicity in pregnant females. There are currently no appropriate interventions or treatments for Cr(VI) exposure during pregnancy. Herein, the protective effect of melatonin (MLT) against Cr(VI)-induced reprotoxicity is investigated by administrating MLT to pregnant mice exposed to Cr(VI). The results indicate that MLT effectively alleviates Cr(VI)-induced adverse pregnancy outcomes, restoring the decreased fetal weight and increased fetal resorption and malformation caused by Cr(VI) exposure to normal levels. MLT reduces the negative effects of Cr(VI) on follicular atresia and the development of primordial follicle in the maternal ovarian, thereby mitigating the decline in the reserve of primordial follicles. MLT alleviates Cr(VI)-induced oxidative stress, hence reducing the excessive accumulation of malondialdehyde in the maternal ovary. MLT inhibits Cr(VI)-induced apoptosis of ovarian granulosa cells and the expression of cleaved caspase-3 in the ovary. MLT reduces the increase in serum follicle-stimulating hormone caused by Cr(VI) exposure, while elevating anti-Mullerian hormone levels. We demonstrate that MLT reverses Cr(VI)-induced reprotoxicity in pregnant mice, opening up a new avenue for treating reproductive defects caused by environmental stress.

Harmful Effects of Inorganic Mercury Exposure on Kidney Cells: Mitochondrial Dynamics Disorder and Excessive Oxidative Stress

Mercury is widely used in industry and has caused global environmental pollution. Inorganic mercury accumulates in the body causes damage to many organs, and the kidney is the most susceptible to the toxic effects of mercury. However, the underlying specific molecular mechanism of renal injury induced by inorganic mercury remains unclear at the cellular level. Therefore, in order to understand its molecular mechanism, we used in vitro method. We established experimental models by treating human embryonic kidney epithelial cell line (HEK-293 T) cells with HgCl₂ (0, 1.25, 5, and 20 µmol/L). We found that HgCl₂ can lead to a decrease in cell viability and oxidative stress of HEK-293 T, which may be mediated by upregulation mitochondrial fission. In addition, HgCl₂ exposure resulted in the mitochondrial disorder of HEK-293 T cells, which was mediated by downregulating the expression of silent information regulator two ortholog 1 (Sirt1)/peroxisome proliferator-activated receptor coactivator-1α (PGC-1α) signaling pathway. In summary, our results suggest that HgCl₂ induces HEK-293 T cell toxicity through promoting Sirt1/PGC-1α axis-mediated mitochondrial dynamics disorder and oxidative stress. Sirt1/PGC-1α may be an appealing pharmaceutical target curing HgCl₂-induced kidney injury.

Activation of the GPX4/TLR4 Signaling Pathway Participates in the Alleviation of Selenium Yeast on Deltamethrin-Provoked Cerebrum Injury in Quails

Deltamethrin (DLM) is a member of pyrethroid pesticide widely applied for agriculture and aquaculture, and its residue in the environment seriously threatens the bio-safety. The cerebrum might be vulnerable to pesticide-triggered oxidative stress. However, there is no specific antidote for treating DLM-triggered cerebral injury. Selenium (Se) is an essential trace element functionally forming selenoprotein glutathione peroxidase (GPX) in antioxidant defense. Se yeast (SY) is a common and effective organic form of Se supplement with high selenomethionine content. Accordingly, this study focused on investigating the therapeutic potential of SY on DLM-induced cerebral injury in quails after chronically exposing to DLM and exploring the underlying mechanisms. Quails were treated with/without SY (0.4 mg kg^-1 SY added in standard diet) in the presence/absence of DLM (45 mg kg^-1 body weight intragastrically) for 12 weeks. The results showed SY supplementation ameliorated DLM-induced cerebral toxicity. Concretely, SY elevated the content of Se and increased GPX4 level in DLM-treated quail cerebrum. Furthermore, SY enhanced antioxidant defense system by upregulating nuclear factor-erythroid-2-related factor 2 (Nrf2) associated members. Inversely, SY diminished the changes of apoptosis- and inflammation-associated proteins and genes including toll-like receptor 4 (TLR4). Collectively, our results suggest that dietary SY protects against DLM-induced cerebral toxicity in quails via positively regulating the GPX4/TLR4 signaling pathway. GPX4 may be a potential therapeutic target for insecticide-induced biotoxicity.

Regulation of Cr(VI)-Induced Premature Senescence in L02 Hepatocytes by ROS-Ca2+-NF-κB Signaling

Stress-induced premature senescence may be involved in the pathogeneses of acute liver injury. Hexavalent chromium [Cr(VI)], a common environmental pollutant related to liver injury, likely leads to premature senescence in L02 hepatocytes. However, the underlying mechanisms regarding hepatocyte premature senility in Cr(VI) exposure remain poorly understood. In this study, we found that chronic exposure of L02 hepatocytes to Cr(VI) led to premature senescence characterized by increased β-galactosidase activity, senescence-associated heterochromatin foci, G1 phase arrest, and decreased cell proliferation. Additionally, Cr(VI)-induced senescent L02 hepatocytes showed upregulated inflammation-related factors, such as IL-6 and fibroblast growth factor 23 (FGF23), which also exhibited reactive oxygen species (ROS) accumulation derived from mitochondria accompanied with increased concentration of intracellular calcium ions (Ca²⁺) and activity of nuclear factor kappa B (NF-κB). Of note is that ROS inhibition by N-acetyl-Lcysteine pretreatment not only alleviated Cr(VI)-induced premature senescence but also reduced the elevated intracellular Ca²⁺, activated NF-κB, and secretion of IL-6/FGF23. Intriguingly, the toxic effect of Cr(VI) upon premature senescence of L02 hepatocytes and increased levels of IL-6/FGF23 could be partially reversed by the intracellular Ca²⁺ chelator BAPTA-AM pretreatment. Furthermore, by utilizing the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC), we confirmed that NF-κB mediated IL-6/FGF23 to regulate the Cr(VI)-induced L02 hepatocyte premature senescence, whilst the concentration of intracellular Ca²⁺ was not influenced by PDTC. To the best of our knowledge, our data reports for the first time the role of ROS-Ca²⁺-NF-κB signaling pathway in Cr(VI)-induced premature senescence. Our results collectively shed light on further exploration of innovative intervention strategies and treatment targeting Cr(VI)-induced chronic liver damage related to premature senescence.

Arsenic causes mitochondrial biogenesis obstacles by inhibiting the AMPK/PGC-1α signaling pathway and also induces apoptosis and dysregulated mitophagy in the duck liver

Arsenic is a dangerous metalloid-material which is known to cause liver injury in many animals and humans. However, little is known about the underlying mechanism of arsenic-induced hepatotoxicity in poultry. This study was executed to systematically investigate the potential role of mitochondrial biogenesis, mitophagy and apoptosis in duck hepatotoxicity caused by arsenic. Results showed that the body weight and liver coefficient of duck had distinct changed after arsenic-exposure, and the arsenic content in serum and liver also increased significantly in a dose-dependent manner. Meanwhile, histopathological examination and metabolomics results showed that arsenic-exposure caused severe steatosis and metabolism disorder in liver tissues. Furthermore, arsenic-exposure significantly inhibited AMPK/PGC-1α-mediated mitochondrial biogenesis, determined by the ultrastructure observation and down-regulation of p-AMPKα/AMPKα, PGC-1α, NRF1, NRF2, TFAM, TFB1M, TFB2M and COX-Ⅳ expression levels. Besides, arsenic-treatment obviously increased the levels of mitophagy (PINK1, Parkin, LC3, P62) and pro-apoptotic (Caspase-3, Caspase-9, Cleaved Caspase-3, Cytc, Bax, P53) indexes, and simultaneously resulted in reductions in anti-apoptosis index (Bcl-2). Overall, our findings provided evidences that arsenic-induced duck hepatotoxicity may be caused by a combination of impaired mitochondrial biosynthesis, mitophagy, and mitochondrial-dependent apoptosis. To our knowledge, this is the first report to systematically investigate the potential mechanism of arsenic-induced hepatotoxicity in poultry.

Effect of inorganic mercury exposure on reproductive system of male mice: Immunosuppression and fibrosis in testis

Mercury as a toxic heavy metal will accumulate in the body and induce various diseases through the food chain. However, it is unknown that the detailed mechanism of reproductive disorder induced by inorganic mercury in male mice to date. This study investigated the toxicological effect of mercuric chloride (HgCl₂ ) exposure on reproductive system in male mice. Male Kunming mice received normal saline daily or HgCl₂ (3 mg/kg bodyweight) by intraperitoneal injection for a week. The reproductive function was evaluated, and the HgCl₂ exposure induced the decline of sperm quality, pregnancy rate, mean litter size, and survival rate. Notably, we firstly found the HgCl₂ -induced immunosuppression and fibrosis in mice testis according to the results of RNA sequencing. Collectively, these findings demonstrate that HgCl₂ exposure disrupts the reproductive system and induces testicular immunosuppression and fibrosis via inhibition of the CD74 signaling pathway in male mice.

Gastroprotective effect and mechanisms of Chinese sumac fruits (Rhus chinensis Mill.) on ethanol-induced gastric ulcers in mice

This paper aimed to study the effect of the phenol-rich fraction from Chinese sumac fruits on ethanol-induced gastric ulcers in mice and to further elucidate the potential mechanisms. The results showed that the phenol-rich fraction of the fruits significantly decreased the ulcer index, restored the levels of prostaglandin E-2, heat shock protein 70, glutathione and superoxide dismutase, and reduced the malondialdehyde content. Further analyses revealed that the fraction significantly alleviated the gastric oxidative stress by upregulating the Nrf2 protein pathway to increase the HO-1 and NQO1 expression levels, suppressed the inflammation by reducing the expression levels of p-NF-κB and p-IκBα and inhibited the secretion of tumor necrosis factor-α, interleukin-1β, and interleukin-6. In addition, the fraction remarkably prevented gastric mucous cell apoptosis by upregulating Bcl-2 and downregulating Bax and cleaved caspase3. This experiment clarified for the first time that the phenol-rich fraction from Chinese sumac fruits can prevent ethanol-induced gastric ulcers in mice by inhibiting the oxidative stress, inflammatory response and cell apoptosis. The results obtained from the current work indicated that the phenol-rich fraction from Chinese sumac fruits could be applied as a kind of natural resource for producing new functional foods to prevent and/or improve gastric ulcers induced by ethanol.

Ganoderic acid improves 5-fluorouracil-induced cognitive dysfunction in mice

5-Fluorouracil (5-FU) is a chemotherapeutic drug with a good anti-cancer effect on various types of cancers, such as colorectal cancer and breast cancer. However, previous studies have found that 5-FU could induce cognitive deficit in clinics. As ganoderic acid, isolated from Ganoderma lucidum, has a protective effect on neurons, this study investigated the effects of ganoderic acid (GA) against 5-FU-induced cognitive dysfunction with a series of behavioral tests and related indicators. Experimental results showed that GA significantly prevented the reduction of spatial and non-spatial memory in 5-FU-treated mice. In addition, GA not only ameliorated the damage to hippocampal neurons and mitochondrial structure, but also significantly improved abnormal protein expression of mitochondrial biogenesis related marker PGC-1α, and mitochondrial dynamics related markers MFN2, DRP1 and FIS1 in the hippocampi of 5-FU-treated mice. Moreover, GA could up-regulate the expression of neuronal survival and growth-related proteins, such as BDNF, p-ERK, p-CREB, p-Akt, p-GSK3β, Nrf2, p-mTOR, and p-S6, in the hippocampi of 5-FU-treated mice. These results suggest that GA could prevent cognitive dysfunction in mice treated with 5-FU via preventing mitochondrial impairment and enhancing neuronal survival and growth, which provide evidence for GA as a promising adjunctive therapy for chemotherapy related cognitive impairment in clinics.

Nano-selenium alleviating the lipid metabolism disorder of LMH cells induced by potassium dichromate via down-regulating ACACA and FASN

Chromium (Cr) VI is a common environmental contaminant highly toxic to livers. To explore the protective effect of nano-selenium (NANO-Se) on broiler liver damage caused by Cr (VI), this experiment was conducted with chicken hepatocellular carcinoma cell line (LMH) as the research object, using potassium dichromate (PDC) and NANO-Se gel for culturing cells. The results indicated that: (1) in the PDC-exposure group, LMH cells being treated with 20 μmol/L PDC for 24 h, IC50 (median inhibition concentration) = 23.427 could significantly reduce cell activity (p < 0.01) which decreased over time. PDC markedly increased the concentration of triglycerides (TG) and low-density lipoprotein cholesterol (LDL-C) in LMH cells (p < 0.01), which increased over time. In addition, PDC could substantially augment the transcription and protein levels of acetyl-CoA carboxylases alpha (ACACA) and fatty acid synthase (FASN) in LMH cells (p < 0.01). (2) Compared with the PDC-exposure group, the addition of 8 μmol/L NANO-Se after 12 h of PDC treatment could significantly increase the cell viability (p < 0.01) but decreased over time; the levels of TG and LDL-C in LMH cells declined markedly (p < 0.01). In addition, the transcription and protein levels of ACACA and FASN in LMH cells were significantly reduced (p < 0.01). (3) The LMH cells were cultured in advance with 8 μmol/L NANO-Se for 12 h and then with PDC for 24 h. The obtained results were similar to the above. There were no obvious differences in TG and LDL-C levels (p > 0.05). However, significant differences were found in the activity of LMH cells and the expression of genes related to lipid metabolism (p < 0.05).All these results suggest that the exposure to PDC promotes the increase of lipid synthesis in LMH cells and causes disorders in the lipid metabolism. Moreover, NANO-Se can partially attenuate the damage caused by PDC through down-regulating of the lipid metabolism-related genes (ACACA and FASN) in LMH cells.

Hexavalent chromium inhibits the formation of neutrophil extracellular traps and promotes the apoptosis of neutrophils via AMPK signaling pathway

As the most common heavy metal pollutant, hexavalent chromium [Cr(VI)] has caused serious environmental pollution and health damage. Although the toxic effect of Cr(VI) has been widely studied, and oxidative stress has been confirmed to be the main mechanism of its cytotoxicity, the toxicity of Cr(VI) to human immune system remains to be elucidated. Neutrophil extracellular traps (NETs) participate in the innate immune response, and the release of NETs is considered to be the most important part of the extracellular killing mechanism. We demonstrated in this study that Cr(VI) inhibited the formation of NETs in rat peripheral blood and induced neutrophils apoptosis by inhibiting the AMP-activated protein kinase (AMPK) signaling pathway. Cr(VI)-induced inhibition of NETs was accompanied by down-regulated myeloperoxidase (MPO)/Histones-3 (H3) protein expressions and decreased NETs-associated intracellular and extracellular DNA levels in the neutrophils. Metformin (Met), as an AMPK activator, triggered autophagy and thus alleviated the inhibitory effect of Cr(VI) on NETs. At the same time, Met can reduce the intracellular reactive oxygen species (ROS) level by activating the AMPK/nuclear factor erythroid-2 related factor 2 (Nrf2) signaling pathway, thus alleviating Cr(VI)-induced neutrophils apoptosis. In conclusion, this study elucidated the mechanism of Cr(VI)-induced neutrophils toxicity and the role of AMPK as a key regulatory signal, which could provide valuable experimental basis for the prevention and treatment of related diseases in Cr(VI)-exposed populations.

Toxicological effects of deltamethrin on quail cerebrum: Weakened antioxidant defense and enhanced apoptosis

Deltamethrin is the most common type II synthetic pyrethroid insecticide, and has posed widespread residues to environment. However, whether deltamethrin has potential toxic effects on quail cerebrum remains greatly obscure. Accordingly, we investigated the impact of chronic exposure to deltamethrin on oxidative stress and apoptosis in quail cerebrum. Quails upon 12-week exposure of deltamethrin (0, 15, 30, or 45 mg/kg body weight intragastric administration) were used as a cerebrum injury model. The results showed that deltamethrin treatment led to cerebral injury dose-dependently through the weakened antioxidant defense by downregulating nuclear factor erythroid-2-related factor 2 (Nrf2) and its downstream proteins levels and mRNA expression. Furthermore, deltamethrin treatment induced apoptosis in cerebrum by decreasing B-cell lymphoma gene 2 (Bcl-2) level, as well as increasing Jun N-terminal kinase3, caspase-3, and Bcl-2-associated X protein levels. Simultaneously, toll-like receptor 4 (TLR4) downstream inflammation-related genes or proteins were significantly up-regulated by deltamethrin dose-dependently. Altogether, our study demonstrated that chronic exposure to deltamethrin induces inflammation and apoptosis in quail cerebrums by promoting oxidative stress linked to inhibition of the Nrf2/TLR4 signaling pathway. These results provide a novel knowledge on the chronic toxic effect of deltamethrin, and establish a theoretical foundation for the evaluation of pesticide-induced health risk.

The aggravation of allergic airway inflammation with dibutyl phthalate involved in Nrf2-mediated activation of the mast cells

Dibutyl phthalate (DBP)-an organic pollutant-is ubiquitous in the environment. DBP as an immune adjuvant is related to the development of multiple allergic diseases. However, the current research involving DBP-induced pulmonary toxicity remains poorly understood. Therefore, this research aimed to explore the adverse effect and potential mechanism of DBP exposure on the lungs in rats. In our study, ovalbumin was used to build a rat model of allergic airway inflammation to study any harmful effect of DBP exposure on lung tissues. Rats were treated by intragastric administration of DBP (500 mg kg^-1 or 750 mg kg^-1) and/or subcutaneous injection of SFN (4 mg kg^-1). The results of histopathological analysis, cell count, and myeloperoxidase showed that DBP promoted the inflammatory damage of lungs. In the lung tissues, the detection of terminal deoxynucleotidyl transferase dUNT nick end labeling and oxidative stress indices showed that DBP significantly increased the level of apoptosis and oxidative stress. Western blot analysis indicated that DBP raised the expression level of thymic stromal lymphopoietin and reduced the nuclear expression level of nuclear factor-erythroid-2-related factor 2 (Nrf2), which was further verified by quantitative real-time PCR. Meanwhile, DBP treatment markedly up-regulated the inflammatory cytokines such as IL-4 and IL-13, and rat mast cell protease-2, a marker secreted by mast cells (MCs). Conversely, sulforaphane, a Nrf2 inducer, ameliorated the pulmonary damage induced by DBP in the above. Altogether, our data provides a new insight into the impacts of the activation of MCs on the DBP-induced pulmonary toxicity as well as the safety evaluation of DBP.

Periplaneta americana extract ameliorates lipopolysaccharide-induced liver injury by improving mitochondrial dysfunction via the AMPK/PGC-1α signaling pathway

Periplaneta americana (PA) extract acts clinically as a therapeutic treatment in various diseases; it enhances liver function in mouse models and mitigates the pathological condition of liver fibrosis. The present study aimed to investigate the role and potential mechanisms underlying the action of the PA extract, xinmailong (XML), in lipopolysaccharide (LPS)-induced liver injury. Following the treatment of AML12 cells with LPS, the content of cytochrome c in the cytoplasm and mitochondria, and the level of ATP synthesis were detected using corresponding kits. The relative mRNA expression levels of nuclear respiratory factor 1 and transcription factor A, mitochondrial were investigated using reverse transcription-quantitative (RT-q)PCR analysis. The MTT assay was performed to detect the viability of AML12 cells following treatment with XML, in the absence or presence of LPS. Western blot analysis was performed to determine the expression levels of proteins in the AMP-activated protein kinase (AMPK)/proliferator-activated receptor γ coactivator-1α (PGC-1α) pathway. Following treatment with compound C, an inhibitor of AMPK, the expression levels of inflammatory cytokines were determined using ELISA and RT-qPCR analysis. The levels of oxidative stress-related markers were detected using corresponding kits following treatment with compound C. In addition, TUNEL staining was performed to detect the apoptosis of AML12 cells, and western blot analysis was performed to investigate the expression levels of apoptosis-related proteins. Mitochondrial dysfunction was induced by LPS in AML12 cells. LPS stimulation significantly downregulated the expression of proteins in the AMPK/PGC-1α pathway, which was reversed following treatment with XML. In addition, inflammation, oxidative stress and mitochondrial dysfunction induced by LPS were alleviated by XML in AML12 cells. However, the addition of compound C and XML to LPS-induced AML12 cells resulted in the aggravation of cell injury. Collectively, the results of the present study indicated that XML suppressed mitochondrial dysfunction induced by LPS by activating AMPK/PGC-1α signaling. Thus, the results of the present study may contribute to further understanding of the underlying mechanism via which XML alleviates liver injury.