Catalase Protein Expression Research Articles

Astaxanthin attenuates acute cerebral infarction via Nrf-2/HO-1 pathway in rats

ObjectiveAcute cerebral infarction (ACI) is susceptible to cause disability or death of people. Astaxanthin (ATX) possesses the protective effect of organ injury. Therefore, the study was to explore the potential mechanism of protective effect with ATX on ACI. Methods30 SD rats were divided into Sham, ACI, and ATX groups. The rats in the ATX group were pretreated with ATX by gavage for three days before surgery, while the rats in the other two groups were pretreated with saline. The model of ACI was established by thread embolization. 24 h after the operation, the neurological function was scored, and cerebral infarct area and pathological morphology of brains were measured; the edema of the brain was detected by dry/wet method; Western blot was applied to measure the translocation of Nrf-2 and the protein expression of HO-1, Bax and BCL-2; Brain cell apoptosis was assessed through TUNEL; ELISA was used to detect the oxidative stress factors of catalase (CAT) superoxide dismutase (SOD), glutathione peroxidase (GPX) and malondialdehyde (MDA), and the inflammatory factors of TNF-α, IL-1β, IL-6. ResultCompared with the ACI group, ATX pretreatment can significantly improve neurological function; reduce the edema index of the brain, cerebral infarct area, cerebral pathological damage and apoptosis of brain cells. Moreover, ATX also can increase the protein expression of nuclear Nrf-2, HO-1, BCL-2, CAT, SOD, and GPX by decreasing the content of TNF-α, IL-1β, IL-6, MDA, Bax and cytosolic Nrf-2. ConclusionATX might have a protective effect of acute cerebral infarction, and the mechanism is probably associated with suppressing oxidative stress, inflammation, and apoptosis by activating Nrf-2/HO-1signalling.

Melatonin Protects Goat Spermatogonial Stem Cells against Oxidative Damage during Cryopreservation by Improving Antioxidant Capacity and Inhibiting Mitochondrial Apoptosis Pathway

Spermatogonial stem cells (SSCs) are the only adult stem cells that pass genes to the next generation and can be used in assisted reproductive technology and stem cell therapy. SSC cryopreservation is an important method for the preservation of immature male fertility. However, freezing increases the production of intracellular reactive oxygen species (ROS) and causes oxidative damage to SSCs. The aim of this study was to investigate the effect of melatonin on goat SSCs during cryopreservation and to explore its protective mechanism. We obtained SSCs from dairy goat testes by two-step enzymatic digestion and differential plating. The SSCs were cryopreserved with freezing media containing different melatonin concentrations. The results showed that 10−6 M of melatonin increased significantly the viability, total antioxidant capacity (T-AOC), and mitochondrial membrane potential of frozen-thawed SSCs, while it reduced significantly the ROS level and malondialdehyde (MDA) content (P < 0.05). Further analysis was performed by western blotting, flow cytometry, and transmission electron microscopy (TEM). Melatonin improved significantly the enzyme activity and protein expression of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) (P < 0.05), thereby activating the antioxidant defense system of SSCs. Furthermore, melatonin inhibited significantly the expression of proapoptotic protein (Bax) and increased the expression of antiapoptotic proteins (Bcl-2 and Bcl-XL) (P < 0.05). The mitochondrial apoptosis pathway analysis showed that the addition of melatonin reduced significantly the mitochondrial swelling and vacuolation, and inhibited the release of cytochrome C from mitochondria into the cytoplasm, thereby preventing the activation of caspase-3 (P < 0.05) and inhibiting SSC apoptosis. In addition, melatonin reduced significantly the autophagosome formation and regulated the expression of autophagy-related proteins (LC3-I, LC3-II, P62, Beclin1, and ATG7) (P < 0.05), thereby reversing the freeze-induced excessive autophagy. In summary, melatonin protected goat SSCs during cryopreservation via antioxidant, antiapoptotic, and autophagic regulation.

Alginate Oligosaccharide Prevents against D-galactose-mediated Cataract in C57BL/6J Mice via Regulating Oxidative Stress and Antioxidant System

ABSTRACT Purpose Alginate oligosaccharides (AOS), obtained from depolymerizing alginate, has multiple pharmacological benefits. Cataract is a common disease caused by turbidity of the lens protein due to lens metabolism disorders. This study aimed to test the effects and the underlying mechanisms of AOS on D-galactose (D-gal)-mediated cataract. Materials and Methods A total of 45 8-week-old C57BL/6 J male mice were randomly divided into 5 groups. After eight weeks’ intervention, the score of cataract was calculated depending on the turbidity of the lens. Hematoxylin and eosin (HE) and transmission electron microscope (TEM) images were observed. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) level were measured by corresponding detection kits, respectively. SOD1, SOD2, catalase (CAT) and p53 protein expressions were examined by Western blot. Nuclear factor erythroid-2 related factor (Nrf2) and heme oxygenase-1 (HO-1) mRNA expressions were examined by Quantitative Real Time-PCR (RT-qPCR). Results The score of the turbidity of the lens showed that AOS significantly delayed the cataractogenesis. HE staining and TEM imaging showed that AOS decreased the damage and senescence of lenses in D-gal-induced C57BL/6 J mice. We further detected aging marker p53 expression in crystalline lenses, and our result showed that AOS significantly inhibited p53 protein expression in D-gal-induced mice. In addition, SOD activity and MDA level detection results showed that AOS significantly increased the activity of SOD, and decreased the level of MDA in crystalline lenses homogenates of D-gal-induced aging mice. Western blot results showed that AOS attenuated the damage of D-gal in the protein expressions of antioxidative enzymes SOD1, SOD2 and CAT. RT-qPCR results showed that AOS suppressed the down-regulation of Nrf2 and HO-1 mRNA expressions induced by D-gal. Conclusions AOS prevents against D-gal-mediated cataract in C57BL/6 J mice via inhibiting oxidative stress and up-regulating antioxidant system. Consequently, our results suggest that AOS may be an effective therapeutic strategy against cataract.

Inclusion of condensed tannins in Lateolabrax japonicus diets: Effects on growth, nutrient digestibility, antioxidant and immune capacity and copper sulphate stress resistance

Condensed tannins (CT) possess antioxidant and immunostimulatory activities and thereby are regarded as a promising alternative to in-feed antibiotics. Although the effect of CT on growth of fish has been evaluated, little information is available about the effect of CT on the oxidative stress resistance of Lateolabrax japonicus. This study was conducted to assess the effects of CT on growth, nutrient digestibility, antioxidant and immune capacity and copper sulphate stress resistance of L. japonicus. A total of 960 juvenile L. japonicus (5.5 ± 0.11 g body weight) were randomly allocated into six groups with four replicates each (40 fish per replicate) and fed six diets containing 0, 0.2, 0.4, 0.6, 0.8 and 1.0 g/kg of grape seed CT respectively for 56 d. Fish were fed to apparent satiation twice daily during the entire experimental period and feces were collected daily for the last 14 d of feeding trial to determine nutrients digestibility using yttrium oxide as an indigestible marker. Fish were suffered with a 3-h acute copper sulphate stress test at the end of feeding trial. Blood and liver samples were collected to analyze antioxidant enzymes and non-specific immune indices, histomorphology and antioxidant-related genes expression. Dietary CT did not affect growth, body composition, liver histological appearance of fish but linearly decreased (P < 0.05) the intraperitoneal fat ratio, serum total cholesterol, triacylglycerol and tumor necrosis factor α as dietary CT increasing from 0 to 1 g/kg. Dry matter digestibility was linearly and quadratically decreased (P < 0.001), whereas digestibilities of organic matter, crude protein, crude lipid and ash were similar (P> 0.05) among treatments. Total antioxidant capacity (TAOC) and catalase (CAT) in serum as well as superoxide dismutase (SOD) and glutathione S-transferase in the liver were linearly increased (P < 0.01), and serum SOD and liver TAOC were linearly and quadratically increased (P < 0.05), whereas liver interleukin 6 was linearly decreased (P < 0.001) with the increased dietary CT concentrations. Expressions of SOD and nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA were up-regulated (P < 0.05) as dietary CT increasing, whereas expression of CAT and heat shock protein 70 (HSP70) mRNA were not affected by the treatments. Fish fed diets containing 0.8–1.0 g/kg of CT had lower (P < 0.05) cumulative mortality rate than those fed other diets as observed in the acute copper sulphate stress test. Superoxide dismutase and glutathione peroxidase in serum and TAOC and CAT in the liver were linearly increased (P < 0.05), liver CAT and Nrf2 mRNA were up-regulated (P < 0.05), whereas HSP70 mRNA was down-regulated (P < 0.05) with increased dietary CT concentrations. Dietary grape seed CT up to 1 g/kg did not affect growth and nutrient digestibility, but enhanced antioxidant and immune capacity as well as copper sulphate stress resistance of juvenile L. japonicus probably by activating Nrf2 signaling pathway. Condensed tannins are beneficial for the lipid metabolism of L. japonicus owing to decreased intraperitoneal fat ratio and blood lipid.

Prolonged treatment with a PI3K p110α inhibitor causes sex- and tissue-dependent changes in antioxidant content, but does not affect mitochondrial function.

Genetic inhibition of the p110α isoform of phosphatidylinositol-3-kinase (PI3K) can increase murine lifespan, enhance mitochondrial function and alter tissue-specific oxidative balance. Here, we investigated whether pharmacological inhibition of the p110α isoform of PI3K induces similar enhancement of mitochondrial function in middle-aged mice. Eight-month-old male and female mice were fed a diet containing 0.3 g/kg of the p110α-selective inhibitor BYL-719 (BYL) or a vehicle diet (VEH) for 6 weeks. Mice consuming BYL-719 had higher blood glucose and insulin, and tended towards decreased body weight. After 72 h, gene expression of the mitochondrial biogenesis mediators Pgc1α, Tfam and Nrf1 was greater in liver of BYL-719 males only, but unchanged in skeletal muscle of either sex. Six weeks of BYL-719 treatment did not affect mitochondrial content or function in the liver or skeletal muscle of either sex. In livers of males only, the expression of the antioxidant genes Nfe2l2, Cat, Sod1 and Sod2 increased within 72 h of BYL-719 treatment, and remained higher after 6 weeks. This was associated with an increase in hepatic GSH content and catalase protein expression, and lower H2O2 levels. Our results suggest that pharmacological inhibition of p110α in adult mice does not affect liver or skeletal muscle mitochondrial function, but does show sex- and tissue-specific effects on up-regulation of antioxidant response.

RGFP966 inactivation of the YAP pathway attenuates cardiac dysfunction induced by prolonged hypothermic preservation.

Oxidative stress and apoptosis are the key factors that limit the hypothermic preservation time of donor hearts to within 4-6 h. The aim of this study was to investigate whether the histone deacetylase 3 (HDAC3) inhibitor RGFP966 could protect against cardiac injury induced by prolonged hypothermic preservation. Rat hearts were hypothermically preserved in Celsior solution with or without RGFP966 for 12 h followed by 60 min of reperfusion. Hemodynamic parameters during reperfusion were evaluated. The expression and phosphorylation levels of mammalian STE20-like kinase-1 (Mst1) and Yes-associated protein (YAP) were determined by western blotting. Cell apoptosis was measured by the terminal deoxynucleotidyl-transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) method. Addition of RGFP966 in Celsior solution significantly inhibited cardiac dysfunction induced by hypothermic preservation. RGFP966 inhibited the hypothermic preservation-induced increase of the phosphorylated (p)-Mst1/Mst1 and p-YAP/YAP ratios, prevented a reduction in total YAP protein expression, and increased the nuclear YAP protein level. Verteporfin (VP), a small molecular inhibitor of YAP-transcriptional enhanced associate domain (TEAD) interaction, partially abolished the protective effect of RGFP966 on cardiac function, and reduced lactate dehydrogenase activity and malondialdehyde content. RGFP966 increased superoxide dismutase, catalase, and glutathione peroxidase gene and protein expression, which was abolished by VP. RGFP966 inhibited hypothermic preservation-induced overexpression of B-cell lymphoma protein 2 (Bcl-2)-associated X (Bax) and cleaved caspase-3, increased Bcl-2 mRNA and protein expression, and reduced cardiomyocyte apoptosis. The antioxidant and anti-apoptotic effects of RGFP966 were cancelled by VP. The results suggest that supplementation of Celsior solution with RGFP966 attenuated prolonged hypothermic preservation-induced cardiac dysfunction. The mechanism may involve inhibition of oxidative stress and apoptosis via inactivation of the YAP pathway.

The impact of non-toxic blue light (453 nm) on cellular antioxidative capacity, TGF-β1 signaling, and myofibrogenesis of human skin fibroblasts

Studies have demonstrated that blue light induces biological effects, such as cell death, and inhibition of proliferation and differentiation. Since blue light at longer wavelength (>440 nm) exerts less injurious effects on cells than at shorter wavelengths, (400–440 nm), we have investigated the impact of non-toxic (LED) blue light at 453 nm wavelength on human skin fibroblasts (hsFBs). We found that besides its decreasing effects on the proliferation rate, repeated blue light irradiations (80 J/cm2) also significantly reduced TGF-β1-induced myofibrogenesis as shown by diminished α-SMA and EDA-FN expression accompanied by reduced protein expression and phosphorylation of ERK 1/2, SMAD 2/3, and p38—key players of TGF-β1-induced myofibrogenesis. In parallel, catalase protein expression, intracellular FAD concentrations as well as NADP+/NADPH ratio were reduced, whereas intracellular reactive oxygen species (ROS) were increased. We postulate that as a molecular mechanism downregulation of catalase and photoreduction of FAD induce intracellular oxidative stress which, in turn, affects the signaling factors of myofibrogenesis leading to a lower rate of α-SMA and EDA-FN expression and, therefore, myofibroblast formation. In conclusion, blue light even at longer wavelengths shows antifibrotic activity and may represent a suitable and safe approach in the treatment of fibrotic skin diseases including hypertrophic scarring and scleroderma.

Doxorubicin‑induced oxidative and nitrosative stress: Mitochondrial connexin 43 is at the crossroads.

Oxidative stress is widely accepted as a key factor of doxorubicin (Doxo)-induced cardiotoxicity. There is evidence to indicate that nitrosative stress is involved in this process, and that Doxo interacts by amplifying cell damage. Mitochondrial connexin 43 (mitoCx43) can confer cardioprotective effects through the reduction of mitochondrial reactive oxygen species production during Doxo-induced cardiotoxicity. The present study aimed to evaluate the involvement of mitoCx43 in Doxo-induced nitrosative stress. Rat H9c2 cardiomyoblasts were treated with Doxo in the absence or presence of radicicol, an inhibitor of Hsp90, the molecular chaperone involved in Cx43 translocation to the mitochondria that underlies its role in cardioprotection. FACS analysis and RT-qPCR revealed that Doxo increased superoxide dismutase, and catalase gene and protein expression. As shown by hypodiploid nuclei and confirmed by western blot analysis, Doxo increased caspase 9 expression and reduced procaspase 3 levels, which induced cell death. Moreover, a significant increase in the activation of the NF-κB signaling pathway was observed. It is well known that the increased expression of inducible nitric oxide synthase results in nitric oxide overproduction, which then rapidly reacts with hydrogen peroxide or superoxide generated by the mitochondria, to form highly reactive and harmful peroxynitrite, which ultimately induces nitrotyrosine formation. Herein, these interactions were confirmed and increased effects were observed in the presence of radicicol. On the whole, the data of the present study indicate that an interplay between oxidative and nitrosative stress is involved in Doxo-induced cardiotoxicity, and that both aspects are responsible for the induction of apoptosis. Furthermore, it is demonstrated that the mechanisms that further increase mitochondrial super-oxide generation (e.g., the inhibition of Cx43 translocation into the mitochondria) significantly accelerate the occurrence of cell death.

Whey protein boosts the antioxidant profile of rats by enhancing the activities of crucial antioxidant enzymes in a tissue-specific manner

Whey protein, a by-product of cheese industry, is harmful for the environment (i.e., surface and subterranean waters, soil) and, therefore, for humans due to its high polluting burden. Concomitantly, it has been reported that it is a mixture with potent antioxidant action since it is rich in cysteine residues, which are necessary for glutathione synthesis in vivo. On this basis, this study intended to examine the role of whey protein on the intensification of tissue antioxidant arsenal. To this end, a dose of sheep/goat whey protein equal to 1 g/kg of body weight/day dissolved in drinking water was administered to rats for 28 consecutive days. According to our findings, whey protein improved the antioxidant profile of liver, small intestine, lung and muscle whereas it did not affect the redox state of kidney. Our results were based on the alterations found in the protein expression of glutamate cysteine ligase, catalase and superoxide dismutase-1 measured in all tissues and the activity of glutathione S-transferase evaluated in muscle. Although tissue-specific, it is obvious that the action of whey protein is biologically beneficial and could serve as a biofunctional constituent for foods able to improve redox profile when administered against redox-related diseases.

Effects of starvation and subsequent re-feeding on intestinal microbiota, and metabolic responses in Nile tilapia, Oreochromis niloticus

The effects of starvation and re-feeding on Nile tilapia (Oreochromis niloticus) remain incompletely understood so far. In this study, the changes of intestinal microbiota, the metabolic and immune (antioxidant) responses of Nile tilapia (Oreochromis niloticus) during starvation and re-feeding stages were investigated. The metabolic responses (cortisol, ALT, AST, and leptin) and immune responses (hsp70, SOD, and CAT) were measured. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the starvation group significantly increased during starvation and decrease after re-feeding. Cortisol levels increase during starvation and decreased after re-feeding. During starvation, the mRNA expression of superoxide dismutase (SOD), catalase (CAT), and heat shock protein (hsp70) were up-regulated while leptin was down-regulated. The microbial taxonomic composition of the starvation group slightly increased from the feeding and re-feeding groups. The relative abundance of the top five bacterial phyla in the intestinal of Nile tilapia (feeding, starvation and re-feeding groups) were Fusobacteria, Proteobacteria, Firmicutes, Bacteriodetes, and Actinobacteria. The relative abundance of the top three intestinal bacterial genera of Nile tilapia (feeding, starvation and re-feeding groups) were Cetobacterium, Romboutsia, Plesiomonas, Bacteroides, and Clostridium senso stricto. Taken together, starvation and re-feeding can modulate the diversity of microbial communities, the metabolic and immune responses of Nile tilapia.

Improvement of Flavonoids in Lemon Seeds on Oxidative Damage of Human Embryonic Kidney 293T Cells Induced by H2O2.

In this study, flavonoids in lemon seeds (FLS) were used to assess its improvement on the oxidative damage of human embryonic kidney 293T cells (HEK 293T cells) induced by H2O2. In vitro experiments showed that the survival rates of HEK 293T cells treated with different flavonoid concentrations (50 μg/mL, 100 μg/mL, and 150 μg/mL) exceeded 95%, indicating no significant toxic effect. Compared with the normal group, H2O2 (0.3 mmol/L) resulted significantly in oxidative stress injury of HEK 293T cells. The survival rate of the damaged cells increased after treatment with flavonoids, and the survival rate of cells treated with a high concentration (150 μg/mL) of flavonoids was 76.2%. Flavonoids also effectively inhibited H2O2-induced apoptosis. At the same time, flavonoid treatment significantly reduced the malondialdehyde content in cells and increased the levels of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and glutathione peroxidase (GSH-Px). Quantitative polymerase chain reaction (qPCR) and Western blot analysis also suggested that FLS upregulated mRNA and protein expressions of CAT, SOD (SOD1, SOD2), GSH (GSH1), and GSH-Px in H2O2-induced oxidative damage of HEK 293T cells. The high-performance liquid chromatography analysis demonstrated that FLS contained six compounds, including gallocatechin, caffeic acid, epicatechin, vitexin, quercetin, and hesperidin. FLS were proven to have a good antioxidant capacity in vitro and improve significantly the oxidative damage of HEK 293T cells induced by H2O2. The biological activity value warrants investigation in additional studies.

Long Term Effects of Low Dose Radiation Exposure During Late Gestation on Cardiac Metabolism and Oxidative Stress

An adverse in utero environment can result in fetal programming that can manifest as diseases later in life. Ionizing radiation (IR) is known to cause detrimental fetal programming especially during organogenesis. High doses of radiation cause severe cellular damage that can lead to mortality, however, the physiological effects of low dose radiation are not fully understood. This study examines the effect of low to non‐lethal radiation exposure during late gestation on cardiac metabolism and oxidative stress in adult mice. Pregnant C57BL/6J mice were exposed to 50, 300, or 1000mGy of gamma radiation or were sham irradiated on gestational day 15. At 4 months of age, 18FDG uptake was observed using PET imaging as an indicator of cardiac glucose uptake. Western blot was used to determine changes in 4‐hydroxynonenal adduct formation, catalase, superoxide dismutase (SOD), and glutathione peroxidase (GPx) protein expression and catalase, SOD and GPx enzyme activity was measured. Both male and female irradiated pups had lower body weights when compared to the sham group. Female pups receiving 1000mGy in utero, demonstrated a significant increase in 18FDG uptake and increased glycogen storage compared to sham group. However, female pups receiving 50mGy IR did not show a significant difference in 18FDG uptake or glycogen storage when compared to sham. Male pups did not exhibit increased 18FDG uptake, however at 50 and 300mGy IR there was decreased glycogen storage compared to sham. The reduced/oxidized glutathione redox ratio, a marker of oxidative stress, was significantly decreased in the female 300mGy and 1000mGy groups compared to sham but there was no change in males. We conclude that non‐lethal doses of radiation during late gestation can alter glucose uptake and storage as glycogen as well as oxidative status in female off‐spring. These data provide evidence that non‐lethal doses of radiation during the third trimester alter cardiac metabolism later in life and sex may have a role in fetal programming.Support or Funding InformationThis work was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and by our industry partner, Bruce Power.

Dietary Supplemented Curcumin Improves Meat Quality and Antioxidant Status of Intrauterine Growth Retardation Growing Pigs via Nrf2 Signal Pathway.

Simple SummaryMore than 15% of piglets and about 10% of newborn humans suffer from intrauterine growth retardation (IUGR), which refers to growth lag, developmental restriction and impaired organs in the fetus. IUGR exhibits programming consequences and exerts permanent negative effects on postnatal growth and health. Dietary supplemented curcumin, as the main natural polyphenol isolated from the natural antioxidant (turmeric), might show possible effects on antioxidant capacity, and the meat quality of IUGR pigs. Therefore, in our present study, 12 normal birth weight (NBW) and 24 IUGR neonatal female piglets were selected and fed control diets supplemented 0 (NBW), 0 (IUGR) and 200 (IUGR + Cur) mg/kg curcumin from 26 to 115 days of age (n = 12). The growth performance, meat quality, redox status and its related Nrf2 pathway were determined to test the hypothesis that curcumin may play beneficial roles against IUGR-induced oxidative stress. This study suggested that curcumin could serve as a potential natural antioxidant in nutrition interventions of IUGR offspring to enhance the redox status and improve the meat quality of leg muscles. These results attained from IUGR pig models can also provide some useful theoretical references for IUGR offspring in humans.Intrauterine growth retardation (IUGR) exhibits programming consequences and may induce oxidative stress in growing animals and humans. This study was conducted to investigate the hypothesis that dietary curcumin may protect growing pigs from IUGR-induced oxidative stress via the Nrf2 pathway. Twelve normal birth weight (NBW) and 24 IUGR female piglets were selected and fed control diets supplemented 0 (NBW), 0 (IUGR) and 200 (IUGR + Cur) mg/kg curcumin from 26 to 115 days of age (n = 12). Growth performance, meat quality, redox status and its related Nrf2 pathway were determined. Results showed that IUGR pigs exhibited decreased body weight on 0 d, 26 d and 56 d (p < 0.01) but had no difference on 115 d among NBW, IUGR and IUGR + Cur groups (p > 0.05). Compared with NBW and IUGR groups, a significant decrease in drip loss (24 h and 48 h) was observed in the IUGR + Cur group (p < 0.01). IUGR pigs had higher concentrations of malondialdehyde (MDA) (p < 0.01) and protein carbonyl (PC) (p = 0.03) and lower activities of glutathione peroxidase (p = 0.02), catalase (p < 0.01) and peroxidase (p = 0.02) in leg muscles than NBW pigs. Dietary-added 200 mg/kg curcumin decreased concentrations of MDA and PC and improved the activities of catalase, superoxide dismutase (SOD) and peroxidase as compared to the IUGR group (p < 0.05). Additionally, dietary curcumin enhanced protein (NQO1) and mRNA expression of genes (Nrf2, NQO1, gamma-glutamyltransferase 1 (GGT1), heme oxygenase-1 (HO-1), glutathione S-transferase (GST) and catalase (CAT)) as compared to the IUGR group (p < 0.05). These results suggest that dietary curcumin could serve as a potential additive to enhance redox status and improve meat quality of IUGR growing pigs via the Nrf2 signal pathway.

DJ-1 protects retinal pericytes against high glucose-induced oxidative stress through the Nrf2 signaling pathway

Oxidative stress has been associated with the etipathogenesis of Diabetic retinopathy (DR). Studies have shown that DJ-1 plays an important role in regulating the reactive oxygen species (ROS) production and resistance to oxidative stress-induced apoptosis. This study aimed to investigate whether DJ-1 upregulates oxidative stress and prevents damage to retinal capillary pericytes by increasing antioxidant capacity through the Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. Nrf2 is a redox-sensitive transcription factor that encode antioxidant enzymes and phase II metabolic enzymes, activation of Nrf2 functions is one of the critical defensive mechanisms against oxidative stress in many tissues. Our results showed after DJ-1 overexpression, apoptosis of rat retinal pericytes (RRPs) decreased, the ratio of B-cell lymphoma-2 (Bcl-2) to BCL2-Associated X Protein (BAX) increased, the production of ROS decreased, and the protein expression and activity of manganese superoxide dismutase (MnSOD, also called SOD2) and catalase (CAT) increased. DJ-1 overexpression activated Nrf2 expression, however, after Nrf2 silencing, apoptosis of RRPs increased, the ratio of Bcl-2 to BAX decreased, the production of ROS increased, the protein expression of MnSOD and CAT decreased, and the expression of heme oxygenase-1 (HO-1), NADP(H) quinone oxidoreductase (NQO1), glutamate-cysteine ligase catalytic subunit (GCLC) and modifier subunit (GCLM) decreased. These data suggest that enhancement of the Nrf2 pathway is a potential protective strategy for the treatment of DR. Therefore, DJ-1 may prevent high glucose-induced oxidative stress and RRPs apoptosis through the Nrf2 signaling pathway, thereby preventing the early onset and progression of DR.

Repetitively hypoxic preconditioning attenuates ischemia/reperfusion-induced liver dysfunction through upregulation of hypoxia-induced factor-1 alpha-dependent mitochondrial Bcl-xl in rat.

Repetitive hypoxic preconditioning (HP) enforces protective effects to subsequently severe hypoxic/ischemic stress. We hypothesized that HP may provide protection against ischemia/reperfusion (I/R) injury in rat livers via hypoxia-induced factor-1 alpha (HIF-1α)/reactive oxygen species (ROS)-dependent defensive mechanisms. Female Wistar rats were exposed to hypoxia (15 h/day) in a hypobaric hypoxic chamber (5500 m) for HP induction, whereas the others were kept in sea level. These rats were subjected to 45 min of hepatic ischemia by portal vein occlusion followed by 6 h of reperfusion. We evaluated HIF-1α in nuclear extracts, MnSOD, CuZnSOD, catalase, Bad/Bcl-xL/caspase 3/poly-(ADP-ribose)-polymerase (PARP), mitochondrial Bcl-xL, and cytosolic cytochrome C expression with Western blot and nitroblue tetrazolium/3-nitrotyrosine stain. Kupffer cell infiltration and terminal deoxynucleotidyl transferase-mediated nick-end labeling method apoptosis were determined by immunocytochemistry. The ROS value from liver surface and bile was detected by an ultrasensitive chemiluminescence-amplification method. Hepatic function was assessed with plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. HP increased nuclear translocation of HIF-1α and enhanced Bcl-xL, MnSOD, CuZnSOD, and catalase protein expression in a time-dependent manner. The response of HP enhanced hepatic HIF-1α, and Bcl-xL expression was abrogated by a HIF-1α inhibitor YC-1. Hepatic I/R increased ROS levels, myeloperoxidase activity, Kupffer cell infiltration, ALT and AST levels associated with the enhancement of cytosolic Bad translocation to mitochondria, release of cytochrome C to cytosol, and activation of caspase 3/PARP-mediated apoptosis. HP significantly ameliorated hepatic I/R-enhanced oxidative stress, apoptosis, and mitochondrial and hepatic dysfunction. In summary, HP enhances HIF-1α/ROS-dependent cascades to upregulate mitochondrial Bcl-xL protein expression and to confer protection against I/R injury in the livers.

Catalase immunoexpression in colorectal lesions.

IntroductionIt is generally accepted that the gastrointestinal tract, and especially the colon, is constantly exposed to reactive oxygen species (ROS) that may be responsible for the appearance of genetic mutations. To keep a steady-state control over ROS production-detoxification, organisms have evolved a defensive system. Nevertheless, many reports have described decreased level of antioxidant enzymes, especially catalase (CAT), in cancer tissues.AimIn this work we try to assess the immunohistochemical expression of CAT protein in colorectal adenoma and adenocarcinoma samples.Material and methodsThis study was performed on resected specimens obtained from 122 patients who had undergone surgical resection for colorectal cancer, and from 120 patients who had undergone colonoscopy. Paraffin- embedded, 4 µm-thick tissue sections were stained for rabbit polyclonal anti CAT antibody obtained from GeneTex (cat. no. GTX110704).ResultsIn adenoma strong immunoexpression was detected mainly in infiltrating mononuclear cells within lamina propria. High expression of CAT was significantly associated with grade of dysplasia (high grade vs. low grade, p = 0.037). In adenocarcinoma samples, the high level of CAT immunoexpression was significantly correlated with histological grade of tumour (G1 vs. G2 vs. G3, p = 0.001) and depth of invasion (T1 vs. T2 vs. T3 vs. T4, p = 0.003).ConclusionsDevelopment of colorectal cancer is associated with increased expression of CAT in the stage of adenoma and decreased expression in the stage of adenocarcinoma.

Chlorella sp. Protective Effect on Acetaminophen-Induced Liver Toxicity in ICR Mice.

Background:A Chlorella sp. (CLC) has a health supplement in health effects including an ability to treat cancer. The Chlorella sp. Ability to reduce acetaminophen-induced liver injury is still unknown. The hepatoprotective function of CLC was determined in an APAP-induced liver injury mouse model.Methods:Male ICR mice were randomly divided into normal control, APAP, APAP + Sm (silymarin) and APAP + CLC (0.2%, 0.5% and 1%) groups. The glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), Albumin, and BUN plasma activities were detected using blood biochemistry assay. The hepatic tissue GOT, GPT, superoxide dismutase (SOD) and catalase (CAT) activity were also detected. Lipid peroxidation, MDA, protein expression levels were examined.Results:The results showed that the 1% CLC supplementation group and Silymarin (Sm) could significantly alleviate increased serum GOT, GPT and BUN, and the decreased serum Albumin. At the same time, the increased hepatic tissue GOT and GPT activities were alleviated as well as MDA. Enhanced SOD and CAT protein expression levels were increased in APAP-induced liver injury. Lipofuscin and hepatic veins cups disappeared in the Sm and 1% CLC supplementation groups shown with H&E staining.Conclusions:Therefore, CLC probably could develop hepatoprotective products against chemical-induced liver damage.

Remarkable Protective Effects of Nrf2-Mediated Antioxidant Enzymes and Tissue Specificity in Different Skeletal Muscles of Daurian Ground Squirrels Over the Torpor-Arousal Cycle.

Hibernating mammals experience conditions of extreme oxidative stress, such as fasting, muscle disuse, and repeated hypoxic ischemia-reperfusion, during the torpor-arousal cycle. Despite this, they experience little oxidative injury and are thus an interesting model of anti-oxidative damage. Thus, in the current study, we explored the levels and underlying mechanism of oxidative stress and antioxidant capacity in three skeletal muscles [slow-twitch soleus (SOL), fast-twitch extensor digitorum longus (EDL), and mixed gastrocnemius (GAS)] of Daurian ground squirrels (Spermophilus dauricus) during hibernation. Results showed that hydrogen peroxide content in the EDL and GAS decreased significantly during pre-hibernation (PRE) and late torpor (LT) compared to levels in the summer active (SA) group. Furthermore, relative to SA levels, malondialdehyde content decreased significantly during interbout arousal (IBA) and early torpor (ET) in all three skeletal muscles and decreased in the EDL and GAS during LT. Compared with the SA group, glutathione peroxidase 1 (GPx1) and catalase (CAT) protein expression in the SOL and superoxide dismutase 1 (SOD1) and SOD2 expression in the GAS increased significantly during the entire hibernation season. Furthermore, SOD1 in the IBA group and CAT and GPx1 in the ET and LT groups increased significantly in the EDL. The activities of most tested antioxidant enzymes were higher in the IBA group than in the LT group, whereas CAT remained highly active throughout the hibernation season in all three muscles. Nrf2 and p-Nrf2 protein levels were significantly elevated in the SOL and EDL during hibernation, and increased during the PRE, IBA, and ET states in the GAS. Thus, activation of the Nrf2/Keap1 antioxidant pathway resulted in the elimination of excess reactive oxygen species (ROS). Specifically, ROS levels were maintained at physiological levels by the up-regulation of antioxidant enzyme expression in skeletal muscles under oxidative stress during hibernation, thus preventing oxidative injury over the torpor-arousal cycle. Different antioxidant patterns and oxidative stress levels were also observed among the different skeletal muscles of hibernating Daurian ground squirrels.

Calorie Restriction in Adulthood Reduces Hepatic Disorders Induced by Transient Postnatal Overfeeding in Mice

Impaired early nutrition influences the risk of developing metabolic disorders in later life. We observed that transient postnatal overfeeding (OF) in mice induces long-term hepatic alterations, characterized by microsteatosis, fibrosis associated with oxidative stress (OS), and stress-induced premature senescence (SIPS). In this study, we investigated whether such changes can be reversed by moderate calorie restriction (CR). C57BL/6 male mice pups were maintained during lactation in litters adjusted to nine pups in the normal feeding (NF) group and three pups in the transient postnatal OF group. At six months of age, adult mice from the NF and OF groups were randomly assigned to an ad libitum diet or CR (daily energy supply reduced by 20%) for one month. In each group, at the age of seven months, analysis of liver structure, liver markers of OS (superoxide anion, antioxidant defenses), and SIPS (lipofuscin, p53, p21, p16, pRb/Rb, Acp53, sirtuin-1) were performed. CR in the OF group reduced microsteatosis, decreased levels of superoxide anion, and increased protein expression of catalase and superoxide dismutase. Moreover, CR decreased lipofuscin staining, p21, p53, Acp53, and p16 but increased pRb/Rb and sirtuin-1 protein expression. CR did not affect the NF group. These results suggest that CR reduces hepatic disorders induced by OF.

Aerobic exercise modulates cardiac NAD(P)H oxidase and the NRF2/KEAP1 pathway in a mouse model of chronic fructose consumption.

The present study investigated the effects of exercise on the cardiac nuclear factor (erythroid-derived 2) factor 2 (NRF2)/Kelch-like ECH-associated protein 1 (KEAP1) pathway in an experimental model of chronic fructose consumption. Male C57BL/6 mice were assigned to Control, Fructose (20% fructose in drinking water), Exercise (treadmill exercise at moderate intensity), and Fructose + Exercise groups (n = 10). After 12 wk, the energy intake and body weight in the groups were similar. Maximum exercise testing, resting energy expenditure, resting oxygen consumption, and carbon dioxide production increased in the exercise groups (Exercise and Fructose + Exercise vs. Control and Fructose groups, P < 0.05). Chronic fructose intake induced circulating hypercholesterolemia, hypertriglyceridemia, and hyperleptinemia and increased white adipose tissue depots, with no changes in blood pressure. This metabolic environment increased circulating IL-6, IL-1β, IL-10, cardiac hypertrophy, and cardiac NF-κB-p65 and TNF-α expression, which were reduced by exercise (P < 0.05). Cardiac ANG II type 1 receptor and NAD(P)H oxidase 2 (NOX2) were increased by fructose intake and exercise decreased this response (P < 0.05). Exercise increased the cardiac expression of the NRF2-to-KEAP1 ratio and phase II antioxidants in fructose-fed mice (P < 0.05). NOX4, glutathione reductase, and catalase protein expression were similar between the groups. These findings suggest that exercise confers modulatory cardiac effects, improving antioxidant defenses through the NRF2/KEAP1 pathway and decreasing oxidative stress, representing a potential nonpharmacological approach to protect against fructose-induced cardiometabolic diseases.NEW & NOTEWORTHY This is the first study to evaluate the cardiac modulation of NAD(P)H oxidase (NOX), the NRF2/Kelch-like ECH-associated protein 1 pathway (KEAP), and the thioredoxin (TRX1) system through exercise in the presence of moderate fructose intake. We demonstrated a novel mechanism by which exercise improves cardiac antioxidant defenses in an experimental model of chronic fructose intake, which involves NRF2-to-KEAP1 ratio modulation, enhancing the local phase II antioxidants hemoxygenase-1, thioredoxin reductase (TXNRD1), and peroxiredoxin1B (PDRX1), and inhibiting cardiac NOX2 overexpression.