Increased glutathione synthesis following Nrf2 activation by vanadyl sulfate in human chang liver cells

Protective Effects of Lycium ruthenicum Murray against Acute Alcoholic Liver Disease in Mice via the Nrf2/HO-1/NF-κB Signaling Pathway

Acute alcoholic liver disease (ALD) resulting from short-term heavy alcohol consumption has become a global health concern. Moreover, anthocyanins have attracted much attention for their ability to prevent oxidation and inflammation. The present work evaluates the protective effects of Lycium ruthenicum Murray (LRM) against ALD and explores the possible underlying mechanism involved. The total anthocyanin content in LRM was 43.64 ± 9.28 Pt g/100 g dry weight. Mice were orally administered 50, 125, or 375 mg LRM/kg body weight (BW) for 21 days. On days 18-21, mice were orally administered 15 mL of ethanol/kg BW. Markers of liver damage, oxidative stress, and inflammation were examined. Furthermore, the modulatory effect of LRM on Nrf2/HO-1/NF-κB pathway molecules was evaluated through quantitative reverse transcription polymerase chain reaction (RT‒qPCR) and immunohistochemistry analyses. The difference between the groups indicated that LRM improved liver histopathology and the liver index, decreased aspartate transaminase, alanine transaminase, malondialdehyde, reactive oxygen species, IL-6, TNF-α, and IL-1β expression, but elevated superoxide dismutase, catalase, and glutathione-s-transferase levels. Moreover, LRM upregulated Nrf2 and Ho-1 but downregulated Nf-κb and Tnf-α genes at the transcript level. In summary, LRM alleviated ethanol-induced ALD in mice by reducing oxidative damage and associated inflammatory responses. LRM protects against ALD by reducing damage factors and enhancing defense factors, especially via the Nrf2/HO-1/NF-κB pathway. Thus, LRM has application potential in ALD prophylaxis and treatment.

Polyoxidovanadates as a pharmacological option against brain aging

The world population is aging rapidly, and chronic diseases associated are cardiometabolic syndrome, cancer, and neurodegenerative diseases. Oxidative stress and inflammation are typical hallmarks in them. Polyoxidovanadates (POVs) have shown interesting pharmacological actions against chronic diseases. This work aimed to evaluate the POV effect on hippocampal neuroinflammation, redox balance, and recognition memory in the aging of rats. Rats 18 months old were administered a daily dose of sodium metavanadate (MV), decavanadate (DV), Metformin (Metf), or MetfDeca for two months. Results showed that short-term and long-term recognition memory improved by 28 % and 16 % (DV), 19 % and 20 % (Metf), and 21 % and 27 % (MetfDeca). In hippocampi, reactive oxygen species, IL-1β, and TNF-α, after DV, Metf, and MetfDeca decreased at similar concentrations to young adult control, while lipid peroxidation substantially ameliorated. Additionally, superoxide dismutase and catalase activity increased by 41 % and 42 % (DV), 39 % and 41 % (Metf), and 75 % and 73 % (MetfDeca). POV treatments reduced Nrf2 and GFAP immunoreactivity in CA1 (70-87.5 %), CA3 (60-80 %), and DG (57-89 %). Metformin treatment showed a minor effect, while MV treatment did not improve any parameters. Although DV, Metf, and MetfDeca treatments showed similar results, POVs doses were 16-fold fewer than Metformin. In conclusion, DV and MetfDeca could be pharmacological options to reduce age-related neuronal damage.

An in vitro redox adaptation model for metastatic prostate cancer: Establishing, characterizing, and Cabazitaxel response evaluating

Little is known about the redox-adapted cancer cells for understanding their pharmacologically targetable features and chemotherapeutic responses. Thus, we presented the first in vitro redox adaptation model for metastatic prostate cancer (mPC), LNCaP-HPR, with enhanced oxidative stress resistance accompanying poor Cabazitaxel response. After establishing, the cells were characterized by comparing the viability, death, oxidative stress, total GSH levels, and the mRNA and protein levels of the redox-sensitive transcription factors responsible for the adaptation, Nrf-2, NF-κB, and HIF-1α. Then, the apoptotic effect of Cabazitaxel was evaluated in LNCaP mPC, LNCaP-HPR, and C4-2 metastatic castration-resistant (mCRPC) cells. In response to H₂ O₂ , viability, oxidative stress, and the total GSH levels of LNCaP-HPR cells have confirmed the oxidative stress resistance. Nrf-2, NF-κB, and HIF-1α were upregulated in LNCaP-HPR cells, not in LNCaP, confirming that resistant cells were much less affected by exogenous oxidative stress. Unlike LNCaP, LNCaP-HPR cells were less sensitive to Cabazitaxel, as closer to the response of C4-2 mCRPC cells, indicating that redox adaptation decreased Cabazitaxel response. This is the first evaluated association between redox adaptation and poor Cabazitaxel response, suggesting that in vitro Cabazitaxel efficiency is affected by PC cells' endogenous oxidative stress tolerance. This article is protected by copyright. All rights reserved.

Comparative Studies of Orthovanadate Nanoparticles and Metformin on Life Quality and Survival of Senile Wistar Rats

Effect of prolong use of orthovanadate nanoparticles (GdVO₄/Eu³⁺ NPs (8 × 25 nm)) on life quality and survival of male Wistar rats on the late stage of ontogenesis (from 23 months to the end of life) has been investigated. Multi-parametric assessment of orthovanadate NPs influences against metformin (Met) which is a well-known calorie restriction mimetic (CR-mimetic) has been completed. The quality of life was assessed by taking into account age-related hallmarks-phenotype and some physiological parameters (condition of the coat, body weight, concentration of thyroxine, rectal temperature) as well as indicators of the pro-oxidant/antioxidant balance of blood and liver (the content of lipid hydroperoxides; aconitase, glutathione peroxidase, glutathione reductase, glutaredoxin activity, and activity of NADP⁺-dehydrogenases (DG) (glucose-6-phosphate DG, malate DG, and isocitrate DG)) in aging animals. Kaplan-Meier curve and Gehan tests with Yates' correction were performed for the survival analysis. It has been found that long-term use of GdVO₄/Eu³⁺ NPs (0.25-0.30 mg/kg/day), as well as Met (100-110 mg/kg/day) with drinking water led to reliable improvement of physiological parameters and normalization of the pro-oxidant/antioxidant balance in the liver and blood of experimental animals. A significant increase in the survival rate of aging rats was observed; the apparent median survival for control rats was 900 days, while for experimental rats, 1010 and 990 days for GdVO₄/Eu³⁺ NPs and Met, respectively. In general, the data obtained demonstrate the ability of GdVO₄/Eu³⁺ NPs and CR-mimetic-Met to improve the quality of life and increase the survival of an elderly organism.

Response of Cytoprotective and Detoxifying Proteins to Vanadate and/or Magnesium in the Rat Liver: The Nrf2-Keap1 System

Oxidative stress (OS) is a mechanism underlying metal-induced toxicity. As a redox-active element, vanadium (V) can act as a strong prooxidant and generate OS at certain levels. It can also attenuate the antioxidant barrier and intensify lipid peroxidation (LPO). The prooxidant potential of V reflected in enhanced LPO, demonstrated by us previously in the rat liver, prompted us to analyze the response of the nuclear factor erythroid-derived 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2-Keap1) system involved in cellular regulation of OS to administration of sodium metavanadate (SMV, 0.125 mg V/mL) and/or magnesium sulfate (MS, 0.06 mg Mg/mL). The levels of some Nrf2-dependent cytoprotective and detoxifying proteins, i.e., glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), glutamate cysteine ligase catalytic subunit (GCLC), glutathione synthetase (GSS), NAD(P) H dehydrogenase quinone 1 (NQO1), UDP-glucumno-syltransferase 1 (UGT1), and heme oxygenase 1 (HO-1); glutathione (GSH); metallothionein (MT1); and glutamate-cysteine ligase (GCL) mRNA were measured. We also focused on the V-Mg interactive effects and trends toward interactive action as well as relationships between the examined indices. The elevated levels of Nrf2, GCL mRNA, and GCL catalytic subunit (GCLC) confirm OS in response to SMV and point to the capacity to synthesize GSH. The results also suggest a limitation of the second step in GSH synthesis reflected by the unchanged glutathione synthetase (GSS) and GSH levels. The positive correlations between certain cytoprotective/detoxifying proteins (which showed increasing trends during the SMV and/or MS administration, compared to the control) and between them and malondialdehyde (MDA), the hepatic V concentration/total content, and/or V dose (discussed by us previously) point to cooperation between the components of antioxidant defense in the conditions of the hepatic V accumulation and SMV-induced LPO intensification. The V-Mg interactive effect and trend are involved in changes in Nrf2 and UGT1, respectively. The p62 protein has to be determined in the context of potential inhibition of degradation of Keap1, which showed a visible upward trend, in comparison with the control. The impact of Mg on MT1 deserves further exploration.

Anti-aging Effects of Antioxidant Rare-Earth Orthovanadate Nanoparticles in Wistar Rats

Biomedical application of rare-earth-based nanoparticles attracts much attention due to their unique optical and redox properties and quite low toxicity. Earlier, we found age-related beneficial effects of rare-earth-based orthovanadate nanoparticles (OV NPs) on the prooxidant/antioxidant balance in liver and blood of Wistar rats, as reported by Nikitchenko et al. (Biol Trace Elem Res (2020). https://doi.org/10.1007/s12011-020-02196-7 ). However, the question remained unclear whether OV NPs' redox activity directly defines the protection ability. In the present work, antiradical, antioxidant, and membrane-protective properties of GdYVO₄/Eu³⁺ NPs (1-2 nm), GdVO₄/Eu³⁺ NPs (8 × 25 nm), LaVO₄/Eu³⁺ (57 × 8 nm) were assayed in a comparative manner in various model systems. All OV NPs demonstrated the protective properties, but extra-small GdYVO₄/Eu³⁺ NPs revealed the weakest antioxidant efficacy. In isolated mitochondria, OV NPs lowered (most evidently-extra-small NPs) respiration and oxidative phosphorylation, as well as ATP concentration. We conclude that not only the direct antioxidant effect but also slight suppression of bioenergetic processes by the OV NPs as well as the triggering of GSH-dependent antioxidant system may represent the principal mechanisms of their beneficial influences in an aged organism. This statement is consistent with improvement of the oxidative balance of 33-month-old rats due to prolonged administration of GdVO₄ /Eu³⁺ NPs (for 11 months) accompanied by retention of the GSH signaling of the old rats at the level of 12 months mature animals. Consequently, an increase of antioxidant defense upon prolonged usage of OV NPs will lead to oxidative balance stabilization increasing the health span and survival of an organism.

Age-Related Effects of Orthovanadate Nanoparticles Involve Activation of GSH-Dependent Antioxidant System in Liver Mitochondria

Vanadium is an important ultra-trace element nowadays attracting attention with particular emphasis on medical application. But the therapeutic application of vanadium-based drugs is still questionable and restricted due to some toxic side effects. It was found that unique redox properties of vanadium in nanoform provided antioxidant activity and prevented oxidative disturbance in cells in vitro. Though, on the organism level, ambiguous effects of vanadium-based nanoparticles were observed. In this study, the age-related features of prooxidant/antioxidant balance in blood serum and liver mitochondrial and postmitochondrial fractions of 3 and 18-month-old Wistar male rats treated with orthovanadate nanoparticles (GdVO₄/Eu³⁺, 8 × 25 nm) within 2 months have been investigated. Prooxidant potential-related indexes were the content of lipid hydroperoxides as well as aconitase activity. Activity of glutathione peroxidase, glutathione-S-transferase, glutaredoxin, glutathione reductase, glucose-6-phosphate dehydrogenase, and NADPH-dependent isocitrate dehydrogenase designated the tissue antioxidant potential. Based on the obtained values, the integral index of the prooxidant/antioxidant balance-the reliability coefficient (Kr) has been calculated. The data show that due to activation some chain links of GSH-dependent antioxidant system, GdVO₄/Eu³⁺ nanoparticles increase the reliability of the prooxidant-antioxidant balance in tissues and especially in the liver mitochondria of old animals (Kr in mitochondria of young rats was 2.94, and in mitochondria of old ones-9.83 conventional units). Detected in vitro glutathione peroxidase-like activity of the GdVO₄/Eu³⁺ nanoparticles is supposed to be among factors increasing the reliability of the system. So, for the first time, the beneficial effect of the long-term orthovanadate nanoparticle consumption in old males has been discovered.

The Association of Cigarette Smoke Exposure with Lung Cellular Toxicity and Oxidative Stress: the Protective Role of Crocin

Cigarette smoke (CS) contains many free radicals and toxic chemicals. Nuclear erythroid-related factor-2 (Nrf2) is a transcriptional regulator of several phase II antioxidant genes, including glutamate-cysteine ligase (GCL). In this study, it was hypothesized that Crocin may mediate antioxidant signaling pathway to protect human lung epithelial cells against CS-mediated toxicity and oxidative stress via inducing glutathione (GSH) biosynthesis and activation of Nrf2 pathway. Alveolar epithelial cells (A549) were exposed to 1, 2.5 and 5% cigarette smoke extracts (CSE) with or without Crocin (500 μM). After 48 h exposure, the cytotoxicity, oxidant/antioxidant parameters and the Nrf2 pathway modification were assayed. Treatment of A549 cells with all concentrations of CSE dose dependently decreased cell viability, antioxidant levels, GCL and Nrf2 gene expression, which was associated with increased production of reactive oxygen species. Crocin not only restored CSE-depleted GSH levels by enhancing GCL expression via activation of Nrf2 but also quenched the CSE-generation and release of reactive oxygen species. Crocin attenuated CSE-mediated Nrf2 modifications, thereby inducing its nuclear accumulation associated with GCL gene transcription leading to enhanced GSH levels. By inducing GSH synthesis, Crocin attenuates CSE-mediated GSH depletion and protects cells against CSE-induced oxidative stress via Nrf2 pathway. These results may have implications in dietary modulation of natural antioxidants in treatment of pulmonary diseases.

Effect of dietary vanadium supplementation on growth performance, mineral balance and antioxidant activity in male Sahiwal calves

The study was aimed to examine the effect of supplementation of sodium metavandate (NaVO3) as source of vanadium on DMI intake, growth performance, antioxidant activity, level of mineral in plasma and their balance in male Sahiwal calves. The vanadium content in maize (Zea mays) and bajra (Pennisetum glaucum) grains was 58 ppb and 55 ppb while in berseem (Trifolium alexandrinum) and mustard (Brassica campestris) fodder it was 8.37 and 7.24 ppm, respectively. Male Sahiwal calves (20) of comparable age (6±0.82 months) and body weight (71±8.06 kg) were randomly allotted to 4 different treatments with replication of 5 animals in each. Supplementation was done with 0, 2, 4 and 8 ppm of vanadium in groups T1, T2, T3 and T4, respectively, for 120 days. Blood samples were collected at monthly intervals to examine antioxidant activity in blood, plasma and mineral levels. Feed consumption (DM intake, DM intake% BW) and growth rate did not show any significant effect of vanadium supplementation. Glutathione peroxidase activity was higher in groups T3 and T4 as compared to T1 and T2 whereas, SOD and catalase activity was similar in all the groups. Excretion and absorption patterns of Ca, P, Cu and Fe and their plasma levels were similar in different groups. However, vanadium and Zn balance and their plasma levels increased due to vanadium supplementation. The present study revealed that in growing calves, vanadium supplementation showed enhanced glutathione peroxidise activity, plasma Zn and vanadium levels.

Metformin-decavanadate treatment ameliorates hyperglycemia and redox balance of the liver and muscle in a rat model of alloxan-induced diabetes

MetfDeca treatment ameliorate glucose and insulin levels, and reduce the levels of oxidized glutathione, reactive oxygen species, malondialdehyde, and 4-hydroxyalkenal; the superoxide and catalase activities, and glutathione levels were regulated.

Vanadium in Biosphere and Its Role in Biological Processes

Ultra-trace elements or occasionally beneficial elements (OBE) are the new categories of minerals including vanadium (V). The importance of V is attributed due to its multifaceted biological roles, i.e., glucose and lipid metabolism as an insulin-mimetic, antilipemic and a potent stress alleviating agent in diabetes when vanadium is administered at lower doses. It competes with iron for transferrin (binding site for transportation) and with lactoferrin as it is secreted in milk also. The intracellular enzyme protein tyrosine phosphatase, causing the dephosphorylation at beta subunit of the insulin receptor, is inhibited by vanadium, thus facilitating the uptake of glucose inside the cell but only in the presence of insulin. Vanadium could be useful as a potential immune-stimulating agent and also as an antiinflammatory therapeutic metallodrug targeting various diseases. Physiological state and dose of vanadium compounds hold importance in causing toxicity also. Research has been carried out mostly on laboratory animals but evidence for vanadium importance as a therapeutic agent are available in humans and large animals also. This review examines the potential biochemical and molecular role, possible kinetics and distribution, essentiality, immunity, and toxicity-related study of vanadium in a biological system.

Inorganic Vanadium Supplementation in Crossbred Calves: Effects on Antioxidant Status, Immune Response and Haemato-Biochemical Attributes

The aim of the study was to assess the effect of inorganic vanadium (V) supplementation on antioxidant enzymes, immune status, and haemato-biochemical attributes of growing crossbred calves. Twenty-four male Karan Fries calves (Tharparkar × Holstein Friesian) (initial body mass 72.83 ± 2.5 kg; age 3-9 month) were randomly allocated to four groups: the control (received basal diet devoid of supplemental V), the 3 ppm (received basal diet with 3 mg/kg V), the 6 ppm (received basal diet with 6 mg/kg V) and the 9 ppm group (received basal diet with 9 mg/kg V). All the calves were fed for 150 days as per ICAR (2013) feeding standards to meet their nutrient requirements for 500 g growth rate/day. Peripheral blood samples were collected at the start of experiment and subsequently at 30, 60, 90, 120 and 150 days post-V supplementation for determination of antioxidant enzyme activity, immunological parameters and haemato-biochemical attributes. Results indicated that dietary supplementation of V did not affect daily gain, feed intake and haematological parameters. Crossbred calves fed with 9 mg V/kg diet showed reduced (P < 0.05) plasma total cholesterol concentration; however, plasma total protein and glucose concentration remained unaltered. Glutathione peroxidase (GPx) activity as well as immunoglobulin G (IgG) concentration was significantly (P < 0.05) higher in group supplemented with 9 mg V/kg DM; however, superoxide dismutase (SOD), catalase activity and total plasma immunoglobulin (Ig) concentration were similar in all experimental group. Dietary V supplementation showed a negative relation with plasma thiobarbituric acid reactive substances (TBARS) concentration, whereas non-esterified fatty acid (NEFA) concentration remained unaltered among all groups. Plasma V level increased (P < 0.05) with increasing dietary V levels without affecting levels of Ca, Mg, Fe, Cu and Zn. In conclusion, a dietary addition of 9 mg V/kg DM reduced cholesterol content and improved antioxidant and immune response in growing crossbred calves.

Hepatotoxicity of vanadyl sulfate in nondiabetic and streptozotocin-induced diabetic rats

This study examined the effects of vanadyl sulfate (VOSO₄) on the livers of nondiabetic and streptozotocin-induced diabetic rats. Rats were divided into 6 groups. Groups 1, 2, and 3 consisted of nondiabetic rats that were, respectively, control animals or those receiving an intraperitoneal (i.p.) injection of either 5 or 10 mg·kg^-1 (i.p.) VOSO₄ for 30 days. Groups 4, 5, and 6 consisted of diabetic animals that were, respectively, control animals or those treated with 5 or 10 mg·kg^-1 (i.p.) VOSO₄ for 30 days. Results showed that VOSO₄ reduced body mass in nondiabetic rats, whereas it increased body mass in diabetic groups. Plasma transaminases (aspartate aminotransferase, alanine aminotransferase), lactate dehydrogenase, and alkaline phosphatase activities and malondialdehyde levels were increased, while liver catalase and superoxide dismutase activities were profoundly decreased in diabetic animals in comparison with enzyme activities in the nondiabetic group. Rats in the diabetic group also showed notable oxidative damage to the liver. Treatment of diabetic rats with VOSO₄ decreased the hepatotoxic markers, significantly restored the activities of antioxidant enzymes, and attenuated histopathological changes in liver tissue. In nondiabetic rats, VOSO₄ treatment increased most of the hepatotoxic markers, reduced antioxidant enzyme activities, and induced pronounced oxidative damage in liver tissue. These data suggest that treatment with VOSO₄ exerts toxic effects in healthy animals and significantly prevents liver oxidative damage in streptozotocin-induced diabetic rats, but without total safety. Further studies are needed to clarify its mechanism of action.

Vanadate oxidative and apoptotic effects are mediated by the MAPK-Nrf2 pathway in layer oviduct magnum epithelial cells

Vanadium is a metal of high physiological, environmental and industrial importance. However, vanadium-induced oxidative stress can reduce the egg quality of poultry, and be potentially harmful to humans, and the underlying mechanism is not clear. In this study, we investigated the underlying relationship between the oxidant-sensitive mitogen-activated protein kinase (MAPK) signaling pathway and vanadium-induced oxidative stress in oviduct magnum epithelial (OME) cells. Cultured OME cells were treated with 100 μmol L^-1 vanadium and/or MAPK inhibitors [P38 MAPK inhibitor, SB203580; extracellular regulated protein kinase 1 and 2 (ERK1/2) inhibitor, U0126; c-JUN N-terminal kinases (JNK) inhibitor, SP600125]. Cell viability, apoptosis, and generation of reactive oxygen species (ROS) were assessed using flow cytometry. The expression of oxidative stress-related genes and their proteins was measured by reverse transcription-polymerase chain reaction and western blotting. Vanadium treatment reduced cell viability, whereas pretreated OME cells with SB203580 and U0126 prevented the reducing effect of vanadium on cell viability (P < 0.05). Likewise, MAPK inhibitors effectively suppressed vanadium-induced apoptosis and ROS generation (P < 0.05). In the OME cells treated with vanadium, SB203580 (P < 0.05) and SP600125 (P = 0.08) increased catalase activity by 89.3% and 55.3%; SB203580 and U0126 increased (P < 0.05) glutathione peroxidase activity by 44.9% and 51.1%, respectively. Incubation of OME cells with MAPK inhibitors also prevents malondialdehyde concentration increase and lactic dehydrogenase activity decrease in response to vanadium (P < 0.05). Vanadium downregulated P38, ERK1/2, JNK, Nrf2, sMaf, GCLC, NQO1 and HO-1 mRNA expression (P < 0.05). In contrast, inhibition of JNK with SP600125 upregulated P38, ERK1/2, JNK, Nrf2, GCLC and HO-1 mRNA expression (P < 0.05); inhibition of P38 with SB203580 upregulated JNK, NQO1 and HO-1 mRNA expression (P < 0.05); and inhibition of ERK1/2 with U0126 upregulated ERK1/2, GCLC and HO-1 mRNA expression (P < 0.05). Moreover, phosphorylation of P38, ERK1/2, JNK, and Nrf2 proteins was enhanced by V incubation; however, SP600125 blocked the phosphorylation of these proteins, whereas SB203580 blocked the phosphorylation of P38 and Nrf2. These results indicate that vanadium inducing oxidative stress in OME cells might be, at least, associated with the phosphorylation of the P38MAPK/JNK-Nrf2 pathway, which reduces the expression of phase II detoxifying enzymes.

Glutathione and Glutathione Transferase Omega 1 as Key Posttranslational Regulators in Macrophages

Macrophage activation during phagocytosis or by pattern recognition receptors, such as Toll-like receptor 4, leads to the accumulation of reactive oxygen species (ROS). ROS act as a microbicidal defense mechanism, promoting clearance of infection, allowing for resolution of inflammation. Overproduction of ROS, however, overwhelms our cellular antioxidant defense system, promoting oxidation of protein machinery, leading to macrophage dysregulation and pathophysiology of chronic inflammatory conditions, such as atherosclerosis. Here we will describe the role of the antioxidant tripeptide glutathione (GSH). Until recently, the binding of GSH, termed glutathionylation, was only considered to maintain the integrity of cellular components, limiting the damaging effects of an aberrant oxidative environment. GSH can, however, have positive and negative regulatory effects on protein function in macrophages. GSH regulates protein secretion, driving tumor necrosis factor α release, hypoxia-inducible factor-1α stability, STAT3 phosphorylation, and caspase-1 activation in macrophages. GSH also plays a role in host defense against Listeria monocytogenes, modifying the key virulence protein PrfA in infected macrophages. We will also discuss glutathione transferase omega 1, a deglutathionylating enzyme recently shown to play a role in many aspects of macrophage activity, including metabolism, NF-κB activation, and cell survival pathways. Glutathionylation is emerging as a key regulatory event in macrophage biology that might be susceptible to therapeutic targeting.

Ameliorative effect of an oxovanadium (IV) complex against oxidative stress and nephrotoxicity induced by cisplatin

OBJECTIVE

The present study was designed to investigate the chemoprotective efficacy of an L-cysteine-based oxovanadium (IV) complex, namely, oxovanadium (IV)-L-cysteine methyl ester complex (VC-IV) against cisplatin (CDDP)-induced renal injury in Swiss albino mice.

METHODS

CDDP was administered intraperitoneally (5 mg/kg body weight) and VC-IV was administered orally (1 mg/kg body weight) in concomitant and 7 days pre-treatment schedule.

RESULTS

CDDP-treated mice showed marked kidney damage and renal failure. Administration of VC-IV caused significant attenuation of renal oxidative stress and elevation of antioxidant status. VC-IV also significantly decreased serum levels of creatinine and blood urea nitrogen, and improved histopathological lesions. Western blot analysis of the kidneys showed that VC-IV treatment resulted in nuclear translocation of nuclear factor E2-related factor 2 (Nrf2) through modulation of cytosolic Kelch-like ECH-associated protein 1. Thus, VC-IV stimulated Nrf2-mediated activation of antioxidant response element (ARE) pathway and promoted expression of ARE-driven cytoprotective proteins, heme oxygenase 1 and NAD(P)H:quinone oxidoreductase 1, and enhanced activity of antioxidant enzymes. Interestingly, VC-IV did not alter the bioavailability and renal accumulation of CDDP in mice.

DISCUSSION

In this study, VC-IV exhibited strong nephroprotective efficacy by restoring antioxidant defense mechanisms and hence may serve as a promising chemoprotectant in cancer chemotherapy.

High-Fat Diet Increased Renal and Hepatic Oxidative Stress Induced by Vanadium of Wistar Rat

The study was conducted to assess the effect of vanadium (V) in high-fat diet on the liver and kidney of rats in a 5-week trial. Seventy-two female Wistar rats (BW = 95 ± 5 g) were randomly allotted into eight groups. Groups I, II, III, and IV obtained low-fat diet containing 0, 3, 15, and 30 mg/kg V, and V, VI, VII, and VIII groups received the respective vanadium doses with high-fat diet, respectively. There were lesions in the liver and kidney of V, VI, VII, and VIII groups, granular degeneration and vacuolar degeneration were observed in the renal tubular and glomerulus epithelial cells, and hepatocytes showed granular degeneration and vacuolar degeneration. Supplemented high-fat diet with vanadium was shown to decrease (P < 0.05) activities of superoxide dismutase, total antioxidant capacity, glutathione-S transferase, and NAD(P)H/quinone oxidoreductase 1 (NQO1) and increase malondialdehyde content in the liver and kidney. The relative expression of hepatic nuclear factor erythroid 2-related factor 2 (Nrf-2) and NQO1 mRNA was downregulated by V addition and high-fat diet, and the effect of V was more pronounced in high-fat diet (interaction, P < 0.05), with VIII group having the lowest mRNA expression of Nrf-2 and NQO1 in the liver and kidney. In conclusion, it suggested that dietary vanadium ranging from 15 to 30 mg/kg could lead to oxidative damage and vanadium accumulation in the liver and kidney, which caused renal and hepatic toxicity. The high-fat diet enhanced vanadium-induced hepatic and renal damage, and the mechanism was related to the modulation of the hepatic and renal mRNA expression of Nrf-2 and NQO1.

Vanadium(III)-L-cysteine protects cisplatin-induced nephropathy through activation of Nrf2/HO-1 pathway

Cisplatin (CDDP) is one of the first-line anticancer drugs; however, the major limitation of CDDP therapy is development of nephrotoxicity (25-35% cases), whose precise mechanism mainly involves oxidative stress, inflammation and cell death. Therefore, in search of a potential chemoprotectant, an organovanadium complex, viz., vanadium(III)-L-cysteine (VC-III) was evaluated against CDDP-induced nephropathy in mice. CDDP was administered intraperitoneally (5 mg/kg b.w.) and VC-III was given by oral gavage (1 mg/kg b.w.) in concomitant and pre-treatment schedule. The results showed that VC-III administration reduced (p < 0.001) serum creatinine and blood urea nitrogen levels, suggesting amelioration of renal dysfunction. VC-III treatment also significantly (p < 0.001) prevented CDDP-induced generation of reactive oxygen species, reactive nitrogen species, and onset of lipid peroxidation in kidney tissues of the experimental mice. In addition, VC-III also substantially (p < 0.001) restored CDDP-induced depleted activities of the renal antioxidant enzymes such as, superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, and glutathione (reduced) level. Furthermore, histopathological study also confirmed the renoprotective efficacy of VC-III. Western blotting analysis appended by immunohistochemical data showed that VC-III treatment quite effectively reduced the expression of proinflammatory mediators such as, NFκβ, COX-2 and IL-6. VC-III administration also stimulated Nrf2-mediated antioxidant defense system by promotion of downstream antioxidant enzymes, such as HO-1. Moreover, treatment with VC-III significantly (p < 0.001) enhanced CDDP-mediated cytotoxicity in MCF-7 and NCI-H520 human cancer cell lines. Thus, VC-III can serve as a suitable chemoprotectant and increase the therapeutic window of CDDP in cancer patients.

Cyclooxygenase-1 as the main source of proinflammatory factors after sodium orthovanadate treatment

Vanadium is a metal present in air pollution. Its compounds may have both anticancer and carcinogenic properties. Vanadium compounds are tested in treatment of diabetes and cancer. An important research direction aimed at better understanding of the mechanisms of action of the vanadium compounds is a more detailed insight into their impact on inflammatory reactions. The aim of this study was to examine the effect of micromolar concentrations of sodium orthovanadate, Na3VO4, on the activity and expression of cyclooxygenases: COX-1 and COX-2. PMA-activated THP-1 macrophages were incubated in vitro for 48 h with micromolar concentrations of sodium orthovanadate. As shown by an ELISA assay, sodium orthovanadate increases the quantity of prostaglandin E2 being released into the medium in a dose-dependent manner as well as impacts the quantity of the stable metabolite of thromboxane A2: thromboxane B2. The use of a COX-2 inhibitor, NS-398, revealed that this effect was independent of changes in the activity of COX-2. Western blotting analysis showed that sodium orthovanadate increased the expression of COX-2 when used with NS-398. Quantitative real-time PCR measurements of mRNA levels of genes PTGS1 and PTGS2 revealed no effect of the tested vanadium compound on the levels of analyzed transcripts.