Crocin Abrogates Carbon Tetrachloride‐Induced Renal Toxicity in Rats via Modulation of Metabolizing Enzymes and Diminution of Oxidative Stress,Apoptosis, and Inflammatory Cytokines

This work aimed at investigating the potential modulatory effects and mechanisms of crocin against CCl₄‐induced nephrotoxicity. Forty male rats were allocated for three weeks treatment with corn oil, CCl₄, crocin, or crocin plus CCl₄. Crocin effectively mitigated CCl₄‐induced kidney injury as evidenced by amelioration of alterations in kidney histopathology, renal weight/100 g body weight ratio and kidney functions. Crocin modulated CCl₄‐induced disturbance of kidney cytochrom‐P450 subfamily 2E1 and glutathione‐S‐transferase. The attenuation of crocin to kidney injury was also associated with suppression of oxidative stress via reduction of lipid peroxides along with induction of renal glutathione content and enhancement of superoxide dismutase, glutathione peroxidase, and catalase activities. Crocin mitigated CCl₄‐induced elevation of the renal levels of tumor necrosis factor‐alpha, interleukin‐6, prostaglandin E2, and active caspases‐3. Collectively, crocin alleviated CCl₄‐induced renal damage via modulation of kidney metabolizing enzymes, suppression of oxidative stress, inhibition of inflammatory cytokines, PGE2, and active caspase3 in kidney.     

Guanosine protects C6 astroglial cells against azide‐induced oxidative damage: a putative role of heme oxygenase 1

Guanosine, a guanine‐based purine, is an extracellular signaling molecule that is released from astrocytes and shows neuroprotective effects in several in vivo and in vitro studies. Our group recently showed that guanosine presents antioxidant properties in C6 astroglial cells. The heme oxygenase 1 signaling pathway is associated with protection against oxidative stress. Azide, an inhibitor of the respiratory chain, is frequently used in experimental models to induce oxidative and nitrosative stress. Thus, the goal of this study was to investigate the effect of guanosine on azide‐induced oxidative damage in C6 astroglial cells. Azide treatment of these cells resulted in several detrimental effects, including induction of cytotoxicity and mitochondrial dysfunction, increased levels of reactive oxygen/nitrogen species, inducible nitric oxide synthase expression and NADPH oxidase, decreased glutamate uptake and EAAC1 glutamate transporter expression, decreased glutathione (GSH) levels, and decreased activities of glutamine synthetase (GS), superoxide dismutase and catalase (CAT). The treatment also increased nuclear factor‐κB activation and the release of proinflammatory cytokines tumor necrosis factor α and IL‐1β. Guanosine strongly prevented these effects, protecting glial cells against azide‐induced cytotoxicity and modulating glial, oxidative and inflammatory responses through the activation of the heme oxygenase 1 pathway. These observations reinforce and support the role of guanosine as an antioxidant molecule against oxidative damage.

     

Protective Effects of Anthocyanins from Coreopsis tinctoria against Oxidative Stress Induced by Hydrogen Peroxide in MIN6 Cells

Anthocyanins (AC) from Coreopsis tinctoria possesses strong antioxidant properties, while the effects of AC on cells damage induced by reactive oxygen species (ROS) in diabetes mellitus diseases progression have not been reported. The present study was carried out to evaluate the protective property of AC against cellular oxidative stress with an experimental model, H₂O₂‐exposed MIN6 cells. AC could reverse the decrease of cell viability induced by H₂O₂ and efficiently suppressed cellular ROS production and cell apoptosis. In addition, Real‐time PCR and Western blot analyses indicated that AC could protect MIN6 cells against oxidative injury through increasing the translocation of Nrf2 into nuclear, decreasing the phosphorylation level of p38 and up‐regulating the protein expression of antioxidant enzyme (SOD1, SOD2 and CAT). Thus, this study provides evidence to support the beneficial effect of AC in inhibiting MIN6 cells from H₂O₂‐induced oxidative injury.     

Prophylactic role of taurine on arsenic mediated oxidative renal dysfunction via MAPKs/ NF-κB and mitochondria dependent pathways

The present study has been designed and carried out to investigate the protective role of taurine (2-aminoethanesulphonic acid) against NaAsO₂ induced nephrotoxicity. Oral administration of arsenic increased the productions of ROS and RNS, enhanced lipid peroxidation, protein carbonylation and decreased intracellular antioxidant defence in the kidney tissue. Investigating the responsible signalling cascades, it was found that NaAsO₂ administration activates mitogen-activated protein kinases (MAPKs) and NF-κB in oxidative stress mediated renal dysfunction and induced apoptotic cell death by the reciprocal regulation of Bcl-2/Bad in association with reducing mitochondrial membrane potential and increased cytosolic cytochrome C as well. Treatment with taurine prior to arsenic administration effectively ameliorated As-induced oxidative renal dysfunctions and apoptotic cell death. Histological studies also support the experimental findings. Combining, results suggest that taurine possesses the ability to ameliorate arsenic-induced oxidative insult and renal damage, probably due to its antioxidant activity and functioning via MAPKs/NF-κB and mitochondria dependent pathways.     

The protective effect of a purified extract of <Emphasis Type="Italic">Withania somnifera</Emphasis> against doxorubicin-induced cardiac toxicity in rats

The therapeutic value of doxorubicin as an effective antineoplastic agent is limited by its cardiotoxic side-effects. The administration of doxorubicin (10 mg/kg) to male Wistar rats induced necrosis and apoptosis in heart tissues. It also caused oxidative stress damage as evidenced by the elevation of malondialdehyde and protein carbonyl levels and catalase activity, accompanied by the concurrent depletion of total antioxidant capacity and of superoxide dismutase level in cardiac tissues. The doxorubicin-induced cardiotoxicity and oxidative stress damage were also accompanied by increases of myeloperoxidase activity, total calcium content, and the expression of Bcl-2 protein in heart tissues. Most of these doxorubicin-induced biochemical and histological alterations were effectively attenuated by prior administration of purified standardized extract (1.5% withanolides; manufactured by Idea Sphere Inc., American Fork, UT, USA) of Withania somnifera (300 mg/kg). Thus, Withania may play a role in the protection against cardiotoxicity and thus might be a useful adjuvant therapy where doxorubicin is the cancer-treating drug.     

Neuroprotective Effects of Butanol Fraction of Cordyceps cicadae on Glutamate‐Induced Damage in PC12 Cells Involving Oxidative Toxicity

The current study was aimed at investigating the neuroprotective effects of the butanol fraction from Cordyceps cicadae (C_BU), which was responsible for the anti‐aging effect of this medicine. Glutamate‐induced PC12 cells were used as a model to determine the neuroprotective effect against oxidative cell death. Cell viability, cytotoxicity, flow cytometry, mitochondrial transmembrane potential (MMP), reactive oxygen species (ROS), glutathione peroxidase (GSH‐Px), and superoxide dismutase (SOD) levels were analyzed to assess neuronal cell survival or death. The results obtained from the above evaluations showed that C_BU was the most effective fraction and even better than pure compounds present in C. cicadae in terms of suppressing glutamate‐induced damage in PC12 cells, increasing cell viability, decreasing lactase dehydrogenase (LDH) release, and reduction of apoptosis induced by exposure to glutamate. Furthermore, C_BU protected cells against mitochondrial dysfunction and oxidative stress as indicated by the suppression of ROS accumulation and up regulation of the levels of GSH‐Px and SOD. In summary, the above results showed that C_BU exerted neuroprotective effect against oxidative damage, and this activity could be partly due to the action of nucleosides present in the C_BU.     

Acute treatment with relaxin protects the kidney against ischaemia/reperfusion injury

Although recent preclinical and clinical studies have demonstrated that recombinant human relaxin (rhRLX) may have important therapeutic potential in acute heart failure and chronic kidney diseases, the effects of acute rhRLX administration against renal ischaemia/reperfusion (I/R) injury have never been investigated. Using a rat model of 1‐hr bilateral renal artery occlusion followed by 6‐hr reperfusion, we investigated the effects of rhRLX (5 μg/Kg i.v.) given both at the beginning and after 3 hrs of reperfusion. Acute rhRLX administration attenuated the functional renal injury (increase in serum urea and creatinine), glomerular dysfunction (decrease in creatinine clearance) and tubular dysfunction (increase in urinary excretion of N‐acetyl‐β‐glucosaminidase) evoked by renal I/R. These beneficial effects were accompanied by a significant reduction in local lipid peroxidation, free radical‐induced DNA damage and increase in the expression/activity of the endogenous antioxidant enzymes Mn‐ and CuZn‐superoxide dismutases (SOD). Furthermore, rhRLX administration attenuated the increase in leucocyte activation, as suggested by inhibition of myeloperoxidase activity, intercellular‐adhesion‐molecule‐1 expression, interleukin (IL)‐1β, IL‐18 and tumour necrosis factor‐α production as well as increase in IL‐10 production. Interestingly, the reduced oxidative stress status and neutrophil activation here reported were associated with rhRLX‐induced activation of endothelial nitric oxide synthase and up‐regulation of inducible nitric oxide synthase, possibly secondary to activation of Akt and the extracellular signal‐regulated protein kinase (ERK) 1/2, respectively. Thus, we report herein that rhRLX protects the kidney against I/R injury by a mechanism that involves changes in nitric oxide signalling pathway.     

Protective effect of aminoguanidine against oxidative stress and bladder injury in cyclophosphamide‐induced hemorrhagic cystitis in rat

Cyclophosphamide (CP) is an antineoplastic agent that is used for the treatment of many neoplastic diseases. Hemorrhagic cystitis (HC) is a major dose limiting side effect of CP. Recent studies show that aminogaunidine, an inhibitor of inducible nitric oxide synthase is a potent antioxidant and prevents changes caused by oxidative stress such as depletion of antioxidant activity and tissue injury. The purpose of the study is to investigate the effect of aminoguanidine on parameters of oxidative stress, antioxidant enzymes and bladder injury caused by CP. Adult male rats were randomly divided into four groups. Control rats were administered saline; the AG control group received 200 mg/kg body wt of aminoguanidine; The CP group received a single injection of CP at the dose of 150 mg/kg body wt intraperitoneally. The CP + AG group received aminoguanidine (200 mg/kg body wt) intraperitoneally 1 h before the administration of CP. The rats were sacrificed 16 h after CP/saline administration. The bladder was used for light microscopic studies and biochemical studies. The markers of oxidative damage including protein carbonyl content, protein thiol, malondialdehyde and conjugated dienes were assayed in the homogenates along with the activities of the antioxidant enzymes, superoxide dismutase, glutathione peroxidase, catalase, and glutathione reductase and glutathione S transferase. In the bladders of CP treated rats edema of lamina propria with epithelial and sub‐epithelial hemorrhage was seen. All the parameters of oxidative stress that were studied were significantly elevated in the bladders of CP treated rats. The activities of the antioxidant enzymes were significantly lowered in the bladders of CP treated rats. Aminoguanidine pretreatment prevented CP‐induced oxidative stress, decrease in the activities of anti‐oxidant enzymes and reduced bladder damage. The results of the present study suggest the antioxidant role for aminoguanidine in CP‐induced bladder damage. Copyright © 2008 John Wiley & Sons, Ltd.     

Propensity of crocin to offset Vipera russelli venom induced oxidative stress mediated neutrophil apoptosis: a biochemical insight

Viper envenomation results in inflammation at the bitten site as well as target organs. Neutrophils and other polymorphonuclear leukocytes execute inflammation resolving mechanism and will undergo apoptosis after completing the task. However, the target specific toxins induce neutrophil apoptosis at the bitten site and in circulation prior to their function, thus reducing their number. Circulating activated neutrophils are major source of inflammatory cytokines and leakage of reactive oxygen species (ROS)/other toxic intermediates resulting in aggravation of inflammatory response at the bitten/target site. Therefore, neutralization of venom induced neutrophil apoptosis reduces inflammation besides increasing the functional neutrophil population. Therefore, the present study investigates the venom induced perturbances in isolated human neutrophils and its neutralization by crocin (Crocus sativus) a potent antioxidant carotenoid. Human neutrophils on treatment with venom resulted in altered ROS generation, intracellular Ca²⁺ mobilization, mitochondrial membrane depolarization, cyt-c translocation, caspase activation, phosphatidylserine externalization and DNA damage. On the other hand significant protection against oxidative stress and apoptosis were evidenced in crocin pre-treated groups. In conclusion the viper venom induces neutrophil apoptosis and results in aggravation of inflammation and tissue damage. The present study demands the necessity of an auxiliary therapy in addition to antivenin therapy to treat secondary/overlooked complications of envenomation.     

Hydrogen gas inhalation protects against cutaneous ischaemia/reperfusion injury in a mouse model of pressure ulcer

Pressure ulcer formation depends on various factors among which repetitive ischaemia/reperfusion(I/R) injury plays a vital role. Molecular hydrogen (H₂) was reported to have protective effects on I/R injuries of various internal organs. In this study, we investigated the effects of H₂ inhalation on pressure ulcer and the underlying mechanisms. H₂ inhalation significantly reduced wound area, 8‐oxo‐dG level (oxidative DNA damage) and cell apoptosis rates in skin lesions. H₂ remarkably decreased ROS accumulation and enhanced antioxidant enzymes activities by up‐regulating expression of Nrf2 and its downstream components in wound tissue and/or H₂O₂‐treated endothelia. Meanwhile, H₂ inhibited the overexpression of MCP‐1, E‐selectin, P‐selectin and ICAM‐1 in oxidant‐induced endothelia and reduced inflammatory cells infiltration and proinflammatory cytokines (TNF‐α, IL‐1, IL‐6 and IL‐8) production in the wound. Furthermore, H₂ promoted the expression of pro‐healing factors (IL‐22, TGF‐β, VEGF and IGF1) and inhibited the production of MMP9 in wound tissue in parallel with acceleration of cutaneous collagen synthesis. Taken together, these data indicated that H₂ inhalation suppressed the formation of pressure ulcer in a mouse model. Molecular hydrogen has potentials as a novel and alternative therapy for severe pressure ulcer. The therapeutic effects of molecular hydrogen might be related to its antioxidant, anti‐inflammatory, pro‐healing actions.     

Ginkgo biloba extract protects human melanocytes from H2O2‐induced oxidative stress by activating Nrf2

Vitiligo is a common skin depigmenting disorder characterized by the loss of functional melanocytes. Its pathogenesis is complicated and oxidative stress plays a critical role in the development of vitiligo. Thus, antioxidant therapy is a promising therapeutic strategy to prevent or even reverse the progression of depigmentation. Ginkgo biloba extract EGb761 has been confirmed to have protective effects on neurons against oxidative stress. Notably, several clinical trials have shown that patients with stable vitiligo achieved repigmentation after taking EGb761. However, the exact mechanism underlying the protective effects of EGb761 on melanocytes against oxidative stress has not been fully elucidated. In the present study, we found that EGb761 effectively protected melanocytes against oxidative stress‐induced apoptosis and alleviated the excessive accumulation of reactive oxygen species (ROS) and lipid peroxidation by enhancing the activity of antioxidative enzymes. Furthermore, the antioxidative effect of EGb761 was achieved by activating Nrf2 and its downstream antioxidative genes. In addition, interfering Nrf2 with siRNA abolished the protective effects of EGb761 on melanocytes against oxidative damage. In conclusion, our study proves that EGb761 could protect melanocytes from H₂O₂‐induced oxidative stress by activating Nrf2. Therefore, EGb761 is supposed to be a potential therapeutic agent for vitiligo.     

HPLC‐DAD Analysis,Antioxidant and Protective Effects of Tunisian Rhanterium suaveolens against Acetamiprid Induced Oxidative Stress on Mice Erythrocytes

The present study was performed to assess the HPLC‐DAD analysis as well as antioxidant and protective effects of Tunisian Rhanterium suaveolens (Rs) against acetamiprid (ACT) induced oxidative stress on mice erythrocytes. The in vitro assays showed that the methanolic extract of Rs has an impressive antioxidant effect proved by testing the total antioxidant and scavenging activities using BCB, DPPH and ABTS assays, respectively. Moreover, qualitative and quantitative analysis using HPLC‐DAD revealed the richness of Rs in polyphenols where p‐Coumaric, Apigenin‐7‐glucoside and Ferulic acid were detected as the most abundant polyphenols. In the in vivo experiment, ACT, used as a toxicity model, was given to mice at a dose of 20 mg/kg. The latter was the origin of hemolytic anemia characterized by a significant decrease in red blood cells, hemoglobin and hematocrit levels and an increase in bilirubin, LDH, osmotic fragility, reticulocytes and white blood cells number. Characteristic erythrocyte morphological alterations were also determined as spherocytosis, schistocytosis and dacryocystitis. The oxidative status of ACT‐treated mice was also altered manifested by a significant increase in MDA and GSH levels and a decrease in SOD, CAT and GPx activities. When receiving the Rs methanolic extract at a dose of 300 mg/kg, all the parameters cited above were restored in mice. These remarkable corrections could only confirm the important antioxidant effect and the noticeable protective properties that possess Rs owing to its broad range of secondary bioactive metabolites.     

Platelet-rich plasma ameliorates neurotoxicity induced by silver nanoparticles in male rats via modulation of apoptosis,inflammation, and oxidative stress

The widespread use of silver in various forms raises concerns about its potential adverse effects. Silver nanoparticles (AgNPs) can enter the brain and subsequently induce neurotoxicity. As a source of diverse growth factors and for its cytoprotective properties, platelet-rich plasma (PRP) has received considerable attention in regenerative medicine. Our aim was to estimate the toxic effects of AgNPs on the rat brain and assess the possible protective effects of PRP against AgNPs induced neurotoxicity. A total of 40 adult male rats were divided into four groups (n = 10), namely the control, AgNPs, AgNPs+PRP, and auto-recovery groups. AgNPs were given intraperitoneally (i.p.) at a 10 mg/kg dose.bw daily for 28 days. PRP was given (a day after AgNPs treatment) i.p. at a dose of 0.5 mL/kg.bw twice weekly for 3 weeks. Rats in the auto-recovery group were left without treatment for 3 weeks after AgNP toxicity. Serum and brain tissue samples were collected for assessment of proinflammatory cytokines, oxidative stress markers, as well as the expression levels of apoptotic markers. Brain histopathological and immunohistochemistry examinations were done. AgNPs significantly increased oxidative stress markers and proinflammatory cytokines, decreased antioxidant defense markers, and induced apoptosis and histopathological brain injuries. However, PRP treatment restored brain oxidant/antioxidant balance, attenuated the inflammatory state, prevented apoptosis, and improved the brain histopathological lesions induced by AgNPs, with no significant improvements shown by auto-recovery group. Our data provided a novel protective effect for PRP against AgNPs-induced neurotoxicity due to its antioxidant, anti-inflammatory, and antiapoptotic effects.     

Moderate O3/O2 therapy enhances enzymatic and non-enzymatic antioxidant in brain and cochlear that protects noise-induced hearing loss

Mitochondrial damage and oxidative stress are known to contribute to the pathogenesis of noise-induced hearing loss (NIHL). In this study, we examined the protective effect of O₂/O₃ mixture (ozone/oxygen) therapy against mitochondrial induced damage and oxidative stress by noise exposure in rat brain and cochlear. For this purpose, rats were divided into four groups: 1 – control group; 2 – noise-exposed group (100?dB); 3 – noise?+?O₂/O₃, and 4 – O₂/O₃ (30 µg/ml). After 14 d, animals were anesthetised. Rat brain and cochlear tissue were removed for evaluation of the histopathological damages, oxidative stress, and mitochondrial dysfunction in both tissues. Our findings indicated that noise caused pathological damage, oxidative stress, and mitochondrial dysfunction in rat brain and cochlear. Also, daily administration of an O₂/O₃ therapy (30 µg/ml intravenous) efficiently increased enzymatic and non-enzymatic antioxidant in brain and cochlear that this action led to inhibition of pathological damages, oxidative stress, reactive oxygen species formation, mitochondrial membrane potential (MMP) collapse, mitochondrial swelling, and cytochrome c release resulting from noise. These findings suggest that the moderate O₂/O₃ therapy enhances the capacity of enzymatic and non-enzymatic antioxidant in brain and cochlear that protects against NIHL.     

Effect of Terminalia chebula aqueous extract on oxidative stress and antioxidant status in the liver and kidney of young and aged rats

We evaluated the preventive effects of Terminalia chebula (T. chebula) aqueous extract on oxidative and antioxidative status in liver and kidney of aged rats compared to young albino rats. The concentrations of malondialdehyde (MDA), lipofuscin (LF), protein carbonyls (PCO), activities of xantione oxidase (XO), manganese‐superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione‐S‐transferase (GST), and glucose‐6‐phosphate dehydrogenase (G6PDH), levels of glutathione (GSH), vitamin C and vitamin E were used as biomarkers. In the liver and kidney of aged animals, enhanced oxidative stress was accompanied by compromised antioxidant defences. Administration of aqueous extract of T. cheubla effectively modulated oxidative stress and enhanced antioxidant status in the liver and kidney of aged rats. The results of the present study demonstrate that aqueous extract of T. cheubla inhibits the development of age‐induced damages by protecting against oxidative stress. Copyright © 2009 John Wiley & Sons, Ltd.     

Collagen peptide modified carboxymethyl cellulose as both antioxidant drug and carrier for drug delivery against retinal ischaemia/reperfusion injury

Oxidative stress can cause injury in retinal endothelial cells. Carboxymethyl cellulose modified with collagen peptide (CMCC) is of a distinct antioxidant capacity and potentially a good drug carrier. In this study, the protective effects of CMCC against H₂O₂‐induced injury of primary retinal endothelial cells were investigated. In vitro, we demonstrated that CMCC significantly promoted viability of H₂O₂‐treated cells, efficiently restrained cellular reactive oxygen species (ROS) production and cell apoptosis. Then, the CMCC was employed as both drug and anti‐inflammatory drug carrier for treatment of retinal ischaemia/reperfusion (I/R) in rats. Animals were treated with CMCC or interleukin‐10‐loaded CMCC (IL‐10@CMCC), respectively. In comparisons, the IL‐10@CMCC treatment exhibited superior therapeutic effects, including better restoration of retinal structural thickness and less retinal apoptosis. Also, chemiluminescence demonstrated that transplantation of IL‐10@CMCC markedly reduced the retinal oxidative stress level compared with CMCC alone and potently recovered the activities of typical antioxidant enzymes, SOD and CAT. Therefore, it could be concluded that CMCC provides a promising platform to enhance the drug‐based therapy for I/R‐related retinal injury.     

Phytochemical and Biological Characterization of Methanolic Extracts from Rumex algeriensis and Rumex tunetanus

The present study is aimed at the evaluation of the phytochemical profile and the biochemical properties of methanolic extracts obtained from different parts of Rumex algeriensis and Rumex tunetanus, two relict species limited to the North Africa. Phytochemical analyses of these extracts were performed using standard colorimetric procedures, HPLC‐DAD, and HPLC‐DAD‐ESI/MS, and their antioxidant/free radical scavenging capability was estimated through several in vitro cell‐free assays. Moreover, the anti‐inflammatory potential of these extracts was demonstrated in an in vitro model of acute intestinal inflammation using differentiated Caco‐2 cells. The results showed that all the extracts appeared endowed with excellent antioxidant/free radical scavenging properties. In particular, the extracts from both R. algeriensis and R. tunetanus flowers, and that from R. algeriensis stems were characterized by a remarkable SOD‐like and NO‐scavenging activity, as well as by the capability to protect albumin against HClO‐induced degradation. Furthermore, the extracts from flowers of both Rumex species, as well as R. algeriensis stems, showed an anti‐inflammatory effect in intestinal epithelial cells, as demonstrated by the inhibition of TNF‐α‐induced gene expression of IL‐6 and IL‐8. In conclusion, R. algeriensis and R. tunetanus have shown to be potential sources of bioactive products to be used in the prevention and treatment of pathologies related to oxidative stress and inflammation.     

Water-soluble fractions from defatted sesame seeds protect human neuroblast cells against peroxyl radicals and hydrogen peroxide-induced oxidative stress

Oxidative stress is involved in the development of aging-related diseases, such as neurodegenerative diseases. Dietary antioxidants that can protect neuronal cells from oxidative damage play an important role in preventing such diseases. Previously, we reported that water-soluble fractions purified from defatted sesame seed flour exhibit good antioxidant activity in vitro. In the present study, we investigated the protective effects of white and gold sesame seed water-soluble fractions (WS-wsf and GS-wsf, respectively) against 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) and hydrogen peroxide (H₂O₂) induced oxidative stress in human neuroblast SH-SY5Y cells. Pretreatment with WS-wsf and GS-wsf did not protect cells against AAPH-induced cytotoxicity, while simultaneous co-treatment with AAPH significantly improved cell viability and inhibited membrane lipid peroxidation. These results suggest that WS-wsf and GS-wsf protect cells from AAPH-induced extracellular oxidative damage via direct scavenging of peroxyl radicals. When oxidative stress was induced by H₂O₂, pretreatment WS-wsf and GS-wsf significantly enhanced cell viability. These results suggest that in addition to radical scavenging, WS-wsf and GS-wsf enhance cellular resistance to intracellular oxidative stress by activation of the Nrf-2/ARE pathway as confirmed by the increased Nrf2 protein level in the nucleus and increased heme oxygenase 1 (HO-1) mRNA expression. The roles of ferulic and vanillic acids as bioactive antioxidants in these fractions were also confirmed. In conclusion, our results indicated that WS-wsf and GS-wsf, which showed antioxidant activity in vitro, are also efficient antioxidants in a cell system protecting SH-SY5Y cells against both extracellular and intracellular oxidative stress.     

Striatal Protection in nNOS Knock-Out Mice After Quinolinic Acid-Induced Oxidative Damage

Under pathological conditions, nitric oxide can become a mediator of oxidative cellular damage, generating an unbalance between oxidant and antioxidant systems. The participation of neuronal nitric oxide synthase (nNOS) in the neurodegeneration mechanism has been reported; the activation of N-methyl-d-aspartate (NMDA) receptors by agonist quinolinic acid (QUIN) triggers an increase in nNOS function and promotes oxidative stress. The aim of the present work was to elucidate the participation of nNOS in QUIN-induced oxidative stress in knock-out mice (nNOS?/?). To do so, we microinjected saline solution or QUIN in the striatum of wild-type (nNOS +/+), heterozygote (nNOS+/?), and knock-out (nNOS?/?) mice, and measured circling behavior, GABA content levels, oxidative stress, and NOS expression and activity. We found that the absence of nNOS provides a protection against striatal oxidative damage induced by QUIN, resulting in decreased circling behavior, oxidative stress, and a partial protection reflected in GABA depletion. We have shown that nNOS-derived NO is involved in neurological damage induced by oxidative stress in a QUIN-excitotoxic model.