Glutathione Peroxidase mRNA Levels Research Articles

Antioxidant defenses at enzymatic and transcriptional levels in response to acute lead administration in Oxya chinensis

Lead (Pb) is known to be toxic to many organisms. Oxidative stress is a major mechanism of its toxicity. This research aims to investigate the effects of Pb on hydrogen peroxide (H2O2) and malonedialdehyde (MDA) contents, activities and mRNA levels of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx)) after Oxya chinensis were acutely treated with lead acetate for 24 h. The results showed that the LD50-24 h value of lead acetate to O. chinensis was 1541.89 (1431.19–1655.77) μg g−1 body H2O2 and MDA contents were elevated after Pb administration, which suggested that Pb induced the overproduction of ROS and caused oxidative stress. SOD activities were significantly inhibited 40.42% of the control by 280 μg μL−1 Pb. CAT activities were increased while GPx activities had no significant changes. Different types of antioxidant-related genes had various responses to Pb stress. The transcriptions of icCuZnSOD2 and ecCuZnSOD2 were significantly inhibited by different concentrations of Pb. MnSOD mRNA levels showed the concentration-dependent rise with the Pb concentrations increase. The expressions of ecCuZnSOD1, CAT1, and GPx were significantly up-regulated while the transcriptions of icCuZnSOD1 and CAT2 had no significant changes. Alteration of activities and mRNA expressions of antioxidant enzymes implied that Pb-induced antioxidant defenses were related to modifications at enzymatic and transcriptional levels. The profiles of antioxidant enzymes and H2O2 and MDA contents and relationships among the parameters indicated that the cooperation of multiple antioxidants rather than a single factor might be responsible for the antioxidant defenses against Pb stress.

Troglitazone inhibits the migration and invasion of PC-3 human prostate cancer cells by upregulating E-cadherin and glutathione peroxidase 3.

Troglitazone (TGZ) is a synthetic peroxisome proliferator-activated receptor γ (PPARγ) ligand that exhibits potential antitumor effects on a number of cancer subtypes, including prostate cancer. However, little is known about the effect of TGZ on metastasis in prostate cancer. The aim of the present study was to determine the inhibitory effect and mechanism underlying TGZ on cell growth, migration and invasion using the prostate cancer PC-3 cell line. Cellular migration and invasion were evaluated by performing a wound healing assay and Matrigel assay, respectively. The expression levels of mRNA and protein were determined by reverse transcription-quantitative polymerase chain reaction and western blotting. The results demonstrated that TGZ dose-dependently inhibited cell migration and invasion of PC-3 cells. The present study also revealed that TGZ increased the mRNA and protein levels of E-cadherin and glutathione peroxidase 3 (GPx3) in human prostate cancer PC-3 cells. In addition, GW9662, a PPARγ antagonist, attenuated the increased mRNA and protein levels of E-cadherin and GPx3, suggesting that the PPARγ-dependent signaling pathway was involved. Taken together, these results suggested that the anti-migration and anti-invasion effect of TGZ on PC-3 prostate cancer cells is, at least in part, mediated via upregulation of E-cadherin and GPx3. The present study also concluded that PPARγ may be used as a potential remedial target for the prevention and treatment of prostate cancer cell invasion and metastasis.

Impaired endocrine-metabolic homeostasis: underlying mechanism of its induction by unbalanced diet.

To characterize the intrinsic mechanism by which sucrose induces β-cell dysfunction. Normal rats received for 3 weeks a standard diet supplemented with 10% sucrose in the drinking water (high sucrose (HS)) with/out an antioxidant agent (R/S α-lipoic acid). We measured plasma glucose, insulin, triglyceride, leptin, and lipid peroxidation levels; homeostasis model assessment (HOMA)-insulin resistance (HOMA-IR) and HOMA for β-cell function (HOMA-β) indexes were also determined. Insulin secretion, β-cell apoptosis, intracellular insulin and leptin mediators, and oxidative stress (OS) markers were also measured in islets isolated from each experimental group. HS rats had increased plasma triglyceride, insulin, leptin, and lipid peroxidation (OS marker) levels associated with an insulin-resistant state. Their islets developed an initial compensatory increase in glucose-induced insulin secretion and mRNA and protein levels of β-cell apoptotic markers. They also showed a significant decrease in mRNA and protein levels of insulin and leptin signaling pathway mediators. Uncoupling protein 2 (UCP2), peroxisome proliferator-activated receptor (PPAR)-α and -δ mRNA and protein levels were increased whereas mRNA levels of Sirtuin-1 (Sirt-1), glutathione peroxidase, and catalase were significantly lower in these animals. Development of all these endocrine-metabolic abnormalities was prevented by co-administration of R/S α-lipoic acid together with sucrose. OS may be actively involved in the mechanism by which unbalanced/unhealthy diet induces β-cell dysfunction. Since metabolic-endocrine dysfunctions recorded in HS rats resembled those measured in human pre-diabetes, knowledge of its molecular mechanism could help to develop appropriate strategies to prevent the progression of this metabolic state toward type 2 diabetes (T2D).

Effect of nitrite exposure on the antioxidant enzymes and glutathione system in the liver of bighead carp, Aristichthys nobilis

Nitrite (NO2−) can cause oxidative stress in aquatic animal when it accumulates in the organism, resulting in different toxic effects on fish. In the present study, we investigated the effects of nitrite exposure on the antioxidant enzymes and glutathione system in the liver of Bighead carp (Aristichthys nobilis). Fish [Initial average weight: (180.05 ± 0.092) g] were exposed to 48.634 mg/L nitrite for 96 h, and a subsequent 96 h for the recovery test. Fish livers were collected to assay antioxidant enzymes activity, hepatic structure and expression of genes after 0 h, 6 h, 12 h, 24 h, 48 h, 72 h, 96 h of exposure and12 h, 24 h, 48 h, 72 h, 96 h of recovery. The results showed that the activity of glutathione peroxidase (GSH-Px), glutathione S-transferase (GST), and glutathione reductase (GR) increased significantly in the early stages of nitrite exposure. The study also showed that nitrite significantly up-regulated the mRNA levels of glutathione peroxidase (GSH-Px), glutathione S-transferase (GST), and glutathione reductase (GR) after 6, 48, and 72 h of exposure respectively. Nitrite also increased the formation of malondialdehyde (MDA), oxidized glutathione (GSSG), and the activity of catalase (CAT). Nitrite was observed to reduce the activity of superoxide dismutase (SOD) and the level of glutathione (GSH). In the recovery test, GSH and the GSSG recovered but did not return to pre-stress levels. The results suggested that the glutathione system played important roles in nitrite-induced oxidative stress in fish. The bighead carp responds to oxidative stress by enhancing the activity of GSH-Px, GST, GR and up-regulating the expression level of GSH-Px, GST, GR, a whilst simultaneously maintaining the dynamic balance of GSH/GSSG. CAT was also indispensable. They could reduce the degree of lipid peroxidation, and ultimately protect the body from oxidative damage.

Effect of Seleno-L-methionine on Oxidative Stress in the Pancreatic Islets of a Short-Term Induced Diabetic Mouse Model in Insufficient Selenium Status.

The protective effects of seleno-L-methionine (SeMet) on oxidative stress in pancreatic islets were investigated with a short-term nicotinamide (NA) and streptozotocin (STZ)-induced diabetic mouse model. ICR mice were intraperitoneally injected twice with 100 mg/kg STZ and 120 mg/kg NA at a 1-d interval and were then orally administered 158 µg Se/kg SeMet with free access to a selenium-deficient diet for 5 weeks. Administration of SeMet significantly improved the levels of glycated hemoglobin (HbA1c), non-fasting and oral glucose tolerance-tested (OGTT) blood glucose, plasma adiponectin and hepatic glycogen that deteriorated by NA/STZ treatment. However, supplementary SeMet did not restore non-fasting plasma insulin levels in NA/STZ treatment group and significantly suppressed OGTT plasma insulin levels in the control group. Although SeMet significantly suppressed 8-hydroxy-2'-deoxyguanosine density in pancreatic islets, SeMet did not restore insulin density. The hepatic and pancreatic mRNA levels of glutathione peroxidase 1 (GPX1) increased by NA/STZ treatment or SeMet administration. These results suggest that although a physiological level of SeMet improves glucose tolerance by exhibiting insulin-mimetic activity in a short-term induced diabetic mouse model under insufficient Se status, the suppression of pancreatic oxidative stress with the induction GPX1 by SeMet supplementation is unlikely to restore insulin storage and secretion.

Quercetrin from Toona sinensis leaves induces cell cycle arrest and apoptosis via enhancement of oxidative stress in human colorectal cancer SW620 cells.

Finding effective strategies against colorectal cancer (CRC) is still an emergent health problem. In the present study, we investigated the anticancer activity of quercetrin from Toona sinensis leaves (QTL) and explored the underlying mechanism in human CRC cell line SW620. The cells were treated with various concentrations of QTL and the cytotoxic effects of QTL were determined using the MTT assay. Apoptosis and cell cycle status were detected by flow cytometry. Reactive oxygen species (ROS) levels and mitochondrial membrane potential (∆Ψm) were assessed using DCF-DA and JC-1 fluorescence spectrophotometry, respectively. Western blot analysis was used to quantify the expression of apoptosis-related proteins. RT-PCR was applied to determine the mRNA levels of glutathione peroxidase (GPx) and catalase (CAT). QTL exhibited growth inhibitory effects and caused cell cycle arrest in the G2/M phase, which was accompanied by increased expression of p53 and p21 proteins. QTL promoted apoptosis which was consistent with the upregulated expression of Bax, cytochrome c, caspase-9, Apaf-1 and caspase-3. In addition, QTL induced the loss of mitochondrial membrane potential and triggered ROS generation, as revealed by the downregulated mRNA expression and enzymatic activity of GPx and CAT. Furthermore, both N-acetyl cysteine (NAC) and GSH attenuated the QTL-induced growth inhibition observed in SW620 cells along with the increase of ROS levels. These findings revealed that QTL inhibited the growth of CRC cells and facilitated apoptosis by enhancing oxidative stress. QTL may therefore have potential for use in CRC chemotherapy.

Does Metformin Protect Diabetic Patients from Oxidative Stress and Leukocyte-Endothelium Interactions?

Since metformin can exert beneficial vascular effects, we aimed at studying its effect on reactive oxygen species (ROS) production, antioxidant enzyme expression, levels of adhesion molecules, and leukocyte-endothelium interactions in the leukocytes from type 2 diabetic (T2D) patients. The study was carried out in 72 T2D patients (41 of whom were treated with metformin for at least 12 months at a dose of 1700 mg per day), and in 40 sex- and age-matched control subjects. Leukocytes from T2D patients exhibited enhanced levels of mitochondrial ROS and decreased mRNA levels of glutathione peroxidase 1 (gpx1) and sirtuin 3 (sirt3) with respect to controls, whereas metformin was shown to revert these effects. No changes were observed on total ROS production and the expression levels of superoxide dismutase 1 and catalase. Furthermore, increases in leukocyte-endothelial interactions and intercellular adhesion molecule-1 and P-selectin levels were found in T2D and were also restored in metformin-treated patients. Our findings raise the question of whether metformin could modulate the appearance of atherosclerosis in T2D patients and reduce vascular events by decreasing leukocyte oxidative stress through an increase in gpx1 and sirt3 expression, and undermining adhesion molecule levels and leukocyte-endothelium interactions. Antioxid. Redox Signal. 27, 1439-1445.

Glutathione peroxidase activity and expression levels are significantly increased in acute coronary syndromes

High levels of the antioxidant enzyme, glutathione peroxidase (GPx), have been associated with improved outcomes following acute coronary syndromes (ACS), suggesting a protective role. How GPx levels are altered with...

Low concentration of oleic acid exacerbates LPS-induced cell death and inflammation in human alveolar epithelial cells

ABSTRACTPurpose: The current study aimed to investigate in vitro effects of oleic acid on lipopolysaccharide (LPS)-induced acute lung injury in the human lung epithelial cells (A549). Materials and Methods: The cell viability was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tests. Selected gene expression levels were analyzed by Real-Time Quantitative-Polymerase Chain Reaction (RT-qPCR). Results: 24 hours of LPS (100 ng/mL) exposure decreased the cells’ viability by 44.6% compared to untreated control. Low concentration (2.5 nM) of oleic acid slightly suppressed the cell survival by 9.1% analyzed 24 hours after incubation. However, oleic acid pretreatment before LPS exposure significantly increased cell survival loss to 63.9%. LPS exposure decreased the expressions of catalase (CAT) and glutathione peroxidase (GPx) mRNA levels by 2.8 and 2.5 fold, respectively. Moreover, pretreatment of the cells with oleic acid strengthened LPS-decreased expressions of CAT and GPx genes by 3.5 and 6.7 fold, respectively. The mRNA expressions of superoxide dismutase (SOD), induced nitric oxide synthase (iNOS), interleukin-1β, IL-12, COX-2, caspase-3 and caspase-8 were increased by 2.4, 2.2, 2.2, 2.3, 3.0, 2.6, and 2.5 fold, respectively, by LPS, and oleic acid pretreatment significantly potentiated the effect of LPS. Conclusion: Oleic acid worsens LPS-induced cell death by potentiating oxidative stress and inflammation in A549 lung epithelial cells.

Bach1 siRNA attenuates bleomycin-induced pulmonary fibrosis by modulating oxidative stress in mice.

Oxidative stress plays an essential role in inflammation and fibrosis. Bach1 is an important transcriptional repressor that acts by modulating oxidative stress and represents a potential target in the treatment of pulmonary fibrosis (PF). In this study, we knocked down Bach1 using adenovirus-mediated small interfering RNA (siRNA) to determine whether the use of Bach1 siRNA is an effective therapeutic strategy in mice with bleomycin (BLM)-induced PF. Mouse lung fibroblasts (MLFs) were incubated with transforming growth factor (TGF)-β1 (5 ng/ml) and subsequently infected with recombined adenovirus-like Bach1 siRNA1 and Bach1 siRNA2, while an empty adenovirus vector was used as the negative control. The selected Bach1 siRNA with higher interference efficiency was used for the animal experiments. A mouse model of BLM-induced PF was established, and Bach1 siRNA (1×109 PFU) was administered to the mice via the tail vein. The results revealed that the Bach1 mRNA and protein levels were significantly downregulated by Bach1 siRNA. Furthermore, the MLFs infected with Bach1 siRNA exhibited increased mRNA and protein expression levels of heme oxygenase-1 and glutathione peroxidase 1, but decreased levels of TGF-β1 and interleukin-6 in the cell supernatants compared with the cells exposed to TGF-β1 alone. Bach1 knockdown by siRNA also enhanced the expression of antioxidant factors, but suppressed that of fibrosis-related cytokines in mice compared with the BLM group. Finally, the inflammatory infiltration of alveolar and interstitial cells and the destruction of lung structure were significantly attenuated in the mide administered Bach1 siRNA compared with those in the BLM group. On the whole, our findings demonstrate that Bach1 siRNA exerts protective effects against BLM-induced PF in mice. Our data may provide the basis for the development of novel targeted therapeutic strategies for PF.

Aging modifies daily variation of antioxidant enzymes and oxidative status in the hippocampus

BackgroundAging is a complex and multifactorial biological process that leads to the progressive deterioration of physiological systems, including the circadian system. In addition, oxidative stress has been associated with the aging of the normal brain and the development of late-onset neurodegenerative diseases. Even though, functional weakening of circadian rhythms and antioxidant function has been observed during aging, the mechanisms by which the circadian system signaling and oxidative stress are interrelated have not yet been elucidated. The objectives of this study were to evaluate the consequences of aging on the temporal organization of the antioxidant defense system and oxidative status as well as to analyze the endogenous clock activity, in the hippocampus of aged rats. MethodsYoung adults (3-month-old) or older (22-month-old) male Holtzman rats were maintained under constant darkness conditions, during 15days before the sacrifice. Levels of catalase (CAT) and glutathione peroxidase (GPx) mRNA and activity, reduced glutathione (GSH), lipoperoxidation (LPO) and BMAL1 protein were analyzed in hippocampus samples isolated every 4h during a 24-h period. Locomotor activity was recorded during 20days before the experiment. ResultsOur results show that aging modifies temporal patterns of CAT and GPx expression and activity in the hippocampus in a different way. On the one hand, it abolishes the oscillating CAT expression and specific enzymatic activity while, on the other, it increases the mesor of circadian GPx activity rhythm (p<0.01). Additionally, we observed increased GSH (p<0.05) and reduced LPO (p<0.01) levels in the hippocampus of aged rats. Moreover, the nocturnal locomotor activity was reduced in the older animals in comparison to the young adult rats (p<0.01). Interestingly, the 22month-old animals became arrhythmic and showed a marked fragmentation as well as a significant decline in daily locomotor activity when they were maintained under constant darkness conditions (p<0.05). Aging also abolished circadian rhythms of the core clock BMAL1 protein. ConclusionThe loss of temporal organization of the antioxidant enzymes activity, the oxidative status and the cellular clock machinery could result in a temporally altered antioxidant defense system in the aging brain. Learning about how aging affects the circadian system and the expression of genes involved in the antioxidant defense system could contribute to the design of new strategies to improve the quality of life of older people and also to promote a healthy aging.

Selenium-enriched Saccharomyces cerevisiae improves growth, antioxidant status and selenoprotein gene expression in Arbor Acres broilers.

One hundred and fifty 7-day-old Arbor Acres broilers were randomly assigned into five groups: group 1 served as a control that was fed a basal diet without selenium (Se) supplementation; groups 2, 3 and 4 were fed the basal diet supplemented with 0.15, 0.5 and 1.5mg Se as Se-enriched Saccharomyces cerevisiae (SSC) per kg of diet; and group 5 was fed the basal diet supplemented with 0.15mg per kg of Se as sodium selenite (SS). Growth performance, glutathione peroxidase (GPX ) and superoxide dismutase (SOD) activities, total antioxidant capacity (T-AOC), and malondialdehyde (MDA) content in plasma and liver, and cellular glutathione peroxidase (GPX -1) and phospholipid hydroperoxide glutathione peroxidase (GPX -4) mRNA levels in liver were determined. Compared with group 1, groups 2-4 exhibited higher body weights (p<0.05), lower feed/gain ratios, and higher GPX activities in plasma (p<0.05) and GPX and SOD activities and GPX -1 and GPX -4 mRNA levels in liver (p<0.05). Compared with group 5, group 2 exhibited higher GPX activity in plasma on day 21 (p<0.05). Compared with group 2 and 5, group 3 exhibited lower MDA content in plasma on day 7 (p<0.05), higher GPX activity in plasma, SOD activity and GPX -1 mRNA levels in liver on day 14 and 21 (p<0.05), and higher GPX -4 mRNA levels on day 14 (p<0.05). Compared with group 4, group 3 exhibited lower MDA contents in plasma on day 14 (p<0.05) and in liver on day 21 (p<0.05), higher T-AOC in plasma and higher GPX -1 mRNA levels on day 14 and 21 (p<0.05), and higher SOD activity in plasma and higher SOD and GPX activities in liver on day 21 (p<0.05). Thus, SSC improves growth and antioxidant status of broilers; the short-term bioavailability of SS was faster than that of SSC, but the long-term bioavailability of SSC was greater than SS.

Wheat bran feruloyl oligosaccharides ameliorate AAPH-induced oxidative stress in HepG2 cells via Nrf2 signalling

Protective effects of wheat bran feruloyl oligosaccharides (FOs) against 2, 2′-Azobis (2-methylpropionamidine) dihydrochloride (AAPH)-induced oxidative stress in HepG2 cells were investigated. The cytoprotective effects of FOs against oxidative challenge were determined by cell viability, intracellular reactive oxygen species (ROS) generation, and lactate dehydrogenase (LDH) leakage. The antioxidant activities of FOs were investigated by determining the activities and mRNA expression levels of phase II detoxifying/antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). FOs concentrations had a positive correlation with cell viability and a negative correlation with the LDH activity. FOs treatment increased the activities and mRNA levels of SOD, CAT, and GPx. Moreover, the nuclear factor E2 related factor (Nrf2) protein expression in the FOs group positively correlated with the SOD, CAT, and GPx protein levels. Thus the results demonstrated that FOs treatment could ameliorate AAPH-induced oxidative stress in HepG2 cells via Nrf2 signalling.

Reproductive toxicity of inorganic mercury exposure in adult zebrafish: Histological damage, oxidative stress, and alterations of sex hormone and gene expression in the hypothalamic-pituitary-gonadal axis

Mercury (Hg) is a prominent environmental contaminant that causes a variety of adverse effects on aquatic organisms. However, the mechanisms underlying inorganic Hg-induced reproductive impairment in fish remains largely unknown. In this study, adult zebrafish were exposed to 0 (control), 15 and 30μg Hg/l (added as mercuric chloride, HgCl2) for 30days, and the effects on histological structure, antioxidant status and sex hormone levels in the ovary and testis, as well as the mRNA expression of genes involved in the hypothalamic-pituitary-gonadal (HPG) axis were analyzed. Exposure to Hg caused pathological lesions in zebrafish gonads, and changed the activities and mRNA levels of antioxidant enzymes (catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx)) as well as the content of glutathione (GSH) and malondialdehyde (MDA). In females, although ovarian 17β-estradiol (E2) content remained relatively stable, significant down-regulation of lhβ, gnrh2, gnrh3, lhr and erα were observed. In males, testosterone (T) levels in the testis significantly decreased after Hg exposure, accompanied by down-regulated expression of gnrh2, gnrh3, fshβ and lhβ in the brain as well as fshr, lhr, ar, cyp17 and cyp11b in the testis. Thus, our study indicated that waterborne inorganic Hg exposure caused histological damage and oxidative stress in the gonads of zebrafish, and altered sex hormone levels by disrupting the transcription of related HPG-axis genes, which could subsequently impair the reproduction of fish. Different response of the antioxidant defense system, sex hormone and HPG-axis genes between females and males exposed to inorganic Hg indicated the gender-specific regulatory effect by Hg. To our knowledge, this is the first time to explore the effects and mechanisms of inorganic Hg exposure on reproduction at the histological, enzymatic and molecular levels, which will greatly extend our understanding on the mechanisms underlying of reproductive toxicity of inorganic Hg in fish.

The alteration of mRNA expression of SOD and GPX genes, and proteins in tomato (Lycopersicon esculentum Mill) under stress of NaCl and/or ZnO nanoparticles.

Five cultivars of tomato having different levels of salt stress tolerance were exposed to different treatments of NaCl (0, 3 and 6 g L−1) and ZnO-NPs (0, 15 and 30 mg L−1). Treatments with NaCl at both 3 and 6 g L−1 suppressed the mRNA levels of superoxide dismutase (SOD) and glutathione peroxidase (GPX) genes in all cultivars while plants treated with ZnO-NPs in the presence of NaCl, showed increments in the mRNA expression levels. This indicated that ZnO-NPs had a positive response on plant metabolism under salt stress. Superior expression levels of mRNA were observed in the salt tolerant cultivars, Sandpoint and Edkawy while the lowest level was detected in the salt sensitive cultivar, Anna Aasa. SDS–PAGE showed clear differences in patterns of protein expression among the cultivars. A negative protein marker for salt sensitivity and ZnO-NPs was detected in cv. Anna Aasa at a molecular weight of 19.162 kDa, while the tolerant cultivar Edkawy had two positive markers at molecular weights of 74.991 and 79.735 kDa.

Effect of static magnetic fields and phloretin on antioxidant defense system of human fibroblasts.

The available evidence from in vitro and in vivo studies is deemed not sufficient to draw conclusions about the potential health effects of static magnetic field (SMF) exposure. Therefore, the aim of the present study was to determine the influence of static magnetic fields and phloretin on the redox homeostasis of human dermal fibroblasts. Control fibroblasts and fibroblasts treated with phloretin were subjected to the influence of static magnetic fields. Three chambers with static magnetic fields of different intensities (0.4, 0.55, and 0.7 T) were used in the study. Quantification of superoxide dismutase 1 (SOD1), superoxide dismutase 2 (SOD2), glutathione peroxidase 1 (GPX1), microsomal glutathione S-transferase 1 (MGST1), glutathione reductase (GSR), and catalase (CAT) messenger RNAs (mRNAs) was performed by means of real-time reverse transcription PCR (QRT-PCR) technique. Superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities were measured using a commercially available kit. No significant differences were found in SOD1, SOD2, GPX1, MGST1, GSR, and CAT mRNA levels among the studied groups in comparison to the control culture without phloretin and without the magnet. There were also no changes in SOD, GPx, and CAT activities. In conclusion, our study indicated that static magnetic fields generated by permanent magnets do not exert a negative influence on the oxidative status of human dermal fibroblasts. Based on these studies, it may also be concluded that phloretin does not increase its antioxidant properties under the influence of static magnetic fields. However, SMF-induced modifications at the cellular and molecular level require further clarification.

Selenium Requirements in Rats, Mice, Lambs, Chicks and Turkeys Based on Selenoprotein Enzyme Activity and Transcript Level

Over the past several years, my lab has conducted a series of studies to evaluate selenium (Se) status and requirements in rats, mice and lambs, all using virtually the same diets. These studies progressed from using glutathione peroxidase (GPX) activity as the primary biomarker, to use of GPX protein and GPX mRNA levels as biomarkers, and recently we expanded to include additional selenoenzyme activities as well as transcript levels for the full selenoproteome. Literature reports of Se requirements of turkeys have consistently indicated that turkeys have a markedly higher Se requirement than mammals (NRC: 0.2 μg Se/g). Thus we evaluated the Se requirements of turkey poults, and in parallel, of chicks. The objective here is to compare resulting requirements and to identify clues to better understand the underlying differences in Se requirements and in Se‐deficiency target tissues. For all studies, animals were fed a basal torula yeast diet (0.005–0.007 μg Se/g) with graded levels of Se supplemented as selenite for 4 weeks (lambs 8 wk). Se response curves result in well‐defined Se‐adequate plateaus for all biomarkers except RBC GPX1 activity. Based on plasma GPX3, liver GPX1, and RBC GPX1 activities, the mammalian minimal dietary Se requirement is uniformly 0.1 μg Se/g, whereas the turkey requirement is clearly 3‐times higher at 0.3 μg Se/g; the chick minimum Se requirement is 0.15 μg Se/g based on plasma GPX3 and GPX1 activities. Liver GPX4 activity is only modestly affected by Se deficiency in rats, but falls to ~10% of plateau levels in mice, chicks and poults. In contrast to selenoenzyme activity biomarkers, requirements based on liver GPX1 mRNA are uniformly 0.04–0.11 μg Se/g for rodents and avians, with GPX1 mRNA in Se deficiency falling more dramatically in rodents vs. avians. GPX4 mRNA is little affected by Se deficiency in rodents but falls to 30% in avians. Other unique species differences include high expression of GPX3 mRNA in avian liver; plasma GPX3 activity in Se deficiency falls to 1–3% of plateau levels in rats, chicks, poults and lambs and but only to 35% in mice. Sigmoidal Se response curves are observed for liver GPX1 activity in rats, chicks, turkeys and lambs, and for plasma GPX3 activity in mice, indicating that Se is preferentially directed to other selenoenzymes and/or tissues under Se‐deficient conditions. No mRNA response curves are markedly sigmoidal. Notably, there are no selenoprotein mRNAs that can be used as biomarkers for supernutritional Se status. These studies demonstrate that the minimum dietary Se requirement of young mammals falls over a narrow range, while the requirement of chicks is slightly higher, and turkey requirements are 3‐times that of mammals. Differences in these biomarker Se response curves may help to understand Se metabolism and targeting of tissues in Se deficiency, and thus help to better characterize Se requirements.Support or Funding InformationUSDA Hatch 233618 and 1004389, Northeast Agricultural Univ NECT‐1207‐02 and 1252‐ NCET‐009, and UW Selenium Nutrition Research Fund

Differential effects of docoosahexaenoic and arachidonic acid on fatty acid composition and myosin heavy chain-related genes of slow- and fast-twitch skeletal muscle tissues.

Myosin heavy chain (MHC) mediates the metabolic and contractile responses of skeletal muscles. MHC displays different isoforms, each of which has different characteristics. To better understand the effect of polyunsaturated fatty acids in skeletal muscles, rats were fed with control-, docosahexaenoic acid (DHA)-, and arachidonic acid (ARA)-oil, and the effects on plasma and muscular fatty acid profile, oxidative stress, mRNA levels of myosin heavy chain isoforms MHC1 of slow-twitch muscle (SO) and MHC2A, MHC2X, and MHCB isoforms of extensor digitorum longus (EDL) of fast-twitch muscle were evaluated. Concomitantly, mRNA levels of anti-oxidative enzymes, such as, catalase, glutathione peroxidase (GPx) and superoxide dismutase (SOD were determined. The expressions of MHC1, MHC2A, MHC2X, and MHC2B were lower in the SO of the DHA-fed rats. In the EDL muscles of DHA-fed rats, the expressions of MHC1 and MHC2A increased; however, the expressions of MHC2X increased and that of the MHC2 were not altered. Oxidative stress, as indicated by the levels of LPO, was significantly higher in the plasma of the ARA-fed rats, when compared with that of the DHA-fed rats. The LPO levels were higher both in the SO and EDL muscles of ARA-fed rats. Compared with ARA oil intake, DHA oil showed higher mRNA levels of GPx and SOD. Catalase expression was higher only in the EDL but not in the SO-type muscles. Our studies finally indicate that DHA and ARA differentially affect the regulation of contractile and metabolic properties of slow- and fast-twitch skeletal muscles.

The Protective Effects of Different Sources of Maternal Selenium on Oxidative Stressed Chick Embryo Liver.

The experiment was conducted to investigate the protective effects of different sources of maternal selenium (Se) on oxidative stressed chick embryo. A total of 270 Lingnan Yellow broiler breeders were randomly allocated into three treatments with five replicates for 18 birds each. Breeders were fed with basal diet (BD) including 0.04mg/kg Se or BD supplemented with sodium selenite (SS) or selenomethionine (SM) at a level of 0.15mg Se/kg. The rearing experiment lasted for 8weeks after an 8-week pre-test. Twenty eggs were collected from each replicate during the last 10-day, then incubated in a commercial incubator. On embryonic 17th, fertile eggs were transferred into 39.5°C temperature stimulation for 6h. Afterward, five eggs were randomly selected from each replicate for collecting chick embryo sample. The results showed that Se supplementation in the diet of breeders resulted in lower reactive oxygen species (ROS), heat shock protein 70 (HSP70), malondialdehyde (MDA), carbonyl and 8-hydroxydeoxyguanosine (8-OHdG) concentrations and higher glutathione peroxidase (GPx), total superoxide dismutase (T-SOD), and catalase (CAT) activities in heat stress treated chick embryo (P < 0.05), and ROS, MDA, carbonyl, 8-OHdG concentrations in SM treatment were lower than those in SS treatment (P < 0.05). Se supplementation elevated cellular glutathione peroxidase (GPx1) mRNA level and activity, cytoplasmic thioredoxin reductase (TrxR1) activity and selenoprotein P (SelP) mRNA and protein level (P < 0.05), and maternal SM showed a higher value than maternal SS in upregulating GPx1, TrxR1, and SelP mRNA levels as well as GPx1 and TrxR1 activities or SelP protein level (P < 0.05). This study indicated that maternal Se can enhance antioxidative capacity and reduce ROS concentration and oxidative damage by upregulating the expression of antioxidative selenoprotein, and maternal SM is superior to SS in heat stress treated chick embryo.

Resveratrol ameliorates cisplatin-induced oxidative injury in New Zealand rabbits.

This study investigated the preventive role of resveratrol in cisplatin-induced nephrotoxicity. The study used groups of New Zealand rabbits that were treated as follows: group C (cisplatin treated), group R (resveratrol treated), group R+C (resveratrol + cisplatin treatment), and group E (control group). Kidney levels of glutathione were significantly lower in group C than in groups E and R, whereas glutathione levels in group R+C were found to be similar to the control values. Malondialdehyde levels in group C were significantly higher than in groups E and R. However, malondialdehyde levels in group R+C were similar to group E. Kidney levels of nitric oxide were significantly higher in the cisplatin group than in the control, whereas nitric oxide levels were at basal values in group R+C. Cisplatin treatment significantly reduced kidney levels of glutathione peroxidase, superoxide dismutase, and catalase activity compared with those of group E, whereas resveratrol treatment significantly increased levels of glutathione peroxidase, superoxide dismutase, and catalase activity in group R+C. However, cisplatin injection did not affect mRNA levels of glutathione peroxidase, superoxide dismutase, or catalase enzymes. Histopathological and immunohistochemical analyses indicated that cisplatin caused kidney damage, which was mostly prevented by resveratrol treatment. In conclusion, resveratrol ameliorates cisplatin-induced oxidative injury in the kidney of rabbit.