姜黄素对皮层神经元氧化损伤的保护作用

目的　观察姜黄素对第三丁基过氧化氢 (tert butylhy droperoxide,t BHP ,tBHP)诱导的大鼠皮层神经元氧化损伤的影响 ,探讨可能的机制。方法　培养胚胎鼠皮层神经元 ,MTT法测定细胞活力 ,DNA断裂评价细胞凋亡 ,流式细胞术测定线粒体膜电位和细胞内活性氧水平 ,分光光度法测定细胞内谷胱甘肽 (GSH)水平 ,Westernblot法测定Bcl 2和Bax蛋白和胞浆细胞色素C以及活化型半胱氨酸天冬氨酸蛋白酶 3(caspase 3)和多聚 (ADP 核糖 )聚合酶 [poly (ADP ribose)poly merase,PARP]水平。结果　姜黄素 (2 5～ 2 0 μmol·L-1)可有效减少tBHP对神经元的氧化损伤和tBHP引起的细胞内GSH水平降低 ,降低细胞内的活性氧水平 ,增加线粒体膜电位和细胞内GSH以及Bcl 2蛋白水平 ,减少线粒体内细胞色素C向胞浆释放和Bax蛋白表达水平 ,最终明显减少cas pase 3和PARP活化和tBHP引起的神经元凋亡。结论　姜黄素可减弱tBHP对原代皮层神经元的氧化损伤作用 ,其作用可能与降低细胞内的活性氧水平 ,保护线粒体功能有关     

姜黄素抗肿瘤作用机制的研究进展

多种恶性肿瘤细胞中表达细胞凋亡抑制蛋白（IAPs）,如：Survivin、NAIP、XIAP、Livin等,同样表达抗细胞凋亡Bcl-2家族蛋白。IAPS介导的凋亡抑制可能是肿瘤细胞耐药而存活的原因之一;Bcl-2家族蛋白在抗肿瘤凋亡及促其凋亡中发挥作用。姜黄素具有抗炎、抗氧化、抑制血管新生等,可以通过调控蛋白表达及相关信号通路促进细胞凋亡、抗肿瘤作用。     

Curcumin attenuates quinocetone-induced oxidative stress and genotoxicity in human hepatocyte L02 cells

Abstract

Quinocetone (QCT), a new quinoxaline 1,4-dioxides, has been used as antimicrobial feed additive in China. Potential genotoxicity of QCT was concerned as a public health problem. This study aimed to investigate the protective effect of curcumin on QCT-induced oxidative stress and genotoxicity in human hepatocyte L02 cells. Cell viability and intracellular reactive oxygen species (ROS), biomarkers of oxidative stress including superoxide dismutase (SOD) activity and glutathione (GSH) level were measured. Meanwhile, comet assay and micronucleus assay were carried out to evaluate genotoxicity. The results showed that, compared to the control group, QCT at the concentration ranges of 2–16?μg/mL significantly decreased L02 cell viability, which was significantly attenuated with curcumin pretreatment (2.5 and 5?μM). In addition, QCT significantly increased cell oxidative stress, characterized by increases of intracellular ROS level, while decreased endogenous antioxidant biomarkers GSH level and SOD activity (all p?<?0.05 or 0.01). Curcumin pretreatment significantly attenuated ROS formation, inhibited the decreases of SOD activity and GSH level. Furthermore, curcumin significantly reduced QCT-induced DNA fragments and micronuclei formation. These data suggest that curcumin could attenuate QCT-induced cytotoxicity and genotoxicity in L02 cells, which may be attributed to ROS scavenging and anti-oxidative ability of curcumin. Importantly, consumption of curcumin may be a plausible way to prevent quinoxaline 1,4-dioxides-mediated oxidative stress and genotoxicity in human or animals.     

Curcumin decreases oxidative stress in mitochondria isolated from liver and kidneys of high-fat diet-induced obese mice

Oxidative stress plays a key role in obesity and diabetes-related mitochondrial dysfunction. Mitochondrial dysfunction is characterized by increased oxidative damage, nitric oxide (NO) synthesis, and a reduced ratio of adenosine-5'-triphosphate (ATP) production/oxygen consumption. Curcumin represents a potential antioxidant and anti-inflammatory agent. In this study, our objective was to determine the effect of curcumin treatment on oxidative stress and mitochondrial dysfunction in high-fat diet (HFD)-induced obese mice (OM). These results suggest that curcumin treatment increased oxygen consumption and significantly decreased lipid and protein oxidation levels in liver mitochondria isolated from HFD-induced OM compared with those in the untreated OM (UOM). In kidney mitochondria, curcumin treatment significantly increased oxygen consumption and decreased lipid and protein peroxidation levels in HFD-induced OM when compared with those in UOM. Curcumin treatment neither has any effect on body weight gain nor have any effects on mitochondrial NO synthesis. These findings suggest that obesity induces oxidative stress and mitochondrial dysfunction, whereas curcumin may have a protective role against obesity-induced oxidative stress and mitochondrial dysfunction.     

木犀草素对大鼠皮层神经元氧化损伤的保护作用

目的研究木犀草素对于皮层神经元氧化损伤的保护作用及其机制。方法用200μmol·L-1H2O2处理皮层神经元造成神经元的氧化损伤,用LDH活性检测细胞死亡,MTT测定线粒体活性,荧光分光检测神经元线粒体膜电位,细胞内ROS的积累以及过氧化氢酶和谷胱甘肽的含量变化。结果20μmol·L-1的木犀草素能有效的保护H2O2导致的神经元死亡,有效维护线粒体膜电位和线粒体活性,减少细胞内ROS的累积,并能通过提高细胞内谷胱甘肽的含量有效对抗氧化损伤,同时对于H2O2造成的过氧化氢酶活力和谷胱甘肽含量的急剧下降也有很好的保护作用。结论木犀草素是一种比较有效的对抗神经元氧化损伤的保护剂,它很可能通过维持线粒体的活性而达到神经保护作用,并通过提高细胞内谷胱甘肽的水平,增强神经元抗氧化损伤的能力。     

Edaravone attenuates brain damage in rats after acute CO poisoning through inhibiting apoptosis and oxidative stress

Acute carbon monoxide (CO) poisoning is the most common cause of death from poisoning all over the world and may result in neuropathologic and neurophysiologic changes. Acute brain damage and delayed encephalopathy are the most serious complication, yet their pathogenesis is poorly understood. The present study aimed to evaluate the neuroprotective effects of Edaravone against apoptosis and oxidative stress after acute CO poisoning. The rat model of CO poisoning was established in a hyperbaric oxygen chamber by exposed to CO. Ultrastructure changes were observed by transmission electron microscopy (TEM). TUNEL stain was used to assess apoptosis. Immunohistochemistry and immunofluorescence double stain were used to evaluate the expression levels of heme oxygenase‐1 (HO‐1) and nuclear factor erythroid 2‐related factor 2 (Nrf‐2) protein and their relationship. By dynamically monitored the carboxyhemoglobin (HbCO) level in blood, we successfully established rat model of severe CO poisoning. Ultrastructure changes, including chromatin condensation, cytoplasm dissolution, vacuoles formation, nucleus membrane and cell organelles decomposition, could be observed after CO poisoning. Edaravone could improve the ultrastructure damage. CO poisoning could induce apoptosis. Apoptotic cells were widely distributed in cortex, striatum and hippocampus. Edaravone treatment attenuated neuronal apoptosis as compared with the poisoning group (P < 0.01). Basal expressions of HO‐1 and Nrf‐2 proteins were found in normal brain tissue. CO poisoning could activate HO‐1/Nrf‐2 pathway, start oxidative stress response. After the administration of Edaravone, the expression of HO‐1 and Nrf‐2 significantly increased (P < 0.01). These findings suggest that Edaravone may inhibit apoptosis, activate the Keapl‐Nrf/ARE pathway, and thus improve the ultrastructure damage and neurophysiologic changes following acute CO poisoning. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 372–379, 2016.     

Rotenone induces nephrotoxicity in rats: oxidative damage and apoptosis

Previous studies have examined rotenone toxicity on the human central nervous system, especially in the pathogenesis of Parkinson’s disease, but few have investigated the effects of rotenone on the kidney. Here, rotenone-induced nephrotoxicity was evaluated by determining morphological, biochemical, oxidative stress-related, and apoptotic factor alterations in rat renal tissue. Morphological and biochemical analyzes showed that rotenone administration to rats damaged renal tissue. Western blot results revealed that rotenone-induced oxidative damage, causing overproduction of glutathione, malonaldehyde, and reactive oxygen species (ROS), and inhibiting superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity. Rotenone also decreased the mitochondrial membrane potential and increased voltage-dependent anion channel (VDAC), caspase-3, and caspase-9 protein levels, indicating an association of apoptosis with renal damage. Our results suggest that glutathione, malonaldehyde, and ROS may be signals of rotenone-induced oxidative damage, and that the mitochondrial pathway plays a key role in apoptosis of renal cells following rotenone administration.     

Curcumin attenuates indomethacin-induced oxidative stress and mitochondrial dysfunction

Oxidative stress and mitochondrial dysfunction have been implicated in the pathogenesis of indomethacin-induced enteropathy. We evaluated the potential of curcumin, a known cytoprotectant, as an agent to protect against such effects. Rats were pretreated with curcumin (40 mg/kg by intra-peritoneal injection) before administration of indomethacin (20 mg/kg by gavage). One hour later, the small intestine was isolated and used for assessment of parameters of oxidative stress. Mitochondria, brush border membranes (BBM) and surfactant-like particles (SLP) were also isolated from the tissue. Mitochondria were used for assessment of functional integrity, estimation of products of lipid peroxidation and lipid content. BBM were used for estimation of products of lipid peroxidation and lipid content, while the SLP were used for measurement of lipid content. The results showed that oxidative stress and mitochondrial dysfunction occurred in the small intestine of indomethacin-treated rats. Pre-treatment with curcumin was found to ameliorate these drug-induced changes. Significant changes were seen in some of the lipids in the mitochondria, BBM and SLP in response to indomethacin. However, curcumin did not have any significant effect on these drug-induced changes. We conclude that curcumin, by attenuating oxidative stress and mitochondrial dysfunction, holds promise as an agent that can potentially reduce NSAID-induced adverse effects in the small intestine.     

线粒体介导的细胞凋亡的研究进展

细胞凋亡是由相关基因调控的程序化细胞死亡过程,线粒体在细胞凋亡中起重要的调控作用。该文对Cyt-c、活性氧、Bcl-2及AIF介导的细胞凋亡机制进行综述。     

TiO2 nanoparticles induce oxidative DNA damage and apoptosis in human liver cells

Abstract

Titanium dioxide nanoparticles (TiO₂ NPs), widely used in consumer products, paints, pharmaceutical preparations and so on, have been shown to induce cytotoxicity, genotoxicity and carcinogenic responses in vitro and in vivo. The present study revealed that TiO₂ NPs induce significant (p < 0.05) oxidative DNA damage by the Fpg-Comet assay even at 1 µg/ml concentration. A corresponding increase in the micronucleus frequency was also observed. This could be attributed to the reduced glutathione levels with concomitant increase in lipid peroxidation and reactive oxygen species generation. Furthermore, immunoblot analysis revealed an increased expression of p53, BAX, Cyto-c, Apaf-1, caspase-9 and caspase-3 and decreased the level of Bcl-2 thereby indicating that apoptosis induced by TiO₂ NPs occurs via the caspase-dependent pathway. This study systematically shows that TiO₂ NPs induce DNA damage and cause apoptosis in HepG2 cells even at very low concentrations. Hence the use of such nanoparticles should be carefully monitored.     

Attenuation of brain mitochondria oxidative damage by Albizia julibrissin Durazz: neuroprotective and antiemetic effects

Medicinal plants, as new drugs, are considered for treatment of insomnia, anxiety, depression, confusion, nausea, and vomiting symptoms. The current study aimed to evaluate the neuroprotective and antiemetic effects of Albizia. julibrissin Durazz. flower extract in the chickens. Emesis was induced by copper sulfate and ipecac (60 and 600?mg/kg, orally, respectively) and the methanolic extract (50, 100, and 200?mg/kg) were injected intraperitoneally (i.p.). Mitochondrial function, lipid peroxidation (LPO), protein carbonyl (PC) content, and catalase activity as biomarkers of oxidative damage were evaluated in the brain mitochondria. All doses of extract showed significant (p?<?0.001) antiemetic activity against induced emesis by copper sulfate and ipecac. Brain mitochondria function (by 50, 100, and 200?mg/kg of extract) were increased 48%, 85%, and 90% against emesis induced by ipecac and 32%, 18%, and 24% against emesis induced by copper sulfate, respectively. LPO and PC contents were significantly decreased after the administration of extract in emesis induced by copper sulfate and ipecac. A significant decrease (p?<?0.01) of CAT activity was observed in the extract (200?mg/kg) group in emesis induced by copper sulfate in chickens brain mitochondria. The present study suggests that the extract had antiemetic effects against emesis induced by copper sulfate and ipecac in young chickens via peripheral and central mechanisms. Neuroprotective effect of the extract could be due to the increase in bioactive compounds, plasma antioxidants, or direct free radical scavenging that could prevent lipid and protein alteration and impede the formation of oxidative damage.     

Prevention of cell damage in ischaemia: novel molecular targets in mitochondria

Ischaemia results in a decrease of blood supply to an organ. It may be sudden or progressive, partial or complete. In any case, the lack of oxygen induces a decrease in ATP generation followed by a reduction of cellular energy-dependent processes. When ischaemia is followed by a reperfusion, the efflux of oxygen in an anoxied organ promotes an excess of reactive oxygen species (ROS) generation, which impairs the restoration of ATP synthesis. Both effects induce cellular alterations that can lead to cell death in both necrotic and apoptotic forms. As ATP synthesis and ROS generation both occur in mitochondria, they are obvious targets for pharmacological interventions aiming to prevent or block deleterious effects induced by a lack of oxygen. Different approaches may be used according to the state of the pathological process under investigation. In general, prevention of the ischaemic process is more successful than the cure of the following reperfusion state. This review summarises pharmacological strategies designed to improve cellular protection before or during ischaemia–reperfusion acting via the mitochondria and highlights promising new mitochondrial targets to be considered for future therapies.     

细胞色素C、线粒体与凋亡

线粒体细胞色素C释放在细胞凋亡过程中起重要作用。细胞色素C释放到胞质后可引发caspase活化级联 ,导致细胞死亡。细胞色素C的释放是线粒体外膜通透性增高的结果。Bcl 2蛋白家族具有调控细胞色素C释放的功能。除细胞色素C外 ,线粒体膜间隙的凋亡诱导因子 (AIF)在凋亡过程中也释放至胞质 ,这两种途径充分保证了细胞死亡程序的有效执行。轻中度暂时性脑缺血后细胞色素C释放至胞质 ,早于DNA片段化     

Acrylonitrile induced apoptosis via oxidative stress in neuroblastoma SH-SY5Y cell

Acrylonitrile (ACN) is a chemical that is widely used in the production of plastics, acrylic fibers, synthetic rubbers and resins. It has been reported that ACN can cause oxidative stress, a condition which is well recognized as an apoptotic initiator; however, information regarding ACN-induced apoptosis is limited. This present study investigated whether ACN induces apoptosis in human neuroblastoma SH-SY5Y cells, and whether its apoptotic induction involves oxidative stress. The results showed that ACN caused activation of caspase-3, a key enzyme involved in apoptosis, in a dose- and time-dependent manner. Detection of sub-G1 apoptotic cell death and apoptotic nuclear condensation revealed that ACN caused an increase in the number of apoptotic cells indicating ACN induces apoptosis in SH-SY5Y cells. ACN dose- and time-dependently increased the level of proapoptotic protein, Bax. Pretreatment with N-acetylcysteine (NAC), an antioxidant, attenuated caspase-3 activation by ACN, as evidenced by a reduction in proteolysis of PARP, a known caspase-3 substrate, as well as in the number of sub-G1 apoptotic cells. Moreover, induction of Bax by ACN was abolished by NAC. Taken together, the results indicate that ACN induces apoptosis in SH-SY5Y cells via a mechanism involving generation of oxidative stress-mediated Bax induction.     

Roles of oxidative damage and mitochondria-mediated apoptosis in ethylbenzene-induced hepatotoxic effects in rat

Abstract

The mechanisms underlying hepatoxic effects of ethylbenzene still remain unknown. We investigated the toxic effects of ethylbenzene on liver and explored the mechanism of mitochondria-mediated apoptosis pathway. Forty male Sprague-Dawley rats were used as an in vivo model with ethylbenzene inhalation of 0, 433.5?mg/m³, 4335?mg/m³ and 6500?mg/m³ for 13 weeks. Levels of malondialdehyde, glutathione, glutathione peroxidase and superoxide dismutase were assayed. Meanwhile, the ultrastructure of hepatic tissues was observed and cell apoptosis was detected via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Furthermore, we investigated the expression levels of mRNA and protein of bax, bcl-2, cytochrome c, caspase-9 and caspase-3 in rat liver tissues. Compared with control group, the malondialdehyde levels were significantly elevated while glutathione levels and activities of glutathione peroxidase and superoxide dismutase were decreased, respectively. The mitochondria of liver appeared swollen with vacuolar structure and loss of cristae in 6500?mg/m³ ethylbenzene-treated group, and ethylbenzene induced a significant increase in the percentage of apoptotic cells as compared to the control group. In addition, enhanced mRNA and protein expression levels of all measured genes were observed in ethylbenzene-treated groups except the decreased bcl-2 expression levels. Our results indicated that ethylbenzene may induce oxidative damage and apoptosis in rat liver. Mitochondrial-mediated pathway was involved in the apoptosis process.     

l-carnitine protects rat hepatocytes from oxidative stress induced by T-2 toxin

Context: Oxidative stress and mitochondrial dysfunction are thought to be the main mechanism of T-2 toxin toxicity. T-2 toxin is the most potent trichothecene mycotoxin which is present in agricultural products. L-carnitine, besides its anti-oxidative properties, facilitates the transportation of long-chain fatty acids in to mitochondrial matrix. Objective: In this study we tested whether L-carnitine, an antioxidant and a facilitator for long-chain fatty acid transportation across mitochondrial membranes, could protect rat hepatocytes against toxicity induced by T-2 toxin. Materials and methods: L-carnitine in low and high doses (50 and 500?mg/kg) was administered for five consecutive days to male Wistar rats. Hepatocytes were isolated and freshly exposed to appropriate concentration of T-2 toxin for 2?h followed by oxidative stress and cell death evaluations. Results: Glutathione depletion, ROS overproduction and mitochondrial membrane potential collapse were determined under T-2 toxin exposure. Pretreatment with L-carnitine particularly at high-dose reduced toxicity and prevented the hepatocytes from abnormal caspase-3 activity and apoptosis. Conclusion: Low toxicity of L-carnitine and its mitochondrial protective effects promises an effective way to reduce or prevent the toxicity induced by certain environmental pollutants, including T-2 toxin.     

Geraniol attenuates 2-acetylaminofluorene induced oxidative stress,inflammation and apoptosis in the liver of wistar rats

Abstract

2-Acetylaminofluorene (2-AAF), is a well-known liver toxicant, generally used to induce tumors in laboratory animals. Geraniol (GE), a monoterpene found in essential oils of herbs and fruits, has been known to possess preventive efficacy against chemically induced toxicities. The present study was designed to analyze the protective effect of GE against 2-AAF induced oxidative stress, inflammation, hyperproliferation and apoptotic tissue damage in the liver of female Wistar rats. 2-AAF (0.02% w/w in diet) was administered and subjected to partial hepatectomy, as a mitogenic stimulus for the induction of hyperproliferation of liver tissue. GE was pre-treated orally at two different doses (100 and 200?mg/kg b.wt.) dissolved in corn oil. GE pre-treatment significantly ameliorated 2-AAF induced oxidative damage by diminishing tissue lipid peroxidation accompanied by the increase in enzymatic activities of catalase, glutathione peroxidase, glutathione reductase, superoxide dismutase and reduced glutathione content. The level of serum toxicity markers (AST, ALT, LDH) was found to be decreased. Pre-treatment with GE downregulated the expression of caspase-3,9, COX-2, NFkB, PCNA, iNOS, VEGF and significantly decreased disintegration of DNA. Histological findings further revealed that GE significantly restores the architecture of liver tissue. In the light of the above observations it may be concluded that GE may be used as preventive agent against 2-AAF induced oxidative stress, inflammation, hyperproliferation and apoptotic damage.     

Dual effects of hydrogen sulphide on focal cerebral ischaemic injury via modulation of oxidative stress-induced apoptosis

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Curcumin protects against cytotoxic and inflammatory effects of quartz particles but causes oxidative DNA damage in a rat lung epithelial cell line

Chronic inhalation of high concentrations of respirable quartz particles has been implicated in various lung diseases including lung fibrosis and cancer. Generation of reactive oxygen species (ROS) and oxidative stress is considered a major mechanism of quartz toxicity. Curcumin, a yellow pigment from Curcuma longa, has been considered as nutraceutical because of its strong anti-inflammatory, antitumour and antioxidant properties. The aim of our present study was to investigate whether curcumin can protect lung epithelial cells from the cytotoxic, genotoxic and inflammatory effects associated with quartz (DQ12) exposure. Electron paramagnetic resonance (EPR) measurements using the spin-trap DMPO demonstrated that curcumin reduces hydrogen peroxide-dependent hydroxyl-radical formation by quartz. Curcumin was also found to reduce quartz-induced cytotoxicity and cyclooxygenase 2 (COX-2) mRNA expression in RLE-6TN rat lung epithelial cells (RLE). Curcumin also inhibited the release of macrophage inflammatory protein-2 (MIP-2) from RLE cells as observed upon treatment with interleukin-1 beta (IL-1beta) and tumour necrosis factor-alpha (TNFalpha). However, curcumin failed to protect the RLE cells from oxidative DNA damage induced by quartz, as shown by formamidopyrimidine glycosylase (FPG)-modified comet assay and by immunocytochemistry for 8-hydroxydeoxyguanosine. In contrast, curcumin was found to be a strong inducer of oxidative DNA damage itself at non-cytotoxic and anti-inflammatory concentrations. In line with this, curcumin also enhanced the mRNA expression of the oxidative stress response gene heme oxygenase-1 (ho-1). Curcumin also caused oxidative DNA damage in NR8383 rat alveolar macrophages and A549 human lung epithelial cells. Taken together, these observations indicate that one should be cautious in considering the potential use of curcumin in the prevention or treatment of lung diseases associated with quartz exposure.