Peroxide-induced Cell Damage Research Articles

Protection of high-frequency low-intensity pulsed electric fields and brain-derived neurotrophic factor for SH-SY5Y cells against hydrogen peroxide-induced cell damage.

Neurodegenerative diseases (NDDs) pose a significant global health threat. In particular, Alzheimer disease, the most common type causing dementia, remains an incurable disease. Alzheimer disease is thought to be associated with an imbalance of reactive oxygen species (ROS) in neurons, and scientists considered ROS modulation as a promising strategy for novel remedies. In the study, human neural cell line SH-SY5Y was used in probing the effect of combining noninvasive high-frequency low-intensity pulsed electric field (H-LIPEF) and brain-derived neurotrophic factor (BDNF) in protection against hydrogen peroxide (H2O2)-induced neuron damage. Our result finds that the combination approach has intensified the neuroprotective effect significantly, perhaps due to H-LIPEF and BDNF synergistically increasing the expression level of the phosphorylated epidermal growth factor receptor (p-EGFR), which induces the survival-related mitogen-activated protein kinases (MAPK) proteins. The study confirmed the activation of extracellular signal-regulated kinase (ERK) and the downstream pro-survival and antioxidant proteins as the mechanism underlying neuron protection. These findings highlighted the potential of H-LIPEF combined with BDNF in the treatment of NDDs. Furthermore, BDNF-mimetic drugs combining with noninvasive H-LIPEF to patients is a promising approach worthy of further research. This points to strategies for selecting drugs to cooperate with electric fields in treating neurodegenerative disorders.

Oridonin protects hydrogen peroxide-induced human lens epithelial cell damage by regulating the NLRP3/NF-κB pathway and Nrf2-mediated oxidative stress

Cataract is the clouding of eye lens, and is the leading cause of visual impairment and blindness worldwide. There is an urgent need to develop new drugs to combat this disease. Oridonin (ORI), isolated from Rabdosia rubescens, is a natural substance that has been studied as an activator of nuclear factor erythroid 2-related factor 2 (Nrf2) and covalent inhibitor of NLR family pyrin domain containing 3 (NLRP3). Whether ORI has a therapeutic effect on human lens’ epithelial cell injury needs further study. In this study, we used cataract lens epithelial cell lines HLE-B3 and SRA01/04. We found using the MTT assay that ORI treatment increased cell viability induced by hydrogen peroxide (H2O2). In addition, ORI suppressed the apoptosis of H2O2-induced HLE-B3 and SRA01/04 cells detected by flow cytometry and Western blot analysis. Our data further revealed that ORI regulated nuclear factor, erythroid 2 (NFE2) like bZIP transcription factor 2 (Nrf2)-mediated oxidative stress by enzyme-linked-immunosorbent serologic assay. We further found that ORI inhibited NLRP3/nuclear factor-κb (NF-κB) pathway in H2O2-induced HLE-B3 and SRA01/04 cells by Western blot analysis. Therefore, these results suggested that ORI could have the potential to serve as a promising drug to treat cataract.

Guanxin V alleviates acute myocardial infarction by restraining oxidative stress damage, apoptosis, and fibrosis through the TGF-β1 signalling pathway

BackgroundOxidative stress, apoptosis, and fibrosis have important roles in acute myocardial infarction, which is the main cause of global morbidity and mortality. Guanxin V significantly ameliorates acute myocardial infarction, the underlying mechanism, however, is still unclear. PurposeIn this study, we detected the anti-oxidative, anti-apoptotic, and anti-fibrosis effects of Guanxin V on acute myocardial infarction. MethodsWe used left anterior descending coronary artery ligation to construct an acute myocardial infarction model. Cardiac function, heart weight, infarction size, and histopathology were measured. Cardiomyocytes were treated with hydrogen peroxide to build an in vitro model. Cell apoptosis, fibrosis, and reactive oxygen species-related markers were tested. We observed the mitochondrial ultrastructure through transmission electron microscopy. The levels of collagens and TGF-β1 signalling were measured. The lentiviral vector containing the full-length TGF-β1 sequence was administered to investigate the rescue role of Guanxin V. ResultsGuanxin V significantly decreased apoptosis and inhibited oxidative stress damage and fibrosis in acute myocardial infarction. Hydrogen peroxide could stimulate cardiomyocytes to produce reactive oxygen species and Guanxin V could significantly reverse hydrogen peroxide-induced cell damage, inhibit oxidative stress damage, apoptosis, and fibrosis, and enhance mitochondrial dynamic balance. Mechanistically, Guanxin V attenuated oxidative stress damage, apoptosis, and fibrosis induced by the TGF-β1 signalling pathway activation. ConclusionsGuanxin V effectively relieved apoptosis, oxidative stress damage, and fibrosis through down-regulating the TGF-β1 signalling pathway, which enhances the knowledge of the cellular and molecular mechanism of Guanxin V in treating acute myocardial infarction.

Melatonin’s Antioxidative Characteristic in Human Aging Retinal Pigment Epithelial Cells

In this study, the antioxidative effect of melatonin was investigated in aging retinal pigment epithelial cells in vitro. The objective of this study is to explore the administration of melatonin pharmacological doses for the prevention of aging symptoms.Specific concentrations of melatonin (20 µM, 40 µM and 80 µM) were used to treat hydrogen peroxide-induced aging retinal pigment epithelial cells and flow cytometry was employed to examine retinal pigment epithelial cell apoptosis. A specific probe was utilized to detect the intracellular reactive oxygen species concentration and apoptosis-associated proteins were detected in real-time polymerase chain reaction. Commercially available assay kits detected the expression of oxidative biomarkers, superoxide dismutase, malondialdehyde and glutathione.In comparison to normal cells, the aging retinal pigment epithelial cell model had lower cell viability, higher apoptosis rates and a more severe oxidation status. Melatonin increased cell viability while lowering apoptosis and oxidative stress. It influenced the expression of apoptosis-related proteins as well as oxidative stress indicators. Finally, treatment with melatonin was able to regulate proliferation, oxidative stress and apoptosis in aging retinal pigment epithelial cells.The application of melatonin may be a novel strategy to protect against age-related changes in age-related macular degeneration. Melatonin has protective effects against hydrogen peroxide-induced retinal cell death. It inhibits hydrogen peroxide-induced retinal pigment epithelial cell damage and decreases the apoptosis rate.

Chrysin and rutin protect against hydrogen peroxide and tert-butyl hydroperoxide induced oxidative cell damage

Objective: Chrysin and rutin are two dietary flavonoids lying in fruits or honey bee’s products. Their pharmacological properties include antioxidant, anti-inflammatory, anticancer, neuroprotection and immunomodulatory. In the current study, the potentiality of chrysin and rutin to protect human gingival fibroblasts against oxidative cell damage has been investigated in vitro. 
 Method: Human gingival fibroblasts, passage 3, were concomitantly put in contact with the cytotoxic compounds and chrysin or rutin for 24 h at 37 °C, 5% CO2 atmosphere, and 96% humidity. The amount of viable cell after the incubated time was recorded by using the thiazolyl blue tetrazolium bromide (MTT) assay. 
 Results: Chrysin in all tested concentration didn’t exhibit any cytoprotective effect against the tert-butyl hydroperoxide-induced oxidative cell damage. Moreover, chrysin in a low concentration (5 and 10 µg/mL) didn’t protect the fibroblasts against oxidative cell damage induced by the hydrogen peroxide. However, chrysin in a concentration of 20 µg/mL showed a significant cytoprotective activity in the hydrogen peroxide-induced cell damage (p < 0.05). Rutin in all tested concentrations protected fibroblasts against hydrogen peroxide and tert-butyl hydroperoxide-induced oxidative cell damage. The cytoprotective effect of rutin didn’t increase with the increase of the concentration when hydrogen peroxide is used to induce oxidative cell damage. However, rutin has protected cells against the tert-butyl hydroperoxide cytotoxicity in a concentration dependent manner.
 Conclusion: Given to the interesting cytoprotective activities exhibited by chrysin and rutin, further investigations to highlight their cytoprotective involved mechanisms are justified. 
 Keywords: Chrysin, Cytoprotective, Fibroblasts, Rutin.

Madecassic acid protects human periodontal ligament fibroblasts against hydrogen peroxide-induced cell damage by maintaining mitochondrial membrane potential

Madecassic acid protects human periodontal ligament fibroblasts against hydrogen peroxide-induced cell damage by maintaining mitochondrial membrane potential

Neuroprotective Effects of Methyl Caffeate against Hydrogen Peroxide-Induced Cell Damage: Involvement of Caspase 3 and Cathepsin D Inhibition.

Finding effective neuroprotective strategies to combat various neurodegenerative disorders still remain a clinically unmet need. Methyl caffeate (MC), a naturally occurring ester of caffeic acid, possesses antioxidant and anti-inflammatory activities; however, its role in neuroprotection is less investigated. In order to better characterize neuroprotective properties of MC, we tested its effectiveness in various models of neuronal cell injury in human neuroblastoma SH-SY5Y cells and in mouse primary neuronal cell cultures. MC at micromolar concentrations attenuated neuronal cell damage induced by hydrogen peroxide (H2O2) in undifferentiated and neuronal differentiated SH-SY5Y cells as well as in primary cortical neurons. This effect was associated with inhibition of both caspase-3 and cathepsin D but without involvement of the PI3-K/Akt pathway. MC was neuroprotective when given before and during but not after the induction of cell damage by H2O2. Moreover, MC was protective against 6-OHDA-evoked neurotoxicity in neuronal differentiated SH-SY5Y cells via inhibition of necrotic and apoptotic processes. On the other hand, MC was ineffective in models of excitotoxicity (induced by glutamate or oxygen–glucose deprivation) and even moderately augmented cytotoxic effects of the classical apoptotic inducer, staurosporine. Finally, in undifferentiated neuroblastoma cells MC at higher concentrations (above 50 microM) induced cell death and when combined with the chemotherapeutic agent, doxorubicin, it increased the cell damaging effects of the latter compound. Thus, neuroprotective properties of MC appear to be limited to certain models of neurotoxicity and depend on its concentrations and time of administration.

Quercetin, but not rutin, attenuated hydrogen peroxide-induced cell damage via heme oxygenase-1 induction in endothelial cells

Oxidative stress plays an important role in the pathogenesis of cardiovascular disease. Quercetin, a naturally occurring flavonoid presents in plants and human diet, has been reported to exert antioxidant properties in vivo and in vitro. The upregulation of antioxidant enzyme heme oxygenase-1 (HMOX1) in endothelial cells is considered to be beneficial in cardiovascular disease. In this work, we tested whether quercetin might suppress hydrogen peroxide (H2O2)-induced cell damage in endothelial cells by augmenting this cellular antioxidant defense. It was found that quercetin upregulated HMOX1 expression to protect endothelial cells against oxidative stress, and the protective effects of quercetin on H2O2-induced endothelial cell damage (such as loss of cell viability and reduction of nitric oxide) could be abolished by the specific small-interfering RNA against HMOX1 expression or HMOX1 activity inhibitor. In addition, the activation of ERK/Nrf2 signaling pathway was critical to the upregulation of HMOX1 induced by quercetin. Consistent with its non-effective ability to induce HMOX1, rutin (the glycoside of quercetin) showed less protective effects on H2O2-induced cell damage than quercetin. Therefore, quercetin could attenuate oxidative stress-induced endothelial cell damage at least partly through ERK/Nrf2/HMOX1 pathway. Our results also suggested a novel mechanism for the anti-oxidant property of quercetin and might explain in part the protective cardiovascular effects of diets rich in these compounds.

Lichen Based Synthesis of Zinc Oxide Nanoparticles and Evaluation of its Neurotoxic Effects on Human Neuroblastoma Cells

Nanoparticles, smaller than 100 nm are synthesized by chemical and physical methods. Biological synthesis of nanoparticles is very popular in science recently. The aim of the study is green synthesis of zinc oxide nanoparticles (ZnO NPs) using the lichen extract (Ramalina fraxinea) and investigating the cytotoxic effects of ZnO NPs on human neuroblastoma cells (SHSY-5Y). Despite the widespread use of ZnO NPs, a limited number of studies have investigated the neurobiological effects of ZnO NP. Therefore, we tested the neurotoxic effect of green synthesized ZnO NPs administration and its neuroprotective effect against hydrogen peroxide-induced cell damage on SH-SY5Y human neuroblastoma cell line. The absorbance peak of the ZnO NPs was detected by UV–visible spectroscopy (UV-Vis) at 330 nm. The average diameter of ZnO NPs was measured as about 21 nm by Scanning Electron Microscope (SEM) and Field Emission Scanning Electron Microscope (FE-SEM) images. According to X-ray Diffraction (XRD) diagram, ZnO NPs were hexagonal in structure. The peaks observed in the Fourier Transform Infrared (FT-IR) test showed functional groups in the structure of the nanoparticles. According to our results, ZnO NPs may have beneficial effects at the low concentrations while neurotoxic effects at the higher doses in SH-SY5Y. In addition, we indicate that hydrogen peroxide-induced cell death could not reverse by ZnO NPs and its higher doses potentiated the neurodegenerative effect of hydrogen peroxide. In conclusion, here we report that ZnO NPs, widely used in various products, may have beneficial or harmful effects in a dose-dependent manner and play a role in neuropsychiatric disease, especially neurodegenerative diseases. This is the first study dealing with neurotoxicity on SHSY-5Y of Ramalina fraxinea extract based ZnO NPs.

Towards application of water extract from heat-killed Lactococcus lactis H61 as a cosmetic ingredient.

We previously reported that oral administration of heat-killed Lactococcus lactis H61 improves certain human skin properties. For topical application of this strain, we reasoned that a bacterial cell extract obtained with an aqueous solvent could be readily formulated as a cosmetic ingredient. In the present study, we characterized the water extract from heat-killed H61. The extract had inhibitory activity for angiotensin-converting enzyme, which is known as suppression of inflammation of skin, and absorbed electromagnetic radiation in the UVB range. UVB-irradiated normal human epidermal keratinocytes (NHEKs) had lower viability than nonirradiated NHEKs. The NHEK survival rate was significantly higher in cells treated with the extract at 10mg dried cells per ml prior to UVB exposure than in untreated cells or cells treated with lower extract concentrations. At this concentration, the extract also inhibited the production of interleukin-8 induced by UVB. The extract did not protect against hydrogen peroxide-induced cell damage. These data indicate that topical application of the H61 extract alleviates UVB damage and reduces inflammation in skin cells. The present study expands the potential application of strain H61 to its use as a cosmetic ingredient in addition to its use in the food industry. SIGNIFICANCE AND IMPACT OF THE STUDY: In our previous report, oral administration of heat-killed Lactococcus lactis H61 improved certain human skin properties. This study aimed exploring the potential topical use of this strain. The water extract derived from heat-killed cells with angiotensin-converting enzyme inhibitory activity, which is known as suppression of inflammation of skin, could protect normal human epidermal keratinocytes (NHEKs) from damage caused by UVB. Higher interleukin-8 production by UVB-exposed NHEKs than nontreated cells was suppressed by addition of the extract. The extract absorbed electromagnetic radiation in the UVB range. This extract could help in the maintenance of skin health by suppressing inflammation.

(Z)-7,4'-Dimethoxy-6-hydroxy-aurone-4-O-β-glucopyranoside exerts neuroprotective effects in vitro and anxiolytic activity in vivo.

This study investigated the neuroprotective effects of (Z)-7,4'-dimethoxy-6-hydroxy-aurone-4-O-β-glucopyranoside (DHG) against hydrogen peroxide-induced cell damage in PC12 cells and further evaluated its effects on doxorubicin-induced anxiety-like behavior in rats. PC12 cells were treated with different concentrations of DHG (1-10 µM) for 24 h and then exposed to 0.2 mM hydrogen peroxide for 12 h. Cell viability was measured using the 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium-bromide and lactate dehydrogenase assay. The apoptosis was detected by annexin V-PI staining. Oxidative stress was confirmed in PC12 cells by enzyme-linked immunosorbent assay, real-time PCR, and western blot. The anxiolytic effects of DHG were evaluated in the elevated plus maze test. Our results showed that DHG treatment significantly increased cell viability and decreased PC12 cell apoptosis induced by hydrogen peroxide by increasing the mitochondrial membrane potential, decreasing the cytochrome c release, inhibiting the activities of caspase-3 and caspase-9, and regulating the expression of apoptosis-related proteins. Moreover, DHG treatment effectively attenuated the redox imbalance in PC12 cells by enhancing the activity of superoxide dismutase and increasing the level of glutathione, as well as decreasing levels of malondialdehyde and intracellular reactive oxygen species. Furthermore, DHG treatment significantly mitigated the doxorubicin-induced adverse behavioral changes in rats. These results indicate the neuroprotective and antiapoptotic properties of DHG exerted by counteracting the oxidative stress and highlight DHG as a potential therapeutic regimen for behavior impairment of anxiety.

IL-22 alleviates hydrogen peroxide-induced hepatocarcinoma cell damage through activating autophagy

Objective To investigate the role of interleukin-22 (IL-22)-regulated autophagy in hydrogen peroxide (H2O2)-induced hepatocarcinoma cell damage. Methods HepG2 cells were transfected with pEGFP-LC3 and then cultured in RPMI 1640 medium free of fetal bovine serum (FBS) or containing 1% or 10% FBS. These cells were pretreated with rapamycin or an autophagy inhibitor (3-MA) and then stimulated with recombinat human IL-22 (rhIL-22). GFP-LC3 puncta formation and autophagy signaling activation were measured. MTT assay was performed to detect cell viability. Results rhIL-22 significantly promoted GFP-LC3 puncta formation and LC3-Ⅱ expression in HepG2 cells treated with different stimulation protocols. The autophagy pathway inhibitor, 3-MA, dramatically suppressed the rhIL-22-activated autophagy signals. rhIL-22 attenuated H2O2-mediated HepG2 cell death and that could be inhibited by 3-MA. Conclusion IL-22 promoted the activation of autophagy signaling pathways and alleviated H2O2-mediated HepG2 cell damage. Key words: Interleukin-22; Autophagy; Hepatocarcinoma cell; Cell death; Hydrogen peroxide

Protection of bovine mammary epithelial cells from hydrogen peroxide-induced oxidative cell damage by selenium

The uncontrolled release of arachidonic acid (ARA) and its metabolism by lipoxygenase (LOX) pathway can induce and aggravate cellular oxidative stress. Selenium (Se) is an integral part of some antioxidative selenoproteins and may protect cells from oxidative damage by modulating ARA release and metabolism. The present study aimed to investigate the protective response of Se against hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>)-induced oxidative damage in bovine mammary epithelial cells (BMECs). The BMECs were incubated for 24 h in serum-free medium and then divided into four groups randomly. The cells in groups 1 and 2 were subsequently incubated for 30 h in serum-free medium containing 0 (control) and 50 nM Se (Se treatment group). The cells in groups 3 and 4 were incubated for 24 h in serum-free medium containing 0 and 50 nM Se, and then treated with 600 μM H<sub>2</sub>O<sub>2</sub> for 6 h (H<sub>2</sub>O<sub>2</sub> damage group and Se prevention group). The results showed that Se attenuated the H<sub>2</sub>O<sub>2</sub>-induced production of reactive oxygen species and the decrease of antioxidative enzymes as glutathione peroxidase (GPX), thioredoxin reductase (TrxR), selenoprotein P (SelP), superoxide dismutase, and catalase in BMECs. The preventive effects of Se on the decrease of selenoprotein activity were demonstrated further by the increase of mRNA expression for GPX1, TrxR1, and SelP, and protein expression for GPX1 and TrxR1. Pretreatment of cells with Se inhibited the H<sub>2</sub>O<sub>2</sub>-induced increase of mRNA expressions and activities for cytosolic phospholipase A2 and 5-lipoxygenase, ARA release, and 15-hydroperoxyeicosatetraenoic acid production. Se also blocked the H<sub>2</sub>O<sub>2</sub>-induced activation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase but not that of extracellular signal-regulated kinase. These results suggested that Se may protect BMECs against H<sub>2</sub>O<sub>2</sub>-induced oxidative damage by increasing selenoproteins synthesis, inhibiting MAPK pathway, and then decreasing ARA release and its metabolism by LOX pathway.

Glycyl-alanyl-histidine protects PC12 cells against hydrogen peroxide toxicity

BackgroundPeptides with cytoprotective functions, including antioxidants and anti-infectives, could be useful therapeutics. Carnosine, β-alanine-histidine, is a dipeptide with anti-oxidant properties. Tripeptides of Ala-His-Lys, Pro-His-His, or Tyr-His-Tyr are also of interest in this respect.ResultsWe synthesized several histidine-containing peptides including glycine or alanine, and tested their cytoprotective effects on hydrogen peroxide toxicity for PC12 cells. Of all these peptides (Gly-His-His, Ala-His-His, Ala-His-Ala, Ala-Ala-His, Ala-Gly-His, Gly-Ala-His (GAH), Ala-His-Gly, His-Ala-Gly, His-His-His, Gly-His-Ala, and Gly-Gly-His), GAH was found to have the strongest cytoprotective activity. GAH decreased lactate dehydrogenase (LDH) leakage, apoptosis, morphological changes, and nuclear membrane permeability changes against hydrogen peroxide toxicity in PC12 cells. The cytoprotective activity of GAH was superior to that of carnosine against hydrogen peroxide toxicity in PC12 cells. GAH also protected PC12 cells against damage caused by actinomycin D and staurosporine. Additionally, it was found that GAH also protected SH-SY5Y and Jurkat cells from damage caused by hydrogen peroxide, as assessed by LDH leakage.ConclusionThus, a novel tripeptide, GAH, has been identified as having broad cytoprotective effects against hydrogen peroxide-induced cell damage.

The ATM kinase inhibitor KU-55933 provides neuroprotection against hydrogen peroxide-induced cell damage via a γH2AX/p-p53/caspase-3-independent mechanism: Inhibition of calpain and cathepsin D

The role of the kinase ataxia-telangiectasia mutated (ATM), a well-known protein engaged in DNA damage repair, in the regulation of neuronal responses to oxidative stress remains unexplored. Thus, the neuroprotective efficacy of KU-55933, a potent inhibitor of ATM, against cell damage evoked by oxidative stress (hydrogen peroxide, H2O2) has been studied in human neuroblastoma SH-SY5Y cells and compared with the efficacy of this agent in models of doxorubicin (Dox)- and staurosporine (St)-evoked cell death. KU-55933 inhibited the cell death induced by H2O2 or Dox but not by St in undifferentiated (UN-) and retinoic acid-differentiated (RA)-SH-SY5Y cells, with a more pronounced effect in the latter cell phenotype. Furthermore, this ATM inhibitor attenuated the Dox- but not H2O2-induced caspase-3 activity in both UN- and RA-SH-SY5Y cells. Although KU-55933 inhibited the H2O2- and Dox-induced activation of ATM, it attenuated the toxin-induced phosphorylation of the proteins H2AX and p53 only in the latter model of cell damage. Moreover, the ATM inhibitor prevented the H2O2-evoked increases in calpain and cathepsin D activity and attenuated cell damage to a similar degree as inhibitors of calpain (MDL28170) and cathepsin D (pepstatin A). Finally, we confirmed the neuroprotective potential of KU-55933 against the H2O2- and Dox-evoked cell damage in primary mouse cerebellar granule cells and in the mouse hippocampal HT-22 cell line. Altogether, our results extend the neuroprotective portfolio of KU-55933 to a model of oxidative stress, with this effect not involving inhibition of the γH2AX/p-p53/caspase-3 pathway and instead associated with the attenuation of calpain and cathepsin D activity.

Antioxidant and Anti-aging Effects of Extracts from Rhododendron mucronulatum Turcz. in Human Dermal Fibroblast

Skin aging is associated with increased reactive oxygen species (ROS) production by human cells, which is characterized by wrinkles and atypical pigmentation. Use of antioxidants is an effective approach to prevent symptoms associated with ROS-induced skin aging. Although synthetic antioxidants have been used to remove free radicals, several studies have reported that the synthetic antioxidants have side effects that cause long-term edema, which subsequently results in cancer and intracellular toxicity. Therefore, the study of safe and functional antioxidants derived from natural products is necessary for replacement of synthetic antioxidants. In this study, the antioxidant and anti-aging effect of Rhododendron mucronulatum Turcz. extracts (RTE) on human dermal fibroblasts (HDFs) were investigated. We confirmed that RTE markedly reduced hydrogen peroxide-induced cell damage, intracellular ROS, and oxidative stress-induced senescence in HDFs. These results suggest that RTE is potential natural source of antioxidant and anti-aging compounds.

Protection of Bovine Mammary Epithelial Cells from Hydrogen Peroxide-Induced Oxidative Cell Damage by Resveratrol.

The mammary epithelial cells (MECs) of high-producing dairy cows are likely to be subject to oxidative stress (OS) due to the intensive cell metabolism. The objectives of this study were to investigate the cytoprotective effects of resveratrol against hydrogen peroxide- (H2O2-) induced OS in cultured bovine MECs (MAC-T). Pretreatment of MAC-T cells with resveratrol could rescue the decrease in cell viability and resulted in lower intracellular reactive oxygen species (ROS) accumulation after H2O2 exposure. Resveratrol helped MAC-T cells to prevent H2O2-induced endoplasmic reticulum stress and mitochondria-related cell apoptosis. Moreover, resveratrol induced mRNA expression of multiple antioxidant defense genes in MAC-T cells under normal/oxidative conditions. Nuclear factor erythroid 2-related factor 2 (Nrf2) was required for the cytoprotective effects on MAC-T cells by resveratrol, as knockdown of Nrf2 significantly abolished resveratrol-induced cytoprotective effects against OS. In addition, by using selective inhibitors, we further confirmed that the induction of Nrf2 by resveratrol was mediated through the prolonged activation of PI3K/Akt and ERK/MAPK pathways but negatively regulated by p38/MAPK pathway. Overall, resveratrol has beneficial effects on bovine MECs redox balance and may be potentially used as a therapeutic medicine against oxidative insult in lactating animals.

Antioxidant Activity of Ethanol and Water Extracts from Lentil (Lens Culinaris)

The purpose of this study was to evaluate the antioxidative activities of water and ethanolic extracts from lentil (Lens Culinaris). The antioxidant effects of lentil extracts were evaluated, including 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and ferric reducing antioxidant power (FRAP). We also evaluated the protection effect on hydrogen peroxide-induced oxidative damage in PC-12 cells via propidium iodide (PI) staining using a flow cytometer. Lentil extracts decreased cell death in PC-12 cells due to hydrogen peroxide-induced oxidative damage in a dose-dependent manner. The findings of this study suggested that lentil has the potential to protect against hydrogen peroxide-induced cell damage and should be considered as a prospective functional food.

An Involvement of PI3-K/Akt Activation and Inhibition of AIF Translocation in Neuroprotective Effects of Undecylenic Acid (UDA) Against Pro-Apoptotic Factors-Induced Cell Death in Human Neuroblastoma SH-SY5Y Cells.

Undecylenic acid (UDA), a naturally occurring 11-carbon unsaturated fatty acid, has been used for several years as an economical antifungal agent and a nutritional supplement. Recently, the potential usefulness of UDA as a neuroprotective drug has been suggested based on the ability of this agent to inhibit μ-calpain activity. In order to verify neuroprotective potential of UDA, we tested protective efficacy of this compound against cell damage evoked by pro-apoptotic factors (staurosporine and doxorubicin) and oxidative stress (hydrogen peroxide) in human neuroblastoma SH-SY5Y cells. We showed that UDA partially protected SH-SY5Y cells against the staurosporine- and doxorubicin-evoked cell death; however, this effect was not connected with its influence on caspase-3 activity. UDA decreased the St-induced changes in mitochondrial and cytosolic AIF level, whereas in Dox-model it affected only the cytosolic AIF content. Moreover, UDA (1-40 μM) decreased the hydrogen peroxide-induced cell damage which was connected with attenuation of hydrogen peroxide-mediated necrotic (PI staining, ADP/ATP ratio) and apoptotic (mitochondrial membrane potential, caspase-3 activation, AIF translocation) changes. Finally, we demonstrated that an inhibitor of PI3-K/Akt (LY294002) but not MAPK/ERK1/2 (U0126) pathway blocked the protection mediated by UDA in all tested models of SH-SY5Y cell injury. These in vitro data point to UDA as potentially effective neuroprotectant the utility of which should be further validated in animal studies.

Protective effects of ugonin K on hydrogen peroxide-induced osteoblast cell damage

Oxidative stress is a risk factor in the pathogenesis of osteoporosis. The present results showed that ugonin K, an osteogenic constituent presented in Helminthostachys zeylanica, was more potent than ascorbic acid, α-tocopherol and probucol, in protecting osteoblasts against hydrogen peroxide (H2O2)-induced oxidative injury in murine osteoblast MC3T3-E1 cells. Ugonin K suppressed H2O2-induced reactive oxygen species (ROS) production and the Annexin V/propidium iodide assay confirmed that decrease in cell viability by H2O2 was due to apoptosis. Suppression by Ugonin K of H2O2-induced activation of apoptotic signaling was evidenced by a decrease in expressions of cytosolic cytochrome c, active forms of caspase-9, caspase-3 and poly(ADP-ribose)polymerase (PARP). Treatment of cells with caspase inhibitor Ac-DEVD-cho recovered apoptosis and ugonin K decreased H2O2-triggered caspase 3 activity. Ugonin K-induced alleviation of cell viability was concentration-dependently attenuated by the estrogen receptor (ER) antagonist and the Src inhibitor, suggesting that activation of ER/Src signaling might also participate in the protective mechanisms. Furthermore, post-treatment with ugonin K after H2O2 challenge also rescued H2O2-induced osteoblast cell death. Our results showed that ugonin K protected osteoblasts from oxidative stress through regulation of ROS production and suppression of caspase cascade. These results suggest that ugonin K may be an alternative remedy for osteoporosis.