Evaluation of epirubicin-induced acute oxidative stress toxicity in rat liver cells and mitochondria, and the prevention of toxicity through quercetin administration

Determination of In Vitro and In Vivo Effects of Taxifolin and Epirubicin on Epithelial-Mesenchymal Transition in Mouse Breast Cancer Cells

Background: One of the most significant characteristics of cancer is epithelial-mesenchymal transition and research on the relationship between phenolic compounds and anticancer medications and epithelial-mesenchymal transition is widespread. Methods: In order to investigate the potential effects of Taxifolin on enhancing the effectiveness of Epirubicin in treating breast cancer, specifically in 4T1 cells and an allograft BALB/c model, the effects of Taxifolin and Epirubicin, both individually and in combination, were examined. Cell viability assays and cytotoxicity assays in 4T1 cells were performed. In addition, 4T1 cells were implanted into female BALB/c mice to conduct in vivo studies and evaluate the therapeutic efficacy of Taxifolin and Epirubicin alone or in combination. Tumor volumes and histological analysis were also assessed in mice. To further understand the mechanisms involved, we examined the messenger RNA and protein levels of epithelial-mesenchymal transition-related genes, as well as active Caspase-3/7 levels, using quantitative real-time polymerase chain reaction, western blot, and enzyme-linked immunosorbent assays, respectively. Results: In vitro results demonstrated that the coadministration of Taxifolin and Epirubicin reduced cell viability and cytotoxicity in 4T1 cell lines. In vivo, coadministration of Taxifolin and Epirubicin suppressed tumor growth in BALB/c mice with 4T1 breast cancer cells. Additionally, this combination treatment significantly increased the levels of active caspase-3/7 and downregulated the messenger RNA and protein levels of N-cadherin, β-catenin, vimentin, snail, and slug, but upregulated the E-cadherin gene. It significantly decreased the messenger RNA levels of the Zeb1 and Zeb2 genes. Conclusion: The in vitro and in vivo results of our study indicate that the concurrent use of Epirubicin with Taxifolin has supportive effects on breast cancer treatment.

Artemisia annua Extract Attenuate Doxorubicin-Induced Hepatic Injury via PI-3K/Akt/Nrf-2-Mediated Signaling Pathway in Rats

Doxorubicin (DOX), which is used to treat cancer, has harmful effects that limit its therapeutic application. Finding preventative agents to thwart DOX-caused injuries is thus imperative. Artemisia annua has numerous biomedical uses. This study aims to investigate the attenuative effect of Artemisia annua leaf extract (AALE) treatment on DOX-induced hepatic toxicity in male rats. A phytochemical screening of AALE was evaluated. Forty male rats were used; G1 was a negative control group, G2 was injected with AALE (150 mg/kg) intraperitoneally (i.p) daily for a month, 4 mg/kg of DOX was given i.p to G3 once a week for a month, and G4 was injected with DOX as G3 and with AALE as G2. Body weight changes and biochemical, molecular, and histopathological investigations were assessed. The results showed that AALE contains promising phytochemical constituents that contribute to several potential biomedical applications. AALE mitigated the hepatotoxicity induced by DOX in rats as evidenced by restoring the alterations in the biochemical parameters, antioxidant gene expression, and hepatic histopathological alterations in rats. Importantly, the impact of AALE against the hepatic deterioration resulting from DOX treatment is through activation of the PI-3K/Akt/Nrf-2 signaling, which in turn induces the antioxidant agents.

Epirubicin toxicity in rat's ovary and uterus: A protective role of 3-Indolepropionic acid supplementation

The "anthracycline, Epirubicin (EPI)," in managing breast cancer, is highly cytotoxic. Tryptophan-derived 3-indolepropionic acid (3-IPA) decreases oxidative damage, and its prospect of alleviating EPI-induced cytotoxicity was examined in rats' hypothalamus-ovary-uterus axis. Female rats: Control, EPI (2.5 mg/kg), 3-IPA alone (40 mg/kg), EPI+3-IPA (2.5 mg/kg + 20 mg/kg), EPI + 3-IPA2 (2.5 mg/kg + 40 mg/kg) were treated for 28 days. Subsequently, reproductive hormones, oxidative and inflammatory stress biomarkers, and tissue histology were examined. 3-IPA prevented EPI-induced decreases in the follicle-stimulating hormone, estradiol, progesterone and prolactin levels. EPI-mediated reduction in antioxidant enzymes, reduced glutathione and total sulfhydryl groups were partially counteracted by 3-IPA co-treatment. Increased oxidative and inflammatory stress biomarkers caused by treatment with EPI alone were lessened by 3-IPA co-treatment. Also, 3-IPA reduced histological damage in the examined tissues. Conclusively, 3-IPA ameliorated biochemical markers and tissue injury caused by EPI treatment alone via an antioxidative and anti-inflammatory mechanism while stabilising serum hormone dynamics.

Protective effects of sinomenine hydrochloride on lead-induced oxidative stress, inflammation, and apoptosis in mouse liver

Lead, one of the most common heavy metal toxins, seriously affects the health of humans and animals. Sinomenine hydrochloride (SH) shows antioxidative, anti-inflammatory, antiviral, and anticancer properties. Hence, this study investigated the protective effects of SH against Pb-induced liver injury and explored the underlying mechanisms. First, a mouse model of lead acetate (0.5 g/L lead acetate in water, 8 weeks) was established, and SH (100 mg/kg bw in water, 8 weeks) intervention was administered by gavage. Then, the protective effect of SH against lead-induced liver injury was evaluated through serum biochemical analysis, histopathological analysis, and determination of malondialdehyde (MDA) and total antioxidant capacity (T-AOC) levels. The messenger RNA (mRNA) expression levels of the cytokines IL-1β and TNF-α and the apoptosis factors Bax, Bcl-2, and Caspase3 in the liver were detected by quantitative real-time PCR. Then, the expression levels of IL-1β and TNF-α in the liver were detected by ELISA. Immunohistochemical determination of the expression of the apoptosis factors Bax, Bcl-2, and Caspase3 was performed. SH treatment reduced the levels of liver alanine aminotransferase, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and MDA in Pb-treated mice, indicating that SH protected the liver from injury and oxidative stress in Pb-treated mice. SH also increased the liver T-AOC of Pb-treated mice. Quantitative real-time PCR, ELISA, and immunohistochemical analysis showed that SH inhibited apoptosis, as indicated by the regulation of the mRNA expression of Bax and Bcl-2 and the reduced expression of Caspase3 and pro-inflammatory factors (IL-1β and TNF-α) in the livers of Pb-treated mice. These results suggest that SH protects the mouse liver from Pb-induced injury. The underlying mechanism involves antioxidative, anti-inflammatory, and anti-apoptotic processes.

Rutin and Quercetin Counter Doxorubicin-Induced Liver Toxicity in Wistar Rats via Their Modulatory Effects on Inflammation, Oxidative Stress, Apoptosis, and Nrf2

The presented study was performed to verify whether rutin and/or quercetin can inhibit liver injury induced by doxorubicin (DXR) in male Wistar rats. In this study, male Wistar rats were treated via the oral route with rutin and quercetin (50 mg/kg) either alone or in combination every other day for five weeks concomitant with receiving intraperitoneal DXR (2 mg/kg) two times a week for five successive weeks. Quercetin, rutin, and their combination significantly improved the deteriorated serum AST, ALT, and ALP activities and total bilirubin level, as well as albumin, AFP, and CA 19.9 levels in DXR-injected rats. Treatments of the DXR-injected group with quercetin and rutin prevented the elevation in liver lipid peroxidation and the reduction in superoxide dismutase, glutathione-S-transferase and glutathione peroxidase activities, and glutathione content. Treatments with quercetin and rutin significantly repressed the elevated expression of liver p53 and TNF-α and enhanced Nrf2 expression. Furthermore, the treatments significantly reduced DXR-induced liver histological changes. In conclusion, rutin and quercetin either alone or in combination may have potential preventive effects against DXR-induced hepatotoxicity through inhibiting oxidative stress, inflammation, and apoptosis as well as modulating the Nrf2 expression.

The Effect of Flammulina velutipes Polysaccharide on Immunization Analyzed by Intestinal Flora and Proteomics

Proteomics and intestinal flora were used to determine the mechanism of immune modulatory effects of Flammulina velutipes polysaccharide on immunosuppressed mice. The results showed that compared with the model group, F. velutipes polysaccharide could increase thymus and spleen indices and improve thymus tissue structure in mice; IL-2 and IL-4 contents were significantly increased and IL-6 and TNF-α contents were significantly decreased; serum acid phosphatase (ACP), lactate dehydrogenase (LDH) and total antioxidant capacity (T-AOC) activities were increased (P < 0.05); in the liver, superoxide dismutase (SOD) and catalase (CAT) activities were increased (P < 0.001), while malondialdehyde (MDA) content was decreased (P < 0.001). Proteomics discovered that F. velutipes polysaccharides may exert immune modulatory effects by participating in signaling pathways such as immune diseases, transport and catabolism, phagosomes and influenza A, regulating the immune-related proteins Transferrin receptor protein 1 (TFRC) and Radical S-adenosyl methionine domain-containing protein 2 (RSAD2), etc. Gut microbial studies showed that F. velutipes polysaccharides could increase the abundance of intestinal flora and improve the flora structure. Compared to the model group, the content of short-chain fatty acids (SCFAs) and the relative abundance of SCFA-producers Bacteroides and Alloprevotella were increased in the F. velutipes polysaccharide administration group, while Lachnospiraceae_NK4A136_group and f_Lachnospiraceae_Unclassified decreased in relative abundance. Thus, F. velutipes polysaccharide may play an immunomodulatory role by regulating the intestinal environment and improving the balance of flora.

Gp130 degradation induced by epirubicin contributes to chemotherapy efficacy

Two anthracyclines, doxorubicin and epirubicin have been widely used alone or in combination with other antitumor reagents in the chemotherapeutic treatment of various malignancies. Although therapeutic efficacy of anthracyclines has been studied extensively, precise cytotoxic mechanism of these drugs is not been completely elucidated. Here we show that epirubicin-induced degradation of transmembrane protein gp130 contributes to antitumor effect of epirubicin. gp130 is degraded by epirubicin in a proteasome- and autophagy-dependent manner. Epirubicin induces activation of p38-MK2 signaling pathway to phosphorylate gp130 at Ser 782, which results in gp130 internalization and degradation by lysosome. Although mutation of Ser 782 to Ala or Cys in gp130 upregulates global epirubicin-induced autophagy, reduced degradation of gp130 accompanied with enhanced Stat3 phosphorylation at tyrosine 705 is observed. We also show that epirubicin-resistant tumor cells express higher level of gp130. Altogether, our results indicate that degradation of gp130 and subsequent reduction of gp130-Stat3 signaling contributes to epirubicin-induced tumor cell death.

A systematic review on hepatoprotective activity of quercetin against various drugs and toxic agents: Evidence from preclinical studies

Quercetin is one of the most abundant flavonoids in human diet that has been reported to exhibit a wide range of pharmacological properties. The biochemical and molecular mechanisms involved in the hepatoprotective activity of quercetin were discussed in this review. Quercetin exhibited hepatoprotective activity against 2-butoxyethanol, acrylamide, acrylonitrile, aflatoxin B1, aroclor-1254, arsenic, sodium arsenite, azathioprine, cadmium chloride, carbon tetrachloride, chlorpyrifos, cyclosporine A, diazinon, dimethylnitrosamine, doxorubicin, epirubicin, ethanol, fenvalerate, isoniazide, rifampicin, lead acetate, lindane, D-galactosamine, methotrexate, methylmercury, nickel sulfate, paracetamol, perfluorooctanoic acid, polychlorinated biphenyls, pyrrolizidine alkaloid clivorine, rotenone, sodium fluoride, streptazotocin, tert-butyl hydroperoxide, thioacetamide, titanium dioxide, tumor necrosis factor-α, tripterygium glycoside, triptolide, ultraviolet A light, concavalin A, bisphenol, and ischemia-induced hepatotoxicity in various animal models due to its antioxidant, free radical-scavenging,anti-inflammatory, antiapoptotic, and cytochrome P450 2E1 (CYP2E1) inhibitory activities. In this review, we provide an overview of the possible mechanisms by which quercetin reduced the hepatotoxicity of different hepatotoxicants. This will help the toxicologists, pharmacologists, and chemists to develop new safer pharmaceutical products with quercetin and other hepatotoxicants.

Ameliorative effect of Magnesium Isoglycyrrhizinate on hepatic encephalopathy by Epirubicin

BACKGROUND

The purpose of the present study was to evaluate the protective effect of Magnesium Isoglycyrrhizinate (MI) on Epirubicin (EPI)-induced hepatic encephalopathy (HE) and explore its underlying mechanism.

METHODS

Mice were divided randomly into groups for treatments as follows: control group, EPI group (Model group), EPI + MI (25, 50 mg/kg) group. Morris water maze test were conducted to evaluate the spatial learning and memory ability. The serum and hippocampus levels of oxidative stress or inflammation were uncovered with the detection of superoxide dismutase (SOD), malondialdehyde (MDA), and pro-inflammatory cytokines (IL-1β, IL-6, TNF-α).

RESULTS

As a result, treatment with MI effectively ameliorated the EPI-induced decline in the ability of spatial learning and memory. MI also significantly relieved the severity of oxidative stress or inflammation in serum and hippocampus, which was accompanied with regulating liver functional parameters. Western blot data demonstrated that administration of MI could regulate the redox-related expressions of Txnip, Trx, Nrf2, HO-1, p-IκB-α, p-NF-κB, Caspase-3, Caspase-9, Bax and Bcl-2 in EPI-stimulated hepatic encephalopathy (HE). And the potency of MI treatments on Nrf2, NF-κB expression was also confirmed with immunohistochemical analysis.

CONCLUSIONS

Taken together, the protective effect of Magnesium Isoglycyrrhizinate on EPI-induced hepatic encephalopathy might be mediated via the Txnip/Nrf2/NF-κB signaling pathway.

Resveratrol and Quercetin Administration Improves Antioxidant DEFENSES and reduces Fatty Liver in Metabolic Syndrome Rats

Mixtures of resveratrol (RSV) + quercetin (QRC) have antioxidant properties that probably impact on fatty liver in metabolic syndrome (MS) individuals. Here, we study the effects of a mixture of RSV + QRC on oxidative stress (OS) and fatty liver in a rat model of MS. Weanling male Wistar rats were separated into four groups (n = 8): MS rats with 30% sucrose in drinking water plus RSV + QRC (50 and 0.95 mg/kg/day, respectively), MS rats without treatment, control rats (C), and C rats plus RSV + QRC. MS rats had increased systolic blood pressure, triglycerides, insulin levels, insulin resistance index homeostasis model (HOMA), adiponectin, and leptin. The RSV + QRC mixture compensated these variables to C values (p < 0.01) in MS rats. Lipid peroxidation and carbonylation were increased in MS. Total antioxidant capacity and glutathione (GSH) were decreased in MS and compensated in MS plus RVS + QRC rats. Catalase, superoxide dismutase isoforms, peroxidases, glutathione-S-transferase, glutathione reductase, and the expression of Nrf2 were decreased in MS and reversed in MS plus RVS + QRC rats (p < 0.01). In conclusion, the mixture of RSV + QRC has benefic effects on OS in fatty liver in the MS rats through the improvement of the antioxidant capacity and by the over-expression of the master factor Nrf2, which increases the antioxidant enzymes and GSH recycling.

Multi-Component Herbal Products in the Prevention and Treatment of Chemotherapy-Associated Toxicity and Side Effects: A Review on Experimental and Clinical Evidences

Chemotherapy is nowadays the main treatment of human cancers. Chemotherapeutic agents target rapidly dividing cancer cells to suppress tumor progression, however, their non-specific cytotoxicity often leads to significant side effects that might be intolerable to cancer patients. Multi-component herbal products have been used for thousands of years for the treatment of multiple human diseases. This study aims to systematically summarize and evaluate the experimental and clinical evidences of the efficacy of multi-component herbal products in improving chemotherapy-induced side effect. Literature was retrieved from PubMed database and evaluated based on the side effects described. Multi-component herbal products were found to be effective in ameliorating the neurotoxicity, gastrointestinal toxicity, hematological toxicity, cardiotoxicity, hepatotoxicity and nephrotoxicity. Both experimental and clinical evidences were found, indicating the potential of applying multicomponent herbal products in the clinical treatment of chemotherapy-induced side effects. However, the lack of mechanistic and pharmacokinetic studies, inconsistency in product quality, as well as insufficient clinical evidence suggested that more investigations are urgently necessary. In all, our review shed light on the potential of using multi-component herbal products in the clinical management of chemotherapy-induced toxicity and side effects. We also discussed the potential threats of natural products for cancer treatment and compared the advantages of using herbs to conventional chemical drugs.

Alteration of membrane integrity and respiratory function of brain mitochondria in the rats chronically exposed to a low dose of acetamiprid

The pesticides are used in several fields of agriculture and farms to protect crops against harmful insects and herbs. The increased and uncontrolled use of these pollutants is very hazardous for the population health. Consumption of contaminated food matrices with these pesticides could impair the cell integrity and its molecular function. The main aim of this present study was to evaluate the alteration of the integrity of mitochondrial membranes and respiratory chain potential in the brain of rats exposed during 90 days to acetamiprid (AC), organochlorine of the new generation. After oral administration of AC in rats with 3.14 mg/kg of body weight, the results of this current study showed enhance in mitochondrial oxidative stress status by significant decrease of glutathione (GSH) level, glutathione pyroxidase (GPx), and catalase (CAT) activities. On the other hand, there is an increase in the enzymatic activity of the glutathione s-transferase (GST) and superoxide dismutase (SOD); at the same time, the MDA level was also highly increased. Furthermore, evaluation results of brain mitochondrial integrity revealed a significant increase in membrane permeability and mitochondrial swelling in rats exposed chronically to AC. Instead, other results of this present work showed a significant decrease in mitochondrial respiration potent (O₂ consumption) in acetamiprid-treated rats. In conclusion, the long duration exposition of the animals to AC has led to respiratory chain dysfunction, disturbance of matrix oxidative status, and a loss of mitochondrial membranes integrity.

Impairment of mitochondrial integrity and redox status in brain regions during a low-dose long-term exposition of rats to pyrethrinoïds: the preventive effect of quercetin

Pyrethrinoïds are synthetic pesticides widely used in agriculture and farms to protect crops from weeds, insects, fungi, and molds. Increased and uncontrolled use of these pollutants can have harmful effects on human health via consumption of contaminated food products. In the present study, deltamethrin (DLT = 3.72 mg/kg) and Bifenthrin (BF = 2.6 mg/kg) were used during a long-term exposition in the rats to assess their effect on mitochondrial integrity and function in different brain areas (hippocampus, striatum, cortex, and cerebellum). The results of this study have shown that chronic treatment of rats by both DLT and BF, on their own or in a mixture, has induced a significant increase in mitochondrial MDA, but when quercetin (Que) was co-administered with pesticides, this enhancement has been prevented in the almost of treated rats compared to solvent and control groups. In hippocampus area, GSH has significantly increased in all treated rats, except for BF and DLT-Que.-treated groups. In striatum, GSH has been depleted in the BF and DLT-treated groups compared to control and solvent groups; in contrast, when Que. was associated with pesticides, the rate of this tripeptide has been maintained at normal levels. In the cortex and cerebellum, GSH has been depleted significantly in all treated animals but has increased in DLT-Que. and mixture-Que.-treated groups in the cerebral cortex, at the same time; it has been maintained at normal levels in BF-Que.-treated groups in the cerebellum compared to control and solvent rats. On the other side, the results of this study have shown a loss of catalase (CAT) and glutathione S-transferase (GST) activities in all brain regions of pesticide-treated rats, but such a fall in enzymatic activities has been prevented by Que. when it was co-administered to rats with pesticides at the dose of 5 mg/kg, except in the cerebellum. In addition, this study has shown mitochondria's swelling in almost all the brain areas with exception of the cerebellum, providing information about a loss of mitochondrial membrane integrity in brain neurons of rats exposed to pyrethrinoïds. Furthermore, preventive administration of Que., in association with pesticides (5 mg/kg) or their mixture (10 mg/kg), has prevented mitochondria swelling in almost all of the analyzed brain tissues.

Exogenous antioxidants--Double-edged swords in cellular redox state: Health beneficial effects at physiologic doses versus deleterious effects at high doses

The balance between oxidation and antioxidation is believed to be critical in maintaining healthy biological systems. Under physiological conditions, the human antioxidative defense system including e.g., superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH) and others, allows the elimination of excess reactive oxygen species (ROS) including, among others superoxide anions (O₂^.-), hydroxyl radicals (OH.), alkoxyl radicals (RO.) and peroxyradicals (ROO.). However, our endogenous antioxidant defense systems are incomplete without exogenous originating reducing compounds such as vitamin C, vitamin E, carotenoids and polyphenols, playing an essential role in many antioxidant mechanisms in living organisms. Therefore, there is continuous demand for exogenous antioxidants in order to prevent oxidative stress, representing a disequilibrium redox state in favor of oxidation. However, high doses of isolated compounds may be toxic, owing to prooxidative effects at high concentrations or their potential to react with beneficial concentrations of ROS normally present at physiological conditions that are required for optimal cellular functioning. This review aims to examine the double-edged effects of dietary originating antioxidants with a focus on the most abundant compounds, especially polyphenols, vitamin C, vitamin E and carotenoids. Different approaches to enrich our body with exogenous antioxidants such as via synthetic antioxidants, diets rich in fruits and vegetables and taking supplements will be reviewed and experimental and epidemiological evidences discussed, highlighting that antioxidants at physiological doses are generally safe, exhibiting interesting health beneficial effects.

Pharmacological safety evaluation of a traditional herbal medicine "Zereshk-e-Saghir" and assessment of its hepatoprotective effects on carbon tetrachloride induced hepatic damage in rats

ETHNOPHARMACOLOGICAL RELEVANCE

"Zereshk-e-Saghir" (ZES), one of the traditional herbal medicines in old manuscripts of Persian hakims, has been used for the treatment of liver disorders. This current study is aimed to evaluate ZES effects on animal model to investigate its safety and hepatoprotective activity.

MATERIALS AND METHODS

ZES was prepared according to a traditional method by blending aqueous extracts of Berberis vulgaris L., with fine particles of other plants including Rosa damascene Mill, Cichorium intybus L., Cucumis sativus L., Portulaca oleracea L., Rheum palmatum L., and Nardostachys jatamansi DC.. The lethality of ZES was determined in male NMRI mice. Acute organ toxicity of ZES (750 and 1500mg/kg for 15 days, orally) was evaluated by measuring the cell blood count, liver marker enzymes, creatinine, antioxidant status and histopathological examinations in rats. CCl4-induced liver toxicity was used to examine the hepatoprotective effects of the preparation. The rats were pretreated with 250, 500, 750 and 1500mg/kg ZES by gavage for 15 days. At day 16, the rats were intraperitoneally injected 1ml/kg CCl4 in olive oil. Forty-eight hours after CCl4 injection, the animals were sacrificed and their liver samples and blood were collected for determination of alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase (ALT, AST, and ALP), histopathological examinations and antioxidant status.

RESULTS

Treatment of the mice with a single dose of ZES up to 2g/kg did not cause mortality. Treatment of the rats with doses of 750 and 1500mg/kg for 15 days showed no significant hematotoxicity and hepatotoxicity. Treatment of the rats with ZES reduced the increased serum levels of ALT, AST, and ALP induced by CCl4 at the doses of 250, 500, and 750mg/kg. This was almost confirmed by histopathological examinations. Pretreatment with ZES also decreased lipid peroxidation and maintained the levels of glutathione and total antioxidant capacity.

CONCLUSIONS

The present in vivo study revealed that the long term usage of ZES was safe for organs in laboratory animals. Meanwhile, prescribing the traditionally-recommended dose of ZES can be probably used against the liver injuries induced by xenobiotics. Further studies in other models of liver injuries are recommended for finding the exact hepatoprotective mechanism of ZES.

Protective effect of astragalus polysaccharides on liver injury induced by several different chemotherapeutics in mice

Side effects are an unavoidable consequence of chemotherapy drugs, during which liver injury often takes place. The current study was designed to investigate the protective effect of Astragalus polysaccharides (APS) against the hepatotoxicity induced by frequently-used chemical therapy agents, cyclophosphamide (CTX), docetaxel (DTX) and epirubicin (EPI)) in mice. Mice were divided into five groups, controls, low or high dose groups (DTXL, CTXL, EPIL or DTXH, CTXH, EPIH), and low or high dose chemotherapeutics+APS groups (DTXL+APS, CTXL+APS, EPIL+APS or DTXH+APS, CTXH+APS, EPIH+APS). Controls were treated with equivalent normal saline for 28 days every other day; low or high dose group were intraperitoneal (i.p) injected with low or high doses of CTX, DTX and EPI for 28 days every other day; low or high dose chemotherapeutics+APS group were separately intraperitoneal (i.p) injected with chemotherapeutics for 28 days every other day and i.p with APS (100 mg/kg) for 7 days continually from the 22th to the 28th days. The body weight, serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), histopathological features, and ultrastructure morphological change of liver tissues, protein expression level of caspase-3 were estimated at different time points. With high dose treatment of DTX, CTX and EPI, weight gain was inhibited and serum levels of ALT and AST were significantly increased. Sections of liver tissue showed massive hepatotoxicity in CTXH group compared to the control group, including hepatic lobule disorder, granular and vacuolar degeneration and necrosis in hepatic cells. These changes were confirmed at ultrastructural level, including obvious pyknosis, heterochromatin aggregation, nuclear membrane resolution, and chondrosome crystal decrease. Western blotting revealed that the protein levels of caspase-3 increased in CTXH group. The low dose groups exhibited trivial hepatotoxicity. More interestingly, after 100 mg/kg APS, liver injury was redecued not only regarding serum transaminase activities (low or high dose chemotherapeutics+APS group), but also from pathological and ultrastructural changes and the protein levels of caspase-3 (CTXH+APS group). In conclusion, DTX, CTX and EPI induce liver damage in a dose dependent manner, whereas APS exerted protective effects.

Chitosan nanoparticles and quercetin modulate gene expression and prevent the genotoxicity of aflatoxin B1 in rat liver

The aims of the current study were to prepare chitosan nanoparticles (CNPs) and to evaluate its protective role alone or in combination with quercetin (Q) against AFB₁-induce cytotoxicity in rats. Male Sprague-Dawley rats were divided into 12 groups and treated orally for 4 weeks as follow: the control group, the group treated with AFB₁ (80 μg/kg b.w.) in corn oil, the groups treated with low (140 mg/kg b.w.) or high (280 mg/kg b.w.) dose of CNPs, the group treated with Q (50 mg/kg b.w.), the groups treated with Q plus the low or the high dose of CNPs and the groups treated with AFB₁ plus Q and/or CNPs at the two tested doses. The results also revealed that administration of AFB₁ resulted in a significant increase in serum cytokines, Procollagen III, Nitric Oxide, lipid peroxidation and DNA fragmentation accompanied with a significant decrease in GPx I and Cu–Zn SOD-mRNA gene expression. Q and/or CNPs at the two tested doses overcome these effects especially in the group treated with the high dose of CNPs plus Q. It could be concluded that CNPs is a promise candidate as drug delivery enhances the protective effect of Q against the cytogenetic effects of AFB₁ in high endemic areas.

Effects of antibiotic antitumor drugs on nucleotide levels in cultured tumor cells: an exploratory method to distinguish the mechanisms of antitumor drug action based on targeted metabolomics

Nucleotide pools in mammalian cells change due to the influence of antitumor drugs, which may help in evaluating the drug effect and understanding the mechanism of drug action. In this study, an ion-pair RP-HPLC method was used for a simple, sensitive and simultaneous determination of the levels of 12 nucleotides in mammalian cells treated with antibiotic antitumor drugs (daunorubicin, epirubicin and dactinomycin D). Through the use of this targeted metabolomics approach to find potential biomarkers, UTP and ATP were verified to be the most appropriate biomarkers. Moreover, a holistic statistical approach was put forward to develop a model which could distinguish 4 categories of drugs with different mechanisms of action. This model can be further validated by evaluating drugs with different mechanisms of action. This targeted metabolomics study may provide a novel approach to predict the mechanism of action of antitumor drugs.

Oxidative stress and brain mitochondria swelling induced by endosulfan and protective role of quercetin in rat

The neurological damages resulted by endosulfan poisoning is not completely elucidated, especially in cellular organelles such as mitochondria. In the present study, the pro-oxidant effect of endosulfan on brain mitochondria was first investigated. Gavages of endosulfan into rats at the dose of 2 mg/kg induced oxidative stress in this organelle since it provokes a significant reduction of catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) level. In addition, a significant increase in mitochondria swelling and malondialdehyde (MDA) levels were observed in neuronal mitochondria, indicating clearly an intense peroxidation within mitochondria. Second, the protective effect of quercetin (QE) (10 mg/kg) against endosulfan-induced oxidative stress in mitochondria was also assessed. Indeed, the pretreatment of rats with QE protects brain mitochondria from oxidative stress, lipid peroxidation, and mitochondria swelling induced by endosulfan. The activities of antioxidant enzymes and the mitochondrial content of GSH and MDA were returned to control values. Thus, although endosulfan can have neurotoxic effects in brain rats, this toxicity can be prevented by quercetin.

Differential protective effects of polyphenol extracts from apple peels and fleshes against acute CCl4-induced liver damage in mice

The present study reports the phenolic profiles and antioxidant and hepatoprotective properties of Red Fuji apple peel polyphenolic extract (APP) and its flesh polyphenolic extract (AFP) against CCl₄-induced acute hepatic damage in mice.

The flavonoid quercetin: possible solution for anthracycline-induced cardiotoxicity and multidrug resistance

Anthracycline chemotherapy is often used in the treatment of various malignancies. Its application, however, encounters several limitations due to development of serious side effects, mainly cardiotoxicity and may be ineffective due to multidrug resistance (MDR). Many different compounds have been evaluated as poorly effective in the protection against anthracycline side effects and in the prevention from MDR. Thus, continuous investigational efforts are necessary to find valuable protectants and the flavonoid quercetin (Q) seems to be a promising candidate. It is present in relatively high amounts in a human diet and the lack of its toxicity, including genotoxicity has been confirmed. The structure of Q favours its high antioxidant activity, the potential to inhibit the activity of oxidative enzymes and to interact with membrane transporter proteins responsible for development of MDR, e.g. P-glycoprotein. Furthermore, Q can influence cellular signalling and gene expression, and thus, alter response to exogenous genotoxicants and oxidative stress in normal cells. It accounts for its chemopreventive and anticancer properties. Overall, these properties might indicate the possibility of application of Q as cardioprotectant during anthracycline chemotherapy. Moreover, numerous biological properties displayed by Q might possibly result in the reversal of MDR in tumour cells and improve the efficacy of chemotherapy. However, these beneficial effects towards anthracycline-induced complications of chemotherapy have to be further explored and confirmed both in animal and clinical studies. Concurrently, investigations aimed at improvement of the bioavailability of Q and further elucidation of its metabolism after application in combination with anthracyclines are needed.

Studies on the effect of quercetin and nitrates on the redox homeostasis using in vitro model

Antioxidants are widely considered to be a preventive measure for many diseases and beneficial for health. However, an increasing number of reports suggest a lack of any influence by antioxidants on health or even harmful pro-oxidative effects of antioxidants. In most cases, the research was conducted with respect to a chosen antioxidant, without considering the presence of other chemical substances present in food, with which these compounds may react. The aim of this work was to determine whether and to what extent the simultaneous presence of quercetin and sodium nitrate influences oxidative-reductive homeostasis in fibroblast cultures. Superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), and nitric oxide synthase (NOS) activities were measured together with nitric oxide (NO) concentration and total antioxidant status (TAS). An increase in the activity of all the enzymes measured and in the NO concentration was determined compared with the control culture. The most prominent changes were observed at the highest quercetin concentration. These results indicate that the simultaneous presence of quercetin and sodium nitrate disrupts the oxidative-reductive homeostasis in fibroblasts.

Progesterone increases apoptosis and inversely decreases autophagy in human hepatoma HA22T/VGH cells treated with epirubicin

Hepatocellular carcinoma (HCC) is the leading cause of cancer-related deaths worldwide. Epirubicin can induce intracellular reactive oxygen species and is widely used to treat unresectable HCC. Progesterone has been found to inhibit the proliferation of hepatoma cells. This study was designed to test the combined effects of epirubicin and progesterone on human hepatoma cell line, HA22T/VGH. These cells were treated with different concentrations of epirubicin with or without the coaddition of 30 μM progesterone and then analyzed for apoptosis, autophagy, and expressions of apoptotic-related proteins and multidrug-resistant gene. Epirubicin treatment dose-dependently inhibited the growth of HA22T/VGH cells. Addition of 30 μM progesterone, which was inactive alone, augmented the effect of epirubicin on the inhibition of growth of HA22T/VGH cells. Cotreatment with progesterone enhanced epirubicin-induced apoptosis, as evidenced by greater increase in caspase-3 activity and in the ratio of the apoptosis-regulating protein, Bax/Bcl-X_L. The combination also caused a decrease in autophagy and in the expression of multidrug resistance-related protein 1 mRNA compared to epirubicin alone. This study shows the epirubicin/progesterone combination was more effective in increasing apoptosis and inversely decreasing autophagy on HA22T/VGH cells treated with epirubicin alone, suggesting that this combination can potentially be used to treat HCC.

Pro-oxidative and antioxidative controls and signaling modification of polyphenolic phytochemicals: contribution to health promotion and disease prevention?

Polyphenolic phytochemicals (PPs) have been extensively studied as potential nutriceuticals for maintenance of health and treatment of cancer, inflammation, and neurodegeneration. However, the reported beneficial outcomes are inconsistent. The biological activities of PPs have been attributed to their pro-oxidative and antioxidative actions and effects on signaling mechanisms and epigenomic modifications. These diversified properties were described or postulated on the basis of a variety of experimental studies using cell culture and animal models, even though most have not been replicated and results are not validated. This review attempts to give an overview of biological properties of PPs, based on the coherent results from relevant studies, and evaluate critically the experimental conditions and possible artifacts. Complicated molecular mechanisms and multitargeting genomic interactions of PPs are discussed, with a view that reasonable mechanistic propositions are usually obtained from well-designed in vivo studies.

The decrease of NAD(P)H:quinone oxidoreductase 1 activity and increase of ROS production by NADPH oxidases are early biomarkers in doxorubicin cardiotoxicity

CONTEXT

Doxorubicin cardiotoxicity displays a complex and multifactorial progression.

OBJECTIVE

Identify early biochemical mechanisms leading to a sustained imbalance of cellular bioenergetics.

METHODS

Measurements of the temporal evolution of selected biochemical markers after treatment of rats with doxorubicin (20 mg/kg body weight).

RESULTS

Doxorubicin treatment increased lipid oxidation, catalase activity and production of H₂O₂ by Nox-NADPH oxidases, and down-regulated

NAD(P)H

quinone oxidoreductase-1 prior eliciting changes in reduced glutathione, protein carbonyls and protein nitrotyrosines. Alterations of mitochondrial and myofibrillar bioenergetics biomarkers were detected only after this oxidative imbalance was established.

CONCLUSIONS

NAD(P)H

quinone oxidoreductase-1 activity and increase of hydrogen peroxide production by NADPH oxidases are early biomarkers in doxorubicin cardiotoxicity.

Effects of yam peel extract against carbon tetrachloride-induced hepatotoxicity in rats

The phenolic acid and flavonoid profiles in yam peel extract were determined by HPLC. Quercetin, hesperidin, and apigenin were predominant components in yam peel extract. Male Wistar rats were orally treated with yam peel extract (100.02, 266.72, and 433.42 mg/kg) or silymarin (200 mg/kg) daily, with administration of CCl4 (1 mL/kg, 20% CCl4 in olive oil) twice a week. Yam peel extract for 8 weeks significantly reduced the impact of CCl4 toxicity on the serum markers of liver damage, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). The overall potential of the antioxidant system was significantly enhanced by the yam peel extract supplements as the plasma and hepatic thiobarbituric acid reactive substances (TBARS) levels were lowered, whereas the hepatic superoxide dismutase (SOD) and catalase (CAT) activities and glutathione peroxidase (GSH-Px) protein level were elevated. Yam peel extract decreased the level of nitric oxide (NO) production, tumor necrosis factor-alpha (TNF-α), and nuclear factor-kappa B (NF-κB) in CCl4. These results point out that yam peel extract can inhibit lipid peroxidation, enhance the activities of antioxidant enzymes, and decrease the TNF-α/NF-κB level, nitric oxide production, and inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions. Therefore, it was speculated that yam peel extract protects rats from liver damage through its anti-inflammation capacity.

Mitochondria-mediated mitigatory role of curcumin in cisplatin-induced nephrotoxicity

Cisplatin (CP) is one of the most potent chemotherapeutic anti-tumour drugs, and it has been implicated in renal toxicity. Oxidative stress has been proven to be involved in CP-induced toxicity including nephrotoxicity. However, there is paucity of literature involving role of mitochondria in mediating CP-induced renal toxicity, and its underlying mechanism remains unclear. Therefore, the present study was undertaken to examine the antioxidant potential of curcumin (CMN; a natural polyphenolic compound) against the mitochondrial toxicity of CP in kidneys of male rats. Acute toxicity was induced by a single intra-peritoneal injection of CP (6 mg kg(-1) ). We studied the ameliorative effect of CMN pre-treatment (200 mg kg(-1) ) on the toxicity of CP in rat kidney mitochondria. CP caused a significant elevation in the mitochondrial lipid peroxidation (LPO) levels and protein carbonyl (PC) content. Pre-treatment of rat with CMN significantly replenished the mitochondrial LPO levels and PC content. It also restored the CP-induced modulatory effects on altered enzymatic and non-enzymatic antioxidants in kidney mitochondria. We hypothesize that the reno-protective effects of CMN may be related to its predisposition to scavenge free radicals, and upregulate antioxidant machinery in kidney mitochondria.

Quercetin potentiates doxorubicin mediated antitumor effects against liver cancer through p53/Bcl-xl

BACKGROUND

The dose-dependent toxicities of doxorubicin (DOX) limit its clinical applications, particularly in drug-resistant cancers, such as liver cancer. In this study, we investigated the role of quercetin on the antitumor effects of DOX on liver cancer cells and its ability to provide protection against DOX-mediated liver damage in mice.

METHODOLOGY AND RESULTS

The MTT and Annexin V/PI staining assay demonstrated that quercetin selectively sensitized DOX-induced cytotoxicity against liver cancer cells while protecting normal liver cells. The increase in DOX-mediated apoptosis in hepatoma cells by quercetin was p53-dependent and occurred by downregulating Bcl-xl expression. Z-VAD-fmk (caspase inhibitor), pifithrin-α (p53 inhibitor), or overexpressed Bcl-xl decreased the effects of quercetin on DOX-mediated apoptosis. The combined treatment of quercetin and DOX significantly reduced the growth of liver cancer xenografts in mice. Moreover, quercetin decreased the serum levels of alanine aminotransferase and aspartate aminotransferase that were increased in DOX-treated mice. Quercetin also reversed the DOX-induced pathological changes in mice livers.

CONCLUSION AND SIGNIFICANCE

These results indicate that quercetin potentiated the antitumor effects of DOX on liver cancer cells while protecting normal liver cells. Therefore, the development of quercetin may be beneficial in a combined treatment with DOX for increased therapeutic efficacy against liver cancer.

Effects of epirubicin on barley seedlings

Epirubicin (EPI) is one of the anthracycline antibiotics, which is used in cancer chemotherapy. It inhibits DNA and RNA synthesis and causes cell death by DNA cleavage and production of free radicals. In this study, phytotoxicity of EPI was investigated on root and shoot growth, antioxidant enzymes and retrotransposons’ movements in 10- and 20-day-old barley seedlings. Mature embryos of barley were germinated on Murashige and Skoog medium supplemented with 250 and 500 μg/ml EPI. Our results showed that EPI treatment significantly inhibited shoot and root growth when compared with control group. Treatment with 250 and 500 μg/ml of EPI reduced shoot length in the 10-day-old plants by approximately 1.5- and 2-fold, respectively; the same treatments reduced total root length by 2- and 4-folds, respectively. However, the shoot and root lengths of 20-day-old plants were observed to be more affected by EPI-treatment. A 500-μg/ml concentration decreased total protein levels and peroxidase (EC 1.11.1.11) activity and increased superoxide dismutase (EC 1.15.1.1) and catalase (EC 1.11.1.6) activities. To investigate the effect of EPI on the movements of BARE-1, SUKKULA and BAGY2 retrotransposons, inter-retrotransposon amplified polymorphism technique was performed. While some polymorphic polymerase chain reaction bands were observed for BARE-1, no polymorphism was identified in SUKKULA and BAGY2 movements. To our knowledge, this is the first report showing phytotoxic effects of EPI on plant germination and retrotransposons’ movements.

Chemical composition and hepatoprotective effects of polyphenol-rich extract from Houttuynia cordata tea

This study was designed to investigate the antioxidant activity, hepatoprotective effect, and phenolic composition of the ethyl acetate fraction (EAF) extracted from Houttuynia cordata tea. EAF was shown to exhibit strong ferric-reducing antioxidant power (FRAP) and scavenging activity against DPPH radical in vitro, and the antioxidant effects were further verified by suppressing CCl₄-induced oxidative stress in mouse liver at three tested doses of EAF (250, 500, and 1000 mg/kg bw). Pretreatment with EAF (1000 mg/kg bw) prior to CCl₄ administration significantly (p < 0.001) decreased the CCl₄-elevated levels of serum AST, ALT, alkaline phosphatase, total bilirubin, and hepatic MDA in mice and prevented the increases in GSH, SOD, and CAT caused by CCl₄. HPLC analysis revealed that three predominantly polyphenolic compounds present in EAF were quercitrin (111.7 μg/mg), quercetin (43.8 μg/mg), and hyperoside (29.1 μg/mg). These results combined with liver histopathology indicate that EAF possesses a significant protective effect against acute hepatotoxicity induced by CCl₄, which may be due to the strong antioxidant activity of phenolic components.

Evaluation of destructive effects of exposure to cisplatin during developmental stage: no profound evidence for sex differences in impaired motor and memory performance

We have elucidated the alteration in hippocampal and cerebellum function following chronic cisplatin treatment in male and female rats. Hippocampus and cerebellum related behavioral dysfunction in cisplatin-treated [intraperitoneally, 5 mg/(kg/week) for 5 weeks from 23-day-old] rats were analyzed using explorative, motor function, learning, and memory tasks (grasping, rotarod, open field, and Morris water maze tests). Exposure to cisplatin impaired the motor coordination in male and female rats. Exposure to cisplatin was reflected by a decrease in grasping time compared to vehicle-treated controls (saline) only in male rat while there were not any differences in female rats. When the rearing frequency, total distance moved and velocity of their recorded in open fieldtest, both males and females were dramatically affected by exposure to cisplatin. Compared to the saline, male and female rats trained 5 weeks after cisplatin injection showed significant memory deficits in the Morris water maze test. However, hippocampal and cerebellum functions of male and female rats were profoundly affected by exposure to cisplatin while no sex differences in the most variable were evident.

GRP78 knockdown enhances apoptosis via the down-regulation of oxidative stress and Akt pathway after epirubicin treatment in colon cancer DLD-1 cells

INTRODUCTION

The 78-kDa glucose-regulated protein (GRP78) is induced in the cancer microenvironment and can be considered as a novel predictor of responsiveness to chemotherapy in many cancers. In this study, we found that intracellular reactive oxygen species (ROS) and nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation were higher in GRP78 knockdown DLD-1 colon cancer cells compared with scrambled control cells.

METHODOLOGY/PRINCIPAL FINDINGS

Treatment with epirubicin in GRP78 knockdown DLD-1 cells enhanced apoptosis and was associated with decreased production of intracellular ROS. In addition, apoptosis was increased by the antioxidants propyl gallate (PG) and dithiothreitol (DTT) in epirubicin-treated scrambled control cells. Epirubicin-treated GRP78 knockdown cells resulted in more inactivated Akt pathway members, such as phosphorylated Akt and GSK-3β, as well as downstream targets of β-catenin expression. Knockdown of Nrf2 with small interfering RNA (siRNA) increased apoptosis in epirubicin-treated GRP78 knockdown cells, which suggested that Nrf2 may be a primary defense mechanism in GRP78 knockdown cells. We also demonstrated that epirubicin-treated GRP78 knockdown cells could decrease survival pathway signaling through the redox activation of protein phosphatase 2A (PP2A), which is a serine/threonine phosphatase that negatively regulates the Akt pathway.

CONCLUSIONS

Our results indicate that epirubicin decreased the intracellular ROS in GRP78 knockdown cells, which decreased survival signaling through both the Akt pathway and the activation of PP2A. Together, these mechanisms contributed to the enhanced level of epirubicin-induced apoptosis that was observed in the GRP78 knockdown cells.

Profound destructive effects of adolescent exposure to vincristine accompanied with some sex differences in motor and memory performance

Vincristine, an anticancer drug, is known to induce neuronal cell damage. We have elucidated the alteration in performance of the hippocampus and cerebellum following chronic vincristine treatment (0.2 mg·(kg body mass)–1·week–1) in male and female rats. Intraperitoneal injection of vincristine in adolescent rats caused impairment of motor and cognitive behavior. In the probe test, the length of path traveled and percent swimming time for vincristine-treated rats in the correct quadrant was significantly less than for the saline-treated (control) groups. The path length and time latency at the 2nd and 3rd blocks of trials for the male vincristine-treated group was significantly higher than that for the female saline- and the vincristine-treated rats. In the rod test, vincristine exposure impaired the motor coordination in both male and female rats. Exposure to vincristine caused a significant decrease in hanging time in male rats, compared with the saline- and the vincristine-treated female rats, while there were no differences between the female vincristine-treated rats and the saline-treated rats of both sexes. The rearing frequency, total distance moved, and velocity for both male and female rats were dramatically affected by exposure to vincristine. We have observed that the hippocampal and cerebellar functions of male and female rats were profoundly affected by exposure to vincristine, especially the male rats, suggesting a sexual dimorphism in the developing central nervous system that is affected by chemicals such as anticancer drugs.

Quercetin prevents ethanol-induced dyslipidemia and mitochondrial oxidative damage

Lipid metabolism disorder and oxidative stress play an important role on the development and progression of alcoholic liver disease (ALD), and mitochondria compartment is presumed as the main source and susceptible target of intracellular ROS. The objective of this study was to evaluate the protective effect of quercetin, a naturally occurring flavonoids possessing both antioxidant and hypolipidemic effect, on ethanol-induced dyslipidemia and oxidative damage focused on mitochondria. Chronic alcohol administration for adult male rats (4.0 g/kg for 90 days) resulted in the leakage of alanine and especially aspartate aminotransferases, and morphological malformation mainly evidenced by sustained lipid infiltration and degenerative changes on mitochondria and rough endoplasmic reticulum, which was markedly alleviated by quercetin (100 mg/kg.bw.) pretreatment. Furthermore, quercetin prophylaxis evidently ameliorated ethanol-stimulated mitochondrial dysfunction manifested by decreased membrane potential and induced permeability transition though suppressing glutathione depletion, enzymatic inactivation of manganese superoxide dismutase and glutathione peroxidase, ROS over-generation, and lipid peroxidation in mitochondria. Quercetin, thus, may protect rat, especially hepatic mitochondria, from chronic ethanol toxicity through its hypolipidemic effect and antioxidative role, highlighting a promising preventive strategy for ALD by naturally occurring phytochemicals.

Chemotherapy-induced weakness and fatigue in skeletal muscle: the role of oxidative stress

SIGNIFICANCE

Fatigue is one of the most common symptoms of cancer and its treatment, manifested in the clinic through weakness and exercise intolerance. These side effects not only compromise patient's quality of life (QOL), but also diminish physical activity, resulting in limited treatment and increased morbidity.

RECENT ADVANCES

Oxidative stress, mediated by cancer or chemotherapeutic agents, is an underlying mechanism of the drug-induced toxicity. Nontargeted tissues, such as striated muscle, are severely affected by oxidative stress during chemotherapy, leading to toxicity and dysfunction.

CRITICAL ISSUES

These findings highlight the importance of investigating clinically applicable interventions to alleviate the debilitating side effects. This article discusses the clinically available chemotherapy drugs that cause fatigue and oxidative stress in cancer patients, with an in-depth focus on the anthracycline doxorubicin. Doxorubicin, an effective anticancer drug, is a primary example of how chemotherapeutic agents disrupt striated muscle function through oxidative stress.

FUTURE DIRECTIONS

Further research investigating antioxidants could provide relief for cancer patients from debilitating muscle weakness, leading to improved quality of life.

Quercetin protects rat liver against lead-induced oxidative stress and apoptosis

Quercetin, a flavonoid, effectively improved the lead-induced histology changes including structure damage and leukocyte infiltration in rat liver. The present study was designed to explore the protective mechanism of quercetin against lead-induced hepatic injury. We found that quercetin markedly decreased the MDA and H(2)O(2) levels and lowered the GSH/GSSG ratio in the liver of lead-treated rat. Moreover, quercetin markedly restored Cu/Zn-SOD, Mn-SOD, CAT and GPx activities and upregulated mRNA expression levels of these proteins in the liver of lead-treated rat. Western blot analysis showed that quercetin significantly inhibited apoptosis by modulating the ratio of Bax to Bcl-2 expression and suppressing the expression of phosphorylated JNK1/2 and cleaved caspase-3 in the liver of lead-treated rat. In conclusion, these data suggest that quercetin protects the rat liver from lead-induced injury by attenuating lipid peroxidation, renewing the activities of antioxidant enzymes and inhibiting apoptosis.