NNK诱发BEP2D细胞产生活性氧及其对DNA的损伤

通过测定细胞内和细胞上清中活性氧（ｒｅａｃｔｉｖｅ ｏｘｙｇｅｎ ｓｐｅｃｉｅｓ,ＲＯＳ）水平,以及ＤＮＡ 加合物——８－羟基脱氧鸟嘌呤核苷（８－ｈｙｄｒｏｘｙｄｅｏｘｙｇｕａｎｏｓｉｎｅ,ＯＨ８ｄＧ）含量,对烟草特异亚硝胺类化合物４－甲基亚硝胺－１（３－吡啶基）－１－丁酮（４－（ｍ ｅｔｈｙｌｎｉｔｒｏｓａｍ ｉｎｏ）－１－（３－ｐｙｒｉｄｙｌ）－１－ｂｕｔａｎｏｎｅ,ＮＮＫ）诱发人乳头状病毒永生化的人支气管上皮细胞（ｈｕｍ ａｎ ｐａｐｉｌｌｏｍ ａｖｉｒｕｓ－ｉｍ ｍ ｏｒｔａｌｉｚｅｄ ｈｕｍ ａｎｂｒｏｎｃｈｉａｌｅｐｉｔｈｅｌｉａｌｃｅｌｌｌｉｎｅ,ＢＥＰ２Ｄ）产生的ＲＯＳ及其对ＤＮＡ 的氧化损伤进行研究,并观察纳米硒的保护作用．结果表明,ＢＥＰ２Ｄ 细胞经不同浓度的ＮＮＫ 作用后,细胞内和细胞上清中ＲＯＳ以及ＯＨ８ｄＧ含量均显著增加,并有较好的剂量效应关系．１ μｍ ｏｌ·Ｌ－ １纳米硒（ｎａｎｏｓｅｌｅｎｕｉｍ ,ＮＳ）能明显抑制ＮＮＫ 诱发ＢＥＰ２Ｄ细胞产生的ＲＯＳ及ＯＨ８ｄＧ 水平．揭示ＮＮＫ 能造成细胞的氧化损伤,而ＮＳ对ＮＮＫ 所致细胞的氧化损伤有保护作用．     

Origin of cadmium-induced reactive oxygen species production: mitochondrial electron transfer versus plasma membrane NADPH oxidase

* Cadmium (Cd(2+)) is an environmental pollutant that causes increased reactive oxygen species (ROS) production. To determine the site of ROS production, the effect of Cd(2+) on ROS production was studied in isolated soybean (Glycine max) plasma membranes, potato (Solanum tuberosum) tuber mitochondria and roots of intact seedlings of soybean or cucumber (Cucumis sativus). * The effects of Cd(2+) on the kinetics of superoxide (O2*-), hydrogen peroxide (H(2)O(2)) and hydroxyl radical ((*OH) generation were followed using absorption, fluorescence and spin-trapping electron paramagnetic resonance spectroscopy. * In isolated plasma membranes, Cd(2+) inhibited O2*- production. This inhibition was reversed by calcium (Ca(2+)) and magnesium (Mg(2+)). In isolated mitochondria, Cd(2+) increased and H(2)O(2) production. In intact roots, Cd(2+) stimulated H(2)O(2) production whereas it inhibited O2*- and (*)OH production in a Ca(2+)-reversible manner. * Cd(2+) can be used to distinguish between ROS originating from mitochondria and from the plasma membrane. This is achieved by measuring different ROS individually. The immediate (相似文献   

Microvascular oxygenation,oxidative stress,NO suppression and superoxide dismutase during postischemic reperfusion

Increased formation of reactive oxygen species (ROS) on reperfusion after ischemia underlies ischemia-reperfusion (I/R) damage. We measured, in real time, oxygen tension in both microvessels and tissue and oxidant stress during postischemic reperfusion in the hamster cheek pouch microcirculation. We measured Po2 by using phosphorescence quenching microscopy and ROS production in the systemic blood. We evaluated the effects of a nitric oxide synthase inhibitor (NG-monomethyl-L-arginine, L-NMMA) and SOD on the oxidative stress during reperfusion. Microvascular injury was assessed by measuring diameter change, the perfused capillary length (PCL), and leukocyte adhesion. During early reperfusion, arteriolar Po2 was significantly lower than baseline, whereas capillary Po2 varied between 7 and 0 mmHg. Arterial blood flow did not regain baseline values, whereas Po2 returned to baseline in arterioles and tissue after 30 min of reperfusion. During 5 and 15 min of reperfusion, ROS increased by 72 and 89% versus baseline, respectively, and declined to baseline after 30 min of reperfusion. Pretreatment with SOD maintained ROS at normal levels, increased arteriolar diameter, blood flow, and PCL, and decreased leukocyte adhesion (P < 0.05). L-NMMA decreased ROS only within 5 min of reperfusion, which increased significantly by 72% later during reperfusion. L-NMMA worsened leukocyte adhesion (P < 0.05). In conclusion, our results show that the early reperfusion is characterized by low Po2 linked to increased production of ROS. At early reperfusion both SOD and L-NMMA decreased ROS production, whereas only SOD reduced it during later reperfusion. We suggest that low-flow hypoxia profoundly affects vascular endothelial damage during reperfusion through changes in ROS and nitric oxide production.     

Quantitative relationship between inhibition of respiratory complexes and formation of reactive oxygen species in isolated nerve terminals

In this study reactive oxygen species (ROS) generated in the respiratory chain were measured and the quantitative relationship between inhibition of the respiratory chain complexes and ROS formation was investigated in isolated nerve terminals. We addressed to what extent complex I, III and IV,respectively, should be inhibited to cause ROS generation. For inhibition of complex I, III and IV, rotenone, antimycin and cyanide were used, respectively, and ROS formation was followed by measuring the activity of aconitase enzyme. ROS formation was not detected until complex III was inhibited by up to 71 +/- 4%, above that threshold inhibition, decrease in aconitase activity indicated an enhanced ROS generation. Similarly, threshold inhibition of complex IV caused an accelerated ROS production. By contrast, inactivation of complex I to a small extent (16 +/- 2%) resulted in a significant increase in ROS formation, and no clear threshold inhibition could be determined. However, the magnitude of ROS generated at complex I when it is completely inhibited is smaller than that observed when complex III or complex IV was fully inactivated. Our findings may add a novel aspect to the pathology of Parkinson's disease, showing that a moderate level of complex I inhibition characteristic in Parkinson's disease leads to significant ROS formation. The amount of ROS generated by complex I inhibition is sufficient to inhibit in situ the activity of endogenous aconitase.     

Induction of tubular peroxisomes by UV irradiation and reactive oxygen species in HepG2 cells.

Peroxisomes in the human hepatoblastoma cell line HepG2 exhibit a high degree of plasticity. Whereas in confluent cultures they appear as small (0.1-0.3 micrometer) spherical particles, they undergo dramatic changes, forming elongated tubules measuring up to 5 micrometer on separation of cells and cultivation at low density. We recently showed that several growth factors, including nerve growth factor (NGF), induce the formation of tubular peroxisomes and that this induction is sensitive to K 252b, a specific tyrosine kinase inhibitor, suggesting the involvement of this signal transduction pathway. Because tyrosine kinase is also involved in signal transduction via the reactive oxygen species (ROS), we have analyzed in this study the effects of UV irradiation, H(2)O(2), and oxygen on tubulation of peroxisomes. UVC irradiation induced a significant increase in formation of tubular peroxisomes (40-50% of cells) and this effect was dose-dependently inhibited by pretreatment with N-acetyl cysteine, confirming the involvement of ROS in the UV effect. Furthermore, H(2)O(2) also directly induced the tubulation of peroxisomes, although to a lesser extent. Finally, cultivation under hypoxic conditions (1.5% O(2)) drastically reduced the inducing effect of fetal calf serum on tubulation of peroxisomes, suggesting the involvement of oxygen-mediated signaling. Taken together, our observations indicate that ROS induce the tubulation of peroxisomes in HepG2 cells. Because peroxisomes harbor most of the enzymes for catabolism of ROS, the tubulation and expansion of the peroxisome compartment could have a cell rescue function against the destructive effects of ROS.     

Electrochemical measurement of the flux of hydrogen peroxide releasing from RAW 264.7 macrophage cells based on enzyme-attapulgite clay nanohybrids

Determination of cellular ROS (reactive oxygen species) could lead to a better understanding of the clinical consequences of the enhancement in ROS concentration, and assisting in studies of the biological effect of ROS in cells. This work developed an electrochemical approach for measuring the flux of H(2)O(2) (a major ROS in living organisms) releasing from RAW 264.7 macrophage cells. This approach is based on the electrocatalytic reduction of the releasing H(2)O(2) at the biosensor of HRP-attapulgite/GC, which was fabricated by depositing the horseradish peroxidase-attapulgite nanohybrids on the glassy carbon (GC) electrode. The biosensor exhibited a rapid response, a wide linear range, a high sensitivity, a low detection limit, as well as good stability and repeatability due to using the natural mineral (attapulgite) as the enzyme immobilization substrate. In addition, some common coexisting ROS and compounds in biological system such as hypochlorite (OCl(-)), nitric oxide (NO), peroxynitrite (ONOO(-)), and ascorbic acid (AA) etc., did not cause any interference due to the use of a low operating potential (-400mV, versus SCE). Moreover, the developed approach can also be used for studying the effects of the stimulator loading and a variety of stimuli on the generation of H(2)O(2) in cells and the release flux of H(2)O(2) from cells. Therefore, this work has demonstrated a simple and effective sensing platform for detection of cellular H(2)O(2) released from cells such as RAW 264.7 cells, which has potential utility to cellular biology and pathophysiology.     

Generation of reactive oxygen species (ROS) is a key factor for stimulation of macrophage proliferation by ceramide 1-phosphate

We previously demonstrated that ceramide 1-phosphate (C1P) is mitogenic for fibroblasts and macrophages. However, the mechanisms involved in this action were only partially described. Here, we demonstrate that C1P stimulates reactive oxygen species (ROS) formation in primary bone marrow-derived macrophages, and that ROS are required for the mitogenic effect of C1P. ROS production was dependent upon prior activation of NADPH oxidase by C1P, which was determined by measuring phosphorylation of the p40phox subunit and translocation of p47phox from the cytosol to the plasma membrane. In addition, C1P activated cytosolic calcium-dependent phospholipase A(2) and protein kinase C-α, and NADPH oxidase activation was blocked by selective inhibitors of these enzymes. These inhibitors, and inhibitors of ROS production, blocked the mitogenic effect of C1P. By using BHNB-C1P (a photolabile caged-C1P analog), we demonstrate that all of these C1P actions are caused by intracellular C1P. It can be concluded that the enzyme responsible for C1P-stimulated ROS generation in bone marrow-derived macrophages is NADPH oxidase, and that this enzyme is downstream of PKC-α and cPLA(2)-α in this pathway.     

Neutrophil-induced changes in the biomechanical properties of endothelial cells: roles of ICAM-1 and reactive oxygen species

This study evaluated the changes in the biomechanical properties of endothelial cells (ECs) induced by neutrophil adhesion and the roles of ICAM-1 and reactive oxygen species (ROS) in modulating these changes. Neutrophil adherence to 24-h TNF-alpha-activated pulmonary microvascular ECs induced an increase in the apparent stiffness of ECs within 2 min, measured with magnetic twisting cytometry. An anti-ICAM-1 Ab blocked the EC stiffening response without inhibiting neutrophil adherence. Moreover, cross-linking ICAM-1 mimicked the stiffening response induced by neutrophils. The neutrophil-induced increase in the apparent stiffness of ECs was inhibited with 1% DMSO (a hydroxyl radical scavenger), allopurinol (a xanthine oxidase inhibitor), or deferoxamine (an iron chelator), suggesting that ROS may be involved in mediating the EC stiffening response. The cellular sources of ROS were determined by measuring the oxidation of dichlorofluorescein. Neutrophil adherence to TNF-alpha-activated ECs induced ROS production only in ECs, and not in neutrophils. This ROS production in ECs was completely prevented by the anti-ICAM-1 Ab and partially inhibited by allopurinol. These results suggest that ICAM-1-mediated signaling events during neutrophil adherence may activate xanthine oxidase, which in turn mediates the ROS production in ECs that leads to stiffening. ROS generated in ECs on neutrophil adherence appear to mediate cytoskeletal remodeling, which may modulate subsequent inflammatory responses.     

α-Mangostin promotes apoptosis of human rheumatoid arthritis fibroblast-like synoviocytes by reactive oxygen species-dependent activation of ERK1/2 mitogen-activated protein kinase

α-Mangostin (α-M) is a commonly used traditional medicine with various biological and pharmacological activities. Our study aimed to explore the effects and mechanism of α-M in regulating apoptosis of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS). α-M of 10 to 100 μM was used to treat RA-FLS for 24 hours, followed by measuring cell viability and apoptosis. The involvement of reactive oxygen species (ROS) and mitogen-activated protein kinases was detected. Treatment of α-M promoted apoptosis and reduced viability of RA-FLS in a dose-dependent manner. The mitochondrial membrane potential in RA-FLS was remarkably reduced by α-M treatment, accompanied by the cytochrome c accumulation in the cytosol and increased activities of caspase-3 and caspase-9. Moreover, we found that α-M treatment promoted ROS production and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. The proapoptotic activity of α-M in RA-FLS was markedly reversed by the co-induction with the ERK1/2 inhibitor LY3214996 or ROS scavenger N-acetyl-l -cysteine. In conclusion, our studies found that α-M had remarkable proapoptotic activities in RA-FLS, which is regulated by the induction of ROS accumulation and ERK1/2 phosphorylation. α-M may thus have potential therapeutic effects for rheumatoid arthritis.     

Radiation-induced long-lived extracellular radicals do not contribute to measurement of intracellular reactive oxygen species using the dichlorofluorescein method

The dichlorofluorescein method has become a standard technique for measuring reactive oxygen species (ROS) formed in cells by ionizing radiation. A recent report (Korystov et al., Radiat. Res. 168, 226-232, 2007) has suggested that the method is subject to an artifact in that it erroneously reports hydrogen peroxides generated in the extracellular medium as ROS formed intracellularly by ionizing radiation. It was hypothesized that radiation-induced extracellular peroxides enter cells in the minutes after radiation exposure and subsequently oxidize the intracellular dichlorofluorescin probe and that dichlorofluorescein fluorescence is not due to ROS formed intracellularly by ionizing radiation. We tested this hypothesis by measuring the contribution of long-lived radicals formed in medium by ionizing radiation on intracellular dichlorofluorescein fluorescence. We found no evidence that this artifact contributes significantly to intracellular dichlorofluorescein fluorescence. These results and those of Korystov et al. are discussed in view of cellular dichlorofluorescin leakage and radiation chemistry. We conclude that the dichlorofluorescein method is effective for quantifying intracellular ROS induced by ionizing radiation.     

The relationship between exhaled carbon monoxide and human neutrophil function in the Japanese general population

We have evaluated the relationship between exhaled carbon monoxide (CO) level and neutrophil‐related functions such as reactive oxygen species (ROS) production capability, phagocytic activity and serum opsonic activity in the general population. Serum opsonic activity was determined by measuring the effects of serum on neutrophil ROS production capability using lucigenin‐ and luminol‐dependent chemiluminescence (LgCL, LmCL). LgCL is associated with the detection of O₂^?, whereas LmCL mainly detects H₂O₂ and HOCl, which are higher reactive oxygen radicals. In females, exhaled CO level was found to have positive associations with ROS production capability and LgCL. However, the opposite tendency was seen between exhaled CO level and LmCL in both genders. This result suggests that neutrophil ROS production in females may have contributed to oxidative stress, which led to the increases in intrinsic CO and exhaled CO consequently. Such changes then may have inhibited the process of changing reactive oxygen radicals into higher oxidizing potential levels. Copyright © 2010 John Wiley & Sons, Ltd.     

Exposure of yeast cells to anoxia induces transient oxidative stress. Implications for the induction of hypoxic genes

The mitochondrial respiratory chain is required for the induction of some yeast hypoxic nuclear genes. Because the respiratory chain produces reactive oxygen species (ROS), which can mediate intracellular signal cascades, we addressed the possibility that ROS are involved in hypoxic gene induction. Recent studies with mammalian cells have produced conflicting results concerning this question. These studies have relied almost exclusively on fluorescent dyes to measure ROS levels. Insofar as ROS are very reactive and inherently unstable, a more reliable method for measuring changes in their intracellular levels is to measure their damage (e.g. the accumulation of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) in DNA, and oxidative protein carbonylation) or to measure the expression of an oxidative stress-induced gene, e.g. SOD1. Here we used these approaches as well as a fluorescent dye, carboxy-H(2)-dichloro-dihydrofluorescein diacetate (carboxy-H(2)-DCFDA), to determine whether ROS levels change in yeast cells exposed to anoxia. These studies reveal that the level of mitochondrial and cytosolic protein carbonylation, the level of 8-OH-dG in mitochondrial and nuclear DNA, and the expression of SOD1 all increase transiently during a shift to anoxia. These studies also reveal that carboxy-H(2)-DCFDA is an unreliable reporter of ROS levels in yeast cells shifted to anoxia. By using two-dimensional electrophoresis and mass spectrometry (matrix-assisted laser desorption ionization time-of-flight), we have found that specific proteins become carbonylated during a shift to anoxia and that some of these proteins are the same proteins that become carbonylated during peroxidative stress. The mitochondrial respiratory chain is responsible for much of this carbonylation. Together, these findings indicate that yeast cells exposed to anoxia experience transient oxidative stress and raise the possibility that this initiates the induction of hypoxic genes.     

Emerging technologies for non-invasive quantification of physiological oxygen transport in plants

Oxygen plays a critical role in plant metabolism, stress response/signaling, and adaptation to environmental changes (Lambers and Colmer, Plant Soil 274:7–15, 2005; Pitzschke et al., Antioxid Redox Signal 8:1757–1764, 2006; Van Breusegem et al., Plant Sci 161:405–414, 2001). Reactive oxygen species (ROS), by-products of various metabolic pathways in which oxygen is a key molecule, are produced during adaptation responses to environmental stress. While much is known about plant adaptation to stress (e.g., detoxifying enzymes, antioxidant production), the link between ROS metabolism, O₂ transport, and stress response mechanisms is unknown. Thus, non-invasive technologies for measuring O₂ are critical for understanding the link between physiological O₂ transport and ROS signaling. New non-invasive technologies allow real-time measurement of O₂ at the single cell and even organelle levels. This review briefly summarizes currently available (i.e., mainstream) technologies for measuring O₂ and then introduces emerging technologies for measuring O₂. Advanced techniques that provide the ability to non-invasively (i.e., non-destructively) measure O₂ are highlighted. In the near future, these non-invasive sensors will facilitate novel experimentation that will allow plant physiologists to ask new hypothesis-driven research questions aimed at improving our understanding of physiological O₂ transport.     

Proanthocyanidins accelerate the germination of cucumber (<Emphasis Type="Italic">Cucumis sativus</Emphasis> L.) seeds

Proanthocyanidins (PAs) are the end products of the flavonoid biosynthetic pathway in many seeds, but their biological function is rarely unknown during seed germination. In the present study, we observed that PAs pretreatment accelerated cucumber seeds germination with maximum efficiency at 0.15% by measuring germination percentage and radical length. Using inhibitors of abscisic acid (ABA), gibberellins (GA) and alternative oxidase (AOX) and H₂O₂ scavenger pretreatment and gene expression analysis, we found that the accelerated effect of 0.15% PAs on seed germination was due to the decreased ABA biogenesis and enhanced GA production. ROS are induced by PAs pretreatment. Then, the enhanced ROS contributed to GA and ethylene accumulation and ABA decrease in seeds. Moreover, the improvement of GA was involved in the further induction of antioxidant enzymes activities. Therefore, our findings uncover a novel role of PAs in seed germination and clarify the relationships between ROS, ABA, GA and ethylene during seed germination.     

Roles of sedentary aging and lifelong physical activity in exchange of glutathione across exercising human skeletal muscle

Reactive oxygen species (ROS) are important signaling molecules with regulatory functions, and in young and adult organisms, the formation of ROS is increased during skeletal muscle contractions. However, ROS can be deleterious to cells when not sufficiently counterbalanced by the antioxidant system. Aging is associated with accumulation of oxidative damage to lipids, DNA, and proteins. Given the pro-oxidant effect of skeletal muscle contractions, this effect of age could be a result of excessive ROS formation. We evaluated the effect of acute exercise on changes in blood redox state across the leg of young (23±1 years) and older (66±2 years) sedentary humans by measuring the whole blood concentration of the reduced (GSH) and oxidized (GSSG) forms of the antioxidant glutathione. To assess the role of physical activity, lifelong physically active older subjects (62±2 years) were included. Exercise increased the venous concentration of GSSG in an intensity-dependent manner in young sedentary subjects, suggesting an exercise-induced increase in ROS formation. In contrast, venous GSSG levels remained unaltered during exercise in the older sedentary and active groups despite a higher skeletal muscle expression of the superoxide-generating enzyme NADPH oxidase. Arterial concentration of GSH and expression of antioxidant enzymes in skeletal muscle of older active subjects were increased. The potential impairment in exercise-induced ROS formation may be an important mechanism underlying skeletal muscle and vascular dysfunction with sedentary aging. Lifelong physical activity upregulates antioxidant systems, which may be one of the mechanisms underlying the lack of exercise-induced increase in GSSG.     

Effect of Salmonella typhimurium enterotoxin (S-LT) on lipid peroxidation and cell viability levels of isolated rat enterocytes

Reactive oxygen species (ROS) are potent mediators of inflammatory disorders and may be of pathophysiological importance in S. typhimurium induced tissue damage. This study was carried out to investigate if ROS play a role in mediating the enterocyte damage during in vitro exposure to Salmonella typhimurium enterotoxin (S-LT). The ROS generation was detected by measuring the changes in the enterocyte arachidonic acid (AA) metabolism (measured indirectly by estimating the level of enterocyte damage in the absence and presence of the cyclooxygenase inhibitor, indomethacin) and xanthine oxidase activity. The enterocyte damage was estimated by measuring the changes in the level of lipid peroxidation and cell viability. The results obtained showed that the exposure of isolated rat enterocytes to S-LT resulted in an increased XO activity; an increased arachidonic acid metabolism, dose and time dependent increase in the level of lipid peroxidation and decreased cell viability. Lipid peroxidation decreased and cell viability increased in the presence of the antioxidant enzymes superoxide dismutase (SOD) or catalase. Thus the in vitro exposure of the enterocytes to S-LT is accompanied by an increased generation of ROS which may induce the lipid peroxidation of the enterocyte membrane thereby leading to a loss of cell viability.     

Flow cytometric analysis of the oxidative status of normal and thalassemic red blood cells.

BACKGROUND: The oxidative status of cells has been shown to modulate various cell functions and be involved in physiological and pathological conditions, including hereditary chronic anemias, such as thalassemia. It is maintained by the balance between oxidants, such as reactive oxygen species (ROS), and antioxidants, such as reduced glutathione (GSH). METHODS: We studied peripheral RBC derived from normal and thalassemic donors. Flow cytometric methods were used to measure (1) generation of ROS; (2) the content of reduced GSH; and (3) peroxidation of membrane lipids as an indication of membrane damage. RESULTS: ROS and lipid peroxidation were found to be higher, and GSH lower, in thalassemic RBC compared with normal RBC, both at baseline as well as following oxidative stress, such as exposure to hydrogen peroxide. To simulate a state of iron overload, normal RBC were exposed to extracellular ferric ammonium citrate or hemin, or their Hb was denatured by phenylhydrazine. All these treatments increased ROS and lipid peroxidation and decreased GSH. These effects were reversed by N-acetyl cysteine, a known ROS scavenger. CONCLUSIONS: Flow cytometry can be useful for measuring oxidative stress and its effects on RBC in various diseases and for studying various chemical agents as antioxidants.     

Antioxidant activity of the halophyte Limonium tetragonum and its major active components

In this study, the antioxidant potentials of crude extracts and solvent-partitioned fractions of Limonium tetragonum were assessed by measuring their ability to scavenge intracellular reactive oxygen species (ROS) generated in HT-1080 cells. Following activity-oriented separation, four flavonol glycosides were isolated as active principles and their chemical structures were determined by 2 D NMR and by comparison with reported spectral data. The isolated compounds (1?C4) were evaluated for their antioxidant capacity using three different activity tests; degree of occurrence of intracellular ROS, lipid peroxidation in HT-1080 cells and the extent of oxidative damage of genomic DNA purified from HT-1080 cells. All compounds exhibited significantly inhibited the generation of intracellular ROS and lipid peroxidation in HT-1080 cells, and significantly inhibited DNA oxidation. In addition, direct free radical scavenging effects of these compounds were investigated using the electron spin resonance (ESR) spin-trap technique.     

Peroxiredoxin 3 has a crucial role in the contractile function of skeletal muscle by regulating mitochondrial homeostasis

Antioxidant systems against reactive oxygen species (ROS) are important factors in regulating homeostasis in various cells, tissues, and organs. Although ROS are known to cause to muscular disorders, the effects of mitochondrial ROS in muscle physiology have not been fully understood. Here, we investigated the effects of ROS on muscle mass and function using mice deficient in peroxiredoxin 3 (Prx3), which is a mitochondrial antioxidant protein. Ablation of Prx3 deregulated the mitochondrial network and membrane potential of myotubes, in which ROS levels were increased. We showed that the DNA content of mitochondria and ATP production were also reduced in Prx3-KO muscle. Of note, the mitofusin 1 and 2 protein levels decreased in Prx3-KO muscle, a biochemical evidence of impaired mitochondrial fusion. Contractile dysfunction was examined by measuring isometric forces of isolated extensor digitorum longus (EDL) and soleus muscles. Maximum absolute forces in both the EDL and the soleus muscles were not significantly affected in Prx3-KO mice. However, fatigue trials revealed that the decrease in relative force was greater and more rapid in soleus from Prx3-KO compared to wild-type mice. Taken together, these results suggest that Prx3 plays a crucial role in mitochondrial homeostasis and thereby controls the contractile functions of skeletal muscle.