Roles of reactive oxygen species in the corpus luteum

Cells living under aerobic conditions always face the oxygen paradox. Oxygen is necessary for cells to maintain their lives. However, reactive oxygen species such as superoxide radicals, hydroxyl radicals and hydrogen peroxide are generated from oxygen and damage cells. Oxidative stress occurs as a consequence of the excessive production of reactive oxygen species and impaired antioxidant defense systems. Antioxidant enzymes include superoxide dismutase (SOD), which is a specific enzyme to scavenge superoxide radicals; copper‐zinc SOD, located in the cytosol and Mn‐SOD, located in the mitochondria. Both types of SOD belong to the first enzymatic step to scavenge superoxide radicals. It has been reported that a number of local factors such as cytokines, growth factors and eicosanoids are involved in the regulation of the corpus luteum (CL) function in addition to gonadotropins. Since reactive oxygen species are generated and SOD is expressed in the CL, there is a possibility that reactive oxygen species and SOD work as local regulators of the CL function. The present review reports that reactive oxygen species and their scavenging systems play important roles in the regulation of the CL function.     

Addition of erythrocytes to in vitro culture medium attenuates the detrimental effects of reactive oxygen species on bovine preimplantation embryo development

Erythrocytes were recently found to improve the early development of mice embryos by their antioxidant effect. The purpose of the present study was to examine the effect of erythrocytes on the in vitro development of bovine in vitro fertilized (IVF) embryos in medium supplemented with reactive oxygen species (ROS). IVF embryos were cultured in CR1aa medium supplemented with oxidizing agents, 0.5 mmol/L hypoxanthine and 0.01 U/mL xanthine oxidase (HX/XOD), in the presence and absence of erythrocytes (5 × 10⁴, 5 × 10⁵, 5 × 10⁶ and 5 × 10⁷ erythrocytes/mL). After 8 days, blastocysts were examined with a stereomicroscope. HX/XOD blocked development to the blastocyst stage (HX/XOD: 0%, control: 33%), but in the presence of both erythrocytes and HX/XOD, blastocyst development was restored to about one‐third to two‐thirds the normal rate (5 × 10⁵ to 5 × 10⁷ erythrocytes/mL: 12 to 23%). Furthermore, adding erythrocytes or erythrocyte hemolysate to medium without HX/XOD increased the blastocyst rate. These results suggest that the addition of erythrocytes can attenuate the detrimental effects of ROS on embryo development in bovine species as well as in mice.     

Effect of various levels of dissolved oxygen on reactive oxygen species and cryocapacitation‐like changes in bull sperm

The present investigation was carried out to study the effect of various levels of dissolved oxygen (DO) on reactive oxygen species (ROS) and cryocapacitation‐like changes in bull sperm. Egg yolk–Tris–glycerol (EYTG) extender was split into four subextenders; viz., Extender I (control; no flushing with liquid nitrogen (LN₂)), Extender II, Extender III and Extender IV were flushed with LN₂ for 40, 16 and 8 min, respectively. The DO levels were standardized to 11.7, 2, 4 and 8 ppm, respectively, in control (Extender I), Extender II, Extender III and Extender IV. Ejaculates with mass motility of ≥ 3+ were divided into group I (diluted with Extender I), group II (diluted with Extender II), group III (diluted with Extender III) and group IV (diluted with Extender IV) up to 80 × 10⁶ sperm/ml. Extended semen samples were packed in French mini straws (0.25 ml), equilibrated and cryopreserved. Semen samples were evaluated at prefreeze and post‐thaw stage for various parameters (DO, progressive motility (PM), viability (VIB), acrosomal integrity (AI), hypo‐osmotic swelling (HOS) test, ROS, cholesterol (C) and phospholipid (P). The percentage of PM, VIB, AI, HOS test, cholesterol (C) and phospholipid (P) levels, and capacitated sperm were significantly (p < 0.05) higher in groups III and IV as compared to groups I and II. However, the acrosome‐reacted sperm (%; pattern AR) were significantly (p < 0.05) decreased in group III as compared to all other groups. Besides the proportion of sperm displaying tyrosine‐phosphorylated pattern, EA (fluorescence at both equatorial and anterior acrosomal regions, i.e. high capacitation level) was significantly (p < 0.05) reduced in group III compared to all other groups. In conclusion, varying DO levels in the extender significantly affect sperm quality, ROS production and capacitation‐like changes in bulls.     

活性氧非酶促清除剂对老化种子的影响

种子老化是影响种子贮藏的关键问题。活性氧(reactive oxygen species,ROS)非酶促清除剂能延缓种子的老化,但其含量会因种子老化而下降。因此,合理添加ROS非酶促清除剂协助其内部酶系统共同清除种子内ROS,抑制种子的老化,从而延长种子的贮藏寿命,这将成为种质资源迁地保存研究的一个必然发展趋势。本文重点综述了ROS非酶促清除剂的种类及其对种子老化过程的影响,并系统分析了ROS非酶促清除剂在种子老化过程中的研究现状、存在问题及其研究前景,以期为研究种子老化过程中ROS非酶促清除剂的作用机理提供理论基础。     

Feed‐derived volatile basic nitrogen increases reactive oxygen species production of blood leukocytes in lactating dairy cows

The present study investigated over 9 months the changes of fermentative quality of total mixed rations (TMR) containing grass silage (GS) as a major component, associated with changes in the volatile basic nitrogen (VBN) levels in an experimental dairy farm. Effects of VBN levels in TMR on metabolic parameters, reactive oxygen species (ROS) production by blood polymorphonuclear leukocytes (PMNs) and conception rates for dairy cows were analyzed. According to VBN levels in TMR during survey periods, three distinct phases were identified; phase A with low VBN; phase B with high VBN; and phase C with mid‐VBN. Metabolic parameters in blood were all within normal range. However, during phases B and C, nitrogen metabolic indices such as blood urea nitrogen and milk urea nitrogen showed higher levels compared to those in phase A, and a simultaneous increase in ROS production by blood PMNs and the load on hepatic function in metabolic parameters was observed in the cows with a lower conception rate. This suggests that feeding TMR with elevated VBN levels due to poor fermented GS results in stimulation of ROS production by PMNs by ammonia, and negatively affects metabolism and reproductive performance in lactating dairy cow.     

Impact of metritis on the generation of reactive oxygen species by circulating phagocytes and plasma lipopolysaccharide concentration in peripartum dairy cows

This study examined the relationship between postpartum metritis, reactive oxygen species (ROS) generation, and plasma lipopolysaccharide (LPS) concentration in peripartum dairy cows. Blood was collected twice weekly from 2 weeks prepartum through 6 weeks postpartum. Whole blood chemiluminescence (WBCL) was measured using the luminol‐enhanced zymosan‐stimulated chemiluminescence assay. Cows were examined for uterine health disorders and classified into two groups, healthy (n = 11) and metritis (n = 5). Metritis had a significant effect on WBCL, with cows with metritis having a higher WBCL. Plasma LPS concentrations in cows with metritis were significantly higher than in healthy cows. To examine the effect of LPS on WBCL, blood was sampled in healthy peripartum cows (1 to 2 weeks prepartum, n = 8; 0 to 3 weeks postpartum, n = 11; and 4 to 8 weeks postpartum, n = 8) and incubated with LPS. At 1 endotoxin units/mL of LPS, similar to the plasma LPS concentration in cows with metritis, the WBCL increased in cows at 0 to 3 weeks postpartum. Results indicate that the increase in ROS generation and plasma LPS concentration are associated with metritis, and LPS may be responsible for enhanced ROS generation in early postpartum dairy cows.     

Studies on the regulation of seed aging by reactive oxygen species and telomeres

Seeds enable plants to survive in harsh environmental conditions and can transmit genetic information from their parents to the next generation. Seed vigor is an important character in agriculture,which directly affects the field emergence rate and crop yield. However,due to seed aging,seed vigor decreased during storage. In order to effectively protect genetic resources and reduce the huge economic losses caused by seed aging to agricultural production,it is necessary to explore the mechanism of seed aging in order to understand the causes of seed aging and a series of important events that occur in the aging process. During seed storage,high temperature and humidity are the two main factors to accelerate seed aging. The oxidative damage caused by reactive oxygen species（ROS）is the main reason. ROS can interact with any biological macromolecule,leading to protein damage,lipid peroxidation,chromosomal telomere structure abnormality and various cell components damage caused by DNA damage. In addition,ROS may also induce programmed cell death,leading to seed aging. At the initial stage of imbibition,the seeds will repair some damage,but if they cause great damage to key structures,they will fail to repair,and the seeds will lose their vitality permanently,so they cannot germinate normally in a relatively short time. The exact mechanism of seed aging has not been fully studied. Based on this,this study mainly reviewed the generation and elimination of ROS during seed aging,the influence of ROS on biological macromolecules,the response of chromosome telomere system to seed aging,and the research progress of genes related to seed aging,which is of great significance for understanding the causes of seed aging and analyzing the mechanism of seed aging. © 2023 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

一氧化氮对水分胁迫下小麦叶片活性氧代谢及膜脂过氧化的影响

着重探讨了在水分胁迫条件下,一氧化氮对小麦叶片膜脂过氧化的影响。试验结果表明,低浓度的NO能够提高小麦叶片中抗氧化酶的活性,消除自由基,从而缓解水分胁迫造成的细胞膜脂过氧化损伤,而高浓度的一氧化氮降低了抗氧化酶的活性,使自由基的产生量增加,从而加重了膜的损伤。     

干旱胁迫对金心吊兰叶片活性氧及其清除系统的影响

以金心吊兰叶片边缘的绿色区域与中心黄白色区域为材料,研究了干旱胁迫对其活性氧及其清除系统的影响,结果表明,1)随着胁迫时间的延长,叶片各区域的过氧化氢(H₂O₂)、超氧阴离子(O₂^-·)含量和丙二醛(MDA)含量均表现出逐渐上升的趋势,而超氧化物歧化酶(SOD)与过氧化物酶(POD)活性则先上升后下降。2)随着胁迫浓度的增加,叶片中活性氧(H₂O₂,O₂^-·)含量、抗氧化酶(SOD,POD)活性和MDA含量表现出上升的趋势。3)采用隶属函数法对吊兰叶片的抗旱性进行了综合评价,其抗旱性表现出位置效应,叶片中心区域抗旱性强于边缘区域。4)吊兰叶片的抗旱性与叶绿素含量呈负相关,叶绿素含量相对高的区域其抗旱性相对较低,金心吊兰抗旱性强于野生型。     

外源水杨酸对干旱胁迫下小冠花叶片活性氧水平及抗氧化系统的影响

本研究以小冠花幼苗叶片为材料,用0.25,0.5,1和2 mmol/L外源水杨酸(SA)对植株进行叶面喷施,通过盆栽模拟干旱胁迫处理,测定幼苗叶片在连续干旱下膜脂过氧化指标、抗氧化酶活性和非酶抗氧化物含量,研究外源水杨酸对干旱胁迫下小冠花幼苗活性氧水平及抗氧化系统的影响。结果表明,0.5~2.0 mmol/L的水杨酸显著降低了干旱胁迫下小冠花叶片中超氧阴离子(O₂^-·)的产生速率、过氧化氢(H₂O₂)含量、丙二醛(MDA)含量及细胞膜透性,显著提高了过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性,提升了抗氧化指数,但对抗坏血酸(ASA)和谷胱甘肽(GSH)含量的影响不显著。在干旱胁迫第11天,1 mmol/L SA处理的小冠花叶片O₂^-·产生速率、MDA含量、细胞膜透性显著低于干旱处理79.78%,34.42%,36.96%(P<0.05);CAT酶活性显著高于干旱处理2.45倍(P<0.05);到干旱胁迫第 16天,SOD、POD酶活性比干旱处理提高了3.85和3.63倍。表明外源水杨酸能够降低干旱胁迫下小冠花叶片的活性氧水平,提高小冠花叶片抗氧化能力,缓解干旱胁迫造成的细胞膜脂过氧化损伤,提高了小冠花的抗旱性,尤其以1 mmol/L水杨酸效果最佳。     

Epigallocatechin-3-gallate suppresses hemin-aggravated colon carcinogenesis through Nrf2-inhibited mitochondrial reactive oxygen species accumulation

BackgroundPrevious studies have presented evidence to support the significant association between red meat intake and colon cancer, suggesting that heme iron plays a key role in colon carcinogenesis. Epigallocatechin-3-gallate (EGCG), the major constituent of green tea, exhibits anti-oxidative and anti-cancer effects. However, the effect of EGCG on red meat-associated colon carcinogenesis is not well understood.ObjectivesWe aimed to investigate the regulatory effects of hemin and EGCG on colon carcinogenesis and the underlying mechanism of action.MethodsHemin and EGCG were treated in Caco2 cells to perform the water-soluble tetrazolium salt-1 assay, lactate dehydrogenase release assay, reactive oxygen species (ROS) detection assay, real-time quantitative polymerase chain reaction and western blot. We investigated the regulatory effects of hemin and EGCG on an azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced colon carcinogenesis mouse model.ResultsIn Caco2 cells, hemin increased cell proliferation and the expression of cell cycle regulatory proteins, and ROS levels. EGCG suppressed hemin-induced cell proliferation and cell cycle regulatory protein expression as well as mitochondrial ROS accumulation. Hemin increased nuclear factor erythroid-2-related factor 2 (Nrf2) expression, but decreased Keap1 expression. EGCG enhanced hemin-induced Nrf2 and antioxidant gene expression. Nrf2 inhibitor reversed EGCG reduced cell proliferation and cell cycle regulatory protein expression. In AOM/DSS mice, hemin treatment induced hyperplastic changes in colon tissues, inhibited by EGCG supplementation. EGCG reduced the hemin-induced numbers of total aberrant crypts and malondialdehyde concentration in the AOM/DSS model.ConclusionsWe demonstrated that EGCG reduced hemin-induced proliferation and colon carcinogenesis through Nrf2-inhibited mitochondrial ROS accumulation.     

Intracellular reactive oxygen species production by polymorphonuclear leukocytes in bovine leukemia virus-infected dairy cows

The present study assesses the oxidative burst activity from polymorphonuclear leukocytes (PMNLs) from bovine leukemia virus (BLV)-infected cows. Fifteen clinically healthy cows were divided into serologically positive cows without any hematological alteration, serologically positive animals with persistent lymphocytosis (PL) and healthy serologically negative cows. The oxidative burst activity from the PMNLs was evaluated by flow cytometry using 2',7'-dichlorofluorescein diacetate as a probe. PMNLs from each cow were incubated with heat-killed Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) to stimulate oxidative burst activity. The results of the present work showed no significant difference in the oxidative burst activity without any stimulus and elicited by S. aureus. Conversely, a decrease in the oxidative burst index induced by E. coli in PMNLs was observed in BLV-infected cows.     

Effect of pterostilbene on development,equatorial lipid accumulation and reactive oxygen species production of in vitro-produced bovine embryos

The pterostilbene (PT) molecule is a phytoalexin with a reducing effect on reactive oxygen species (ROS) and with a capacity to block lipogenesis. However, the potential reducing effects of PT on equatorial lipid accumulation and ROS have not yet been elucidated for in vitro-derived bovine embryos. The present study evaluated the effects of concentrations of 3, 1, 0.33, 0.11 μM PT, and a vehicle group on the percentage of cleaved embryos, embryos with more than 6 cells, percentage of blastocyst on Day 7 and 8, percentage of transferable embryos on Day 7, the cell count and relative concentration of lipids. In the second experiment, the effects of 0.33 μM PT and a vehicle group within two different O₂ environments (5% and 20%) were evaluated for ROS generation and the percentage of Day 8 blastocysts. In the first experiment, no significant differences were found between the treatments with PT and the vehicle group (p > .05) concerning the percentage of cleaved embryos and embryos with more than 6 cells. Lipid reduction was observed in the groups treated with PT versus the vehicle group (p < .05). The vehicle group showed a higher rate of blastocyst production on Days 7 and 8 (p < .05) and an increase in the percentage of transferable embryos on Day 7 compared to the PT treatment groups (p < .05). Cell counts were not significantly different between treatments with PT and the vehicle group (p > .05). In the second experiment, the O₂ concentration did not significantly affect ROS generation (p > .05); however, the groups treated with PT (0.33 μM) had a reduction in ROS (p < .05). The O₂ concentration also did not significantly affect the rate of blastocyst production on Day 8 (p = .7696). Future research should be conducted to ascertain whether the reduction of lipids could enhance the cryopreservation and post-thaw viability of PT-treated embryos.     

Melatonin reduces apoptotic cells,SOD2 and HSPB1 and improves the in vitro production and quality of bovine blastocysts

Effects of adding different concentrations of melatonin (10^?7, 10^?9 and 10^?11 M) to maturation (Experiment 1; Control, IVM  + 10^?7, IVM  + 10^?9, IVM  + 10^?11) and culture media (Experiment 2; Control, IVC  + 10^?7, IVC  + 10^?9, IVC  + 10^?11) were evaluated on in vitro bovine embryonic development. The optimal concentration of melatonin (10^?9 M) from Experiments 1–2 was tested in both maturation and/or culture media of Experiment 3 (Control, IVM  + 10^?9, IVC  + 10^?9, IVM /IVC  + 10^?9). In Experiment 1, maturated oocytes from Control and IVM  + 10^?9 treatments showed increased glutathione content, mitochondrial membrane potential and percentage of Grade I blastocysts (40.6% and 43%, respectively). In Experiment 2, an increase in the percentage of Grade I blastocysts was detected in IVC  + 10^?7 (43.5%; 56.7%) and IVC  + 10^?9 (47.4%; 57.4%). Moreover, a lower number and percentage of apoptotic cells in blastocysts were observed in the IVC  + 10^?9 group compared to Control (3.8 ± 0.6; 3.6% versus 6.1 ± 0.6; 5.3%). In Experiment 3, the IVC  + 10^?9 treatment increased percentage of Grade I blastocysts with a lower number of apoptotic cells compared to IVM /IVC  + 10^?9 group (52.6%; 3.0 ± 0.5 versus 46.0%; 5.4 ± 1.0). The IVC  + 10^?9 treatment also had a higher mRNA expression of antioxidant gene (SOD 2) compared to the Control, as well as the heat shock protein (HSPB 1) compared to the IVM  + 10^?9. Reactive oxygen species production was greater in the IVM /IVC  + 10^?9 treatment group. In conclusion, the 10^?9 M concentration of melatonin and the in vitro production phase in which it is used directly affected embryonic development and quality.     

Evaluation of assays for the measurement of bovine neutrophil reactive oxygen species

During mastitis and other bacterial-mediated diseases of cattle, neutrophils play a critical role in the host innate immune response to infection. Neutrophils are among the earliest leukocytes recruited to the site of infection and contribute to host innate immune defenses through their ability to phagocytose and kill bacteria. The bactericidal activity of neutrophils is mediated, in part, through the generation of reactive oxygen species (ROS). Extracellular release of ROS can induce injury to host tissue as well, and aberrant release of ROS has been implicated in the pathogenesis of certain inflammatory-mediated diseases. Due to their essential role in bacterial clearance and implicated involvement in the pathogenesis of other diseases, there is much interest in the study of neutrophil-generated ROS. Several assays have been developed to measure ROS production, however, many of these have not been evaluated with bovine neutrophils. The objectives of the current study were to evaluate different assays capable of measuring bovine neutrophil ROS, and to compare the results of assays never previously tested with bovine neutrophils to those obtained from more well-established assays frequently used with these cells. Eight different assays were evaluated, including: luminol, isoluminol, and methyl cypridina luciferin analog (MCLA) chemiluminescence assays; Amplex Red, dihydroethidium (DHE), dichlorodihydrofluorescein diacetate (CM-H(2)DCFDA), and dihydrorhodamine 123 fluorescence assays; and the cytochrome c absorbance assay. The assays were evaluated in the context of their abilities to detect ROS produced in response to two agonists commonly used to induce neutrophil activation, phorbol 12-myristate, 13-acetate (PMA) and opsonized zymosan. Diphenyleneiodonium chloride, a NADPH oxidase inhibitor, was used to assess the specificity of the assays to detect ROS. The ability of these assays to discriminate between intra- and extracellular ROS and to specifically detect distinct ROS was evaluated using superoxide dismutase and catalase, which scavenge extracellular superoxide and hydrogen peroxide, respectively. With the exception of the DHE assay, all assays detected bovine neutrophil ROS generation elicited by PMA and zymosan. PMA, but not zymosan, was able to stimulate neutrophil generation of ROS at levels that were detectable with DHE. The MCLA chemiluminescence assay was the only assay that detected ROS produced in response to each of the lowest concentrations of PMA and zymosan tested. To our knowledge, this is the first study to evaluate DHE-, MCLA-, Amplex Red-, and isoluminol-based assays for the measurement of bovine neutrophil ROS, and the most comprehensive comparative study of ROS assays under similar experimental conditions.     

The effect of various Mycoplasma bovis isolates on bovine leukocyte responses

Mycoplasma bovis (M. bovis) contributes to a number of clinical syndromes in cattle; in particular, chronic pneumonia that is poorly responsive to therapy has been increasingly recognized as an important cause of morbidity, mortality, and financial loss. M. bovis impairs host immune function, but little is known about whether field isolates vary significantly in their effect on immune function. This research tested the hypothesis that different field isolates vary in their ability to suppress cellular metabolism and cellular production of radical oxygen species (ROS) by bovine leukocytes. Total blood leukocytes from 6 cattle were exposed to six field isolates, two diagnostic lab isolates, and two high passage laboratory isolates of M. bovis, and ROS production was measured by oxidation of dihydrorhodamine 123 (DHR-123). Cellular metabolism was measured by reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Significant differences in the response to some field isolates were identified. Three field isolates and both diagnostic lab isolates significantly decreased ROS production by leukocytes from multiple cattle, while the high pass laboratory isolates did not. In contrast, MTT reduction was not significantly impaired by any of the M. bovis strains tested. M. bovis impairs ROS production by bovine leukocytes; the magnitude of the effect appears to be isolate-dependent, and is not related to a general impairment of cellular metabolism. Chronic M. bovis infection in some cattle may be related to impaired ability of leukocytes to produce ROS when exposed to M. bovis.     

Effect of magnesium on reactive oxygen species production in the thigh muscles of broiler chickens

1. The objective of the present study was to investigate the effect of magnesium (Mg) on reactive oxygen species (ROS) production in the thigh muscles of broiler chickens. A total of 96 1-d-old male Arbor Acre broiler chickens were randomly allocated into two groups, fed either on low-Mg or control diets containing about 1.2 g/kg or 2.4 g Mg/kg dry matter. 2. The low-Mg diet significantly increased malondialdehyde (MDA) concentration and decreased glutathione (GSH) in the thigh muscles of broiler chickens. ROS production in the thigh muscle homogenate was significantly higher in the low-Mg group than in the control group. Compared with the control, muscle Mg concentration of broiler chickens from the low-Mg group decreased by 9.5%. 3. Complex II and III activities of the mitochondrial electron transport chain in broilers on low-Mg diet increased by 23 and 35%, respectively. Significant negative correlations between ROS production and the activities of mitochondrial electron transport chain (ETC) complexes were observed. 4. The low-Mg diet did not influence contents of iron (Fe) or calcium (Ca) in the thigh muscles of broiler chickens and did not influence unsaturated fatty acid composition (except C18:2) in the thigh muscles. 5. A low-Mg diet decreased Mg concentration in the thigh muscles of broiler chickens and then induced higher activities of mitochondrial ETC, consequently increasing ROS production. These results suggest that Mg modulates the oxidation-anti-oxidation system of the thigh muscles at least partly through affecting ROS production.     

The suppressive effect of dietary coenzyme Q10 on mitochondrial reactive oxygen species production and oxidative stress in chickens exposed to heat stress

This study was conducted to determine if dietary supplementation with coenzyme Q₁₀ (CoQ₁₀), which can act as a potent antioxidant and is an obligatory cofactor of mitochondrial uncoupling protein, suppresses the heat stress (HS)‐induced overproduction of mitochondrial reactive oxygen species (ROS) and oxidative damage in the skeletal muscle of birds. The carbonyl protein content of skeletal muscle was significantly higher in birds exposed to HS treatment (34°C, 12 h) than in thermoneutral birds (25°C). This increase was suppressed by CoQ₁₀ supplementation (40 mg/kg diet). Succinate‐supported mitochondrial ROS production was increased by HS treatment, and this increase was also suppressed by CoQ₁₀ supplementation. In contrast, CoQ₁₀ supplementation did not affect the HS‐induced decrease in mitochondrial proton leak. The mitochondrial membrane potential (ΔΨ), to which HS‐induced ROS production was previously shown to be sensitive, tended to be increased by HS treatment, but this rise in ΔΨ was not affected by CoQ₁₀ supplementation. Taken together, these results suggest that dietary CoQ₁₀ supplementation attenuates HS‐induced oxidative damage to skeletal muscle, by preventing the overproduction of succinate‐supported mitochondrial ROS in a manner that is independent of ΔΨ. © 2015 Japanese Society of Animal Science