Zn Superoxide Dismutase Activity Research Articles

Effects of copper exposure and recovery in juvenile yellowtail kingfish (Seriola lalandi): Histological, physiological and molecular responses

This study investigated the physiological responses to copper toxicity in liver and gill of juvenile yellowtail kingfish by exposing to 0 (control), 0.0672, 0.12, 0.214, 0.384, 0.672, 1.20, or 2.14 mg/L copper sulfate for 7 days and then recovered for 14 days. The histopathology, enzyme activities and differential gene expression were detected. The results indicate the safe concentration value of copper for juvenile yellowtail kingfish is 0.083 mg/L. Copper exposure caused structural damage to gill and liver, and could be disappeared or restored after the recovery period. Copper exposure enhanced the Cu,Zn superoxide dismutase (Cu/Zn-SOD) and glutathione peroxidase (GSH-Px) activities and the malondialdehyde (MDA) level in liver. However, with increasing copper concentrations, liver aspartate transaminase (AST) and gill Na+/K+-ATPase activities were at first enhanced and then inhibited. Serum lysozyme (LZM) and Cu/Zn-SOD activities were enhanced at low copper concentrations but inhibited at high concentrations, and the activities of alanine transaminase (ALT) and AST significantly increased at greater copper concentrations. After the recovery period, only liver Cu/Zn-SOD activity returned to control level. In contrast, liver GSH-Px activity and MDA levels and gill Na+/K+-ATPase activity, serum LZM and AST activities remained significantly higher than control, but liver AST activity, serum ALT, and Cu/Zn-SOD activities were significantly lower than control. We constructed the gene regulatory networks of molecular pathways in liver and gill in response to copper exposure. The DEGs were enriched mainly in the pathway of lipid metabolism in liver and pathway of oxidative phosphorylation in gill, indicating these respective pathways are involved in the response to copper stress in this species. The present results elucidate some histological, physiological, and molecular mechanisms underlying copper-exposure stresses in yellowtail kingfish, which could help guide the safe utilization of copper sulfate in disease control of farmed individuals.

Herbicide Roundup shows toxic effects in nontarget organism Drosophila.

Glyphosate-based herbicide Roundup, as the most employed herbicide used for multiple purposes in agriculture, adversely affects nontarget organisms. We tested the effects of Roundup applied at larval and adult stages. Roundup caused developmental delay and increased larvae mortality. Roundup treatment reduced hemolymph glucose and glycogen levels in adult flies of both sexes at the highest concentration tested. Sex-dependent diverse effects were found in catalase and Cu,Zn superoxide dismutase (Cu,Zn-SOD) activities. Decreased aconitase activity, contents of thiols, and lipid peroxides were found after larval Roundup exposure. Furthermore, chronic exposure to adult flies decreased appetite, body weight, and shortened lifespan. Thus, our results suggest that high concentrations of Roundup are deleterious to both larvae and adults, resulting in a shift of the metabolism and antioxidant defense system in Drosophila melanogaster.

CeO2 nanoparticles modulate Cu–Zn superoxide dismutase and lipoxygenase-IV isozyme activities to alleviate membrane oxidative damage to improve rapeseed salt tolerance

Rapeseed is an important cash crop. However, its yield and quality are significantly affected by salinity stress. Nanoceria helped to improve rapeseed salt tolerance via modulating Cu–Zn SOD and LOX-IV isozyme activities.

Indicator Characterizing Carbonyl-Dependent Modification of Erythrocytic Superoxydismutase as a Biochemical Marker of Oxidative Stress in Coronary Heart Disease

Aim To study the oxidative modification of red blood cell Cu,Zn superoxide dismutase (SOD) in patients with ischemic heart disease (IHD) in vivo and in vitro to substantiate the use of a new oxidative stress marker.Material and methods Red blood cell Cu,Zn SOD was measured by depression of nitrotetrazolium blue reduction by the superoxide anion generated in xanthine oxidase xanthine oxidation. Red blood cell Cu,Zn SOD was measured immunochemically. The biochemical study was performed in the control group (patients with low extremity fracture without known history of cardiovascular diseases and hyperlipidemia) and in groups of patients with acute myocardial infarction, stable angina, and decompensated heart failure. For evaluation of oxidative stress intensity in IHD patients, an empirical SOD oxidative modification coefficient (OMCSOD) was proposed, which is a Cu,Zn SOD activity / Cu,Zn SOD content ratio.Results The red blood cell Cu,Zn SOD activity was significantly decreased in all IHD groups compared to the control group. Furthermore, OMCSOD was also considerably decreased in IHD patients, which warrants the use of this biochemical index as an oxidative stress marker.Conclusion It was shown that the Cu,Zn SOD modification was induced by interaction of the enzyme molecules with a natural dicarbonyl, malonic dialdehyde, and OMCSOD can be used for evaluation of oxidative stress intensity in IHD patients.

Is D-Galactose a Useful Agent for Accelerated Aging Model of Gastrocnemius and Soleus Muscle of Sprague-Dawley Rats?

Elderly population and age-related diseases are on the rise. On the contrary, aging studies are technically hard to conduct, because they require elderly animals, the maintenance of which requires ample effort and is expensive. To tackle this problem, D-galactose is used to hasten the aging process in various tissues in rodent models and it has been shown to successfully mimic the oxidative alterations that take place in the natural aging process in various tissues both by our group and others. In the present study, the validity of D-galactose aging model in skeletal muscles was tested both on predominantly slow-twitch (soleus) and rather fast-twitch (gastrocnemius) muscle in male Sprague-Dawley rats and the results are compared with young littermate controls and naturally aged rats. Redox-related modifications in soleus and gastrocnemius were assessed by measurement of protein carbonyl groups, advanced oxidation protein products, lipid hydroperoxides, total thiol, and Cu, Zn-superoxide dismutase activities. In the present study, we provide biochemical evidence demonstrating that D-galactose-induced mimetic aging does result in oxidative stress-related redox alterations that are comparable with the alterations that occur in natural aging in soleus. On the contrary, in the D-galactose-induced mimetic aging of gastrocnemius, even though the oxidative stress markers were significantly increased, the endpoint redox homeostasis markers were not statistically comparable with the redox status of naturally aged group.

Tat-HSP70 protects neurons from oxidative damage in the NSC34 cells and ischemic damage in the ventral horn of rabbit spinal cord

Heat shock protein 70 (HSP70) is an ATP-dependent molecular chaperone, and it has been shown that its levels increase after exposure to various types of stress, including ischemia. In the present study, we investigated the effects of HSP70 against H2O2-induced neuronal stress in NSC34 cells and against spinal cord ischemia in rabbits. Tat-HSP70 proteins facilitated the intracellular delivery of HSP70 into the NSC34 cells and enabled them to cross the blood-brain barrier in the rabbit spinal cord. Tat-HSP70 was effectively transduced into NSC34 cells in a concentration- and time-dependent manner, while control-HSP70 protein could not be delivered intracellularly at any concentration or time after treatment. Treatment with Tat-HSP70 reduced the generation of reactive oxygen species and cell death induced by H2O2, while the control-HSP70 did not show any significant effect on the NSC34 cells exposed to H2O2. In rabbit spinal cord, the administration of Tat-HSP70 showed significant amelioration of neurological defects and neuronal death in the ventral horn of spinal cord. In addition, Tat-HSP70 treatment significantly reduced lipid peroxidation and increased Cu, Zn-superoxide dismutase activities in the spinal cord, but glutathione peroxidase and Mn-superoxide dismutase activities remained unchanged. These results suggest that Tat-HSP70, not control-HSP70, decreases cell damage by reducing oxidative stress in NSC34 cells and rabbit spinal cord, and it can be employed for the reduction of neuronal damage caused after spinal cord ischemia.

Tolerance Mechanisms to Copper and Zinc Excess in Rhizophora mucronata Lam. Seedlings Involve Cell Wall Sequestration and Limited Translocation.

Rhizophora mucronata is a common mangrove growing in habitats subjected to heavy metal (HM) contamination. Understanding their physiological responses to copper (Cu) and zinc (Zn) excess and underlying tolerance mechanisms is crucial to assess impacts of metal pollution on mangrove community. Seedlings were treated with Cu or Zn (0, 50 or 100mg per plant) by means of a single addition. At day 3 and 7, Cu and Zn accumulation, photosynthetic efficiency, superoxide dismutase and peroxidase activity, non-protein thiols, reactive oxygen species and lipid peroxidation in roots and leaves were measured. R. mucronata restricted Cu and Zn translocation, thus accumulated HM mainly in roots while kept the leaves unaffected. However, high root HM did not induce oxidative stress nor anti-oxidative defense as HM were largely deposited in cell wall. We concluded that HM tolerance strategies of R. mucronata seedlings are exclusion and restriction of translocation to the vital photosynthetic tissue.

Superoxide dismutase: a review and a modified protocol for activities measurements in rat livers

Superoxide dismutase (SOD) enzymes are considered the first line of Defence against reactive oxygen species. Among the intracellular isoforms of SOD, Cu,ZnSOD is widely distributed, and the MnSOD is localised in the mitochondria. The SOD activities have been measured indirectly by inhibiting oxidation reactions. Most techniques assessing the hepatic SOD activity are adaptations of classical methods and differ significantly from each other. This work assessed the hepatic Cu,ZnSOD activity in the supernatants of two different centrifugations, using two isotonic medium and the pyrogallol method. In most studies conducted in rat liver, only the Cu,Zn or total SOD activities were assessed and sometimes the Cu,ZnSOD activity was calculated based on the inhibition by cyanide. But, as demonstrated here, this inhibition is not complete. Besides, the novelty of this work is that we presented a method for the evaluating the Cu,ZnSOD and MnSOD activities separately and from the same liver.

Effect of zinc concentration and source on performance, tissue mineral status, activity of superoxide dismutase enzyme and lipid peroxidation of meat in broiler chickens

The present experiment was conducted to investigate the effect of feeding different concentrations and the source of zinc (Zn) on the performance, tissue mineral status, superoxide dismutase (SOD) enzyme activity and meat quality in 0–4-week-old broiler chicks. Dietary treatments included the corn–soybean meal-based diet (control) and the basal diet supplemented with Zn at 20, 50 or 80 mg/kg, added as ZnSO4, Zn-methionine or Zn-enriched yeast. The results showed that birds fed Zn-supplemented diets had higher average weight gain and average feed intake than did birds fed the control diet (P < 0.01). At the end of the experiment, the Zn deposition in pancreas, liver and tibia increased (P < 0.01), regardless of the source, in response to increasing dietary Zn concentrations, whereas plasma Zn status was significantly increased by the highest Zn supplementation level. The main effect of Zn supplementation level was significant for the activities of Cu and/or Zn SOD in the liver and pancreas (P < 0.01). As broiler given 50 mg Zn had higher tissue SOD activity than did broilers fed the other treatment diets. Furthermore, Zn supplementation at up to 50 mg/kg significantly increased (P < 0.01) Zn accumulation and SOD activity and decreased lipid peroxidation in muscles around the femur bone. Results from the present study demonstrated that supplementation with 50 mg Zn may be sufficient for normal broiler growth to 28 days of age and the dietary inclusion of organic Zn could be utilised more effectively than that of inorganic sources.

Crucial Roles of Systemic and Tissue Lipid Peroxidation Levels and Anti-Oxidant Defences Following Contrast Agent Application.

BackgroundOne of the most important side effects of contrast pharmaceutical agents, which are used very common in routine radiology practice, is contrast induced nephropathy. Even ischemia, oxidative stress and osmolality related cytotoxic effects are considered, the molecular mechanisms underlying this pathology have not been identified completely yet.ObjectivesThe aim of the current study was to reveal the role of oxidative stress and antioxidant enzymatic defence mechanisms in the aetiopathogenesis of contrast-induced nephropathy. We also studied possible alleviating effects of N-acetylcysteine (NAC), a potent antioxidant, to obtain extra information regarding the molecular mechanisms underlying this pathology.Materials and MethodsThis is an clinical-experimental study, This study was conducted of Istanbul/Turkey between September 15, 2012 and April 15, 2013. Three groups of male rats were randomly set up as a control group (C), a 100 mg/kg intraperitoneal NAC + 7 mL/kg contrast agent group (N + CIN) and a 7 mL/kg intraperitoneal contrast agent group (CIN). They were placed in individual metabolic cages 48 hours after agent administration to obtain 24-hour urine samples. Renal function tests (albumin, urea, creatinine, total protein) were conducted, oxidative stress parameters (Cu, Zn superoxide dismutase activity - Cu, Zn-SOD; advanced oxidation protein products - AOPP; protein carbonyls - PCO; total thiol groups - T-SH; and lipid hydroperoxides -LHP) were measured and tissues were analysed histopathologically.ResultsCompared with the control group, groups CIN and N + CIN had significantly higher urea and LHP levels (P < 0.05 and P < 0.001, respectively) and significantly lower Cu, Zn-SOD activity and creatinine clearance (P < 0.05). There was no statistically significant difference between the groups in PCO or AOPP levels despite differences in descriptive statistics.ConclusionsContrast-agent-induced nephropathic changes are more closely related to the magnitude of lipid peroxidation than protein oxidation.

Effects of Dendropanax morbifera Léveille extracts on cadmium and mercury secretion as well as oxidative capacity: A randomized, double-blind, placebo-controlled trial.

In this randomized, double-blind, placebo controlled clinical trial, the effects of Dendropanax morbifera (D. morbifera) Léveille on heavy metal (cadmium and mercury) excretion as well as on lipid peroxidation and Cu, Zn-superoxide dismutase (SOD1) activity were investigated. For this study, tablets containing placebo or 300 mg of the leaf extract from D. morbifera Léveille were used. A total of 60 eligible healthy subjects were enrolled in this randomized, double-blind, placebo-controlled study. The differences in cadmium, mercury, and malondialdehyde (MDA) levels and SOD1 activity were measured in the serum 60 days after treatment with placebo or D. morbifera Léveille extracts. No significant differences between baseline characteristics and biochemical values were identified in subjects in the placebo and D. morbifera Léveille groups. Serum levels of cadmium, mercury and MDA decreased following consumption of D. morbifera Léveille extracts; however, no significant differences were identified. In addition, female, but not male, subjects who consumed D. morbifera Léveille extracts showed a significant increase in SOD1 activity. This result suggests that chronic consumption of D. morbifera Léveille extract can help to facilitate excretion of cadmium and mercury from serum and increase the antioxidant capacity in humans.

Relation between Endothelial Nitric Oxide Synthase Genotypes and Oxidative Stress Markers in Larynx Cancer.

Nitric oxide synthase (eNOS/NOS3) is responsible for the endothelial synthesis of nitric oxide (NO•). G894T polymorphism leads to the amino acid substitution from Glu298Asp that causes lower NOS3 activity and basal NO• production in NOS3 894T (298Asp) allele carriers compared with the GG homozygotes. NO• acts as an antioxidant protecting against Fenton's reaction which generates highly reactive hydroxyl radicals. Allelic variation of NOS3 may influence an individual's risk of laryngeal cancer (LC). In the current study we have examined the possible relationship between NOS3 G894T genotypes and various systemic oxidative damage markers such as protein carbonyl, advanced oxidation protein products, Cu, Zn-superoxide dismutase, thiol group fractions, and lipid hydroperoxides in LC patients. Genotyping was carried out by PCR-RFLP. In LC patients with TT genotype, Cu, Zn-superoxide dismutase activities and nonprotein thiol levels were significantly higher than the controls. In patients with GT and GG genotype, high levels of lipid hydroperoxides showed statistical significance when compared to controls. Our results indicate a potential relationship among G894T polymorphism of NOS3, and impaired redox homeostasis. Further studies are required to determine the role of NOS3 gene polymorphism and impaired plasma redox homeostasis.

Effect of dietary zinc level on growth, enzyme activity and body trace elements of hybrid tilapia,Oreochromis niloticus × O. aureus, fed soya bean meal-based diets

A feeding experiment was conducted to determine the dietary zinc (Zn) requirement of hybrid tilapia fed on a diet with soya bean meal as the sole protein source. The quantity of phytic acid in the experimental diet was 15.5 g kg−1. Juvenile hybrid tilapia were fed on diets containing 31–227 mg Zn kg−1 in triplicates for 6 weeks. Haematology of the fish was not affected by various dietary Zn levels. Fish fed on a diet containing 31 mg kg−1 endogenous Zn showed the lowest growth rates, feed utilization, and body and plasma Zn levels. Weight gain (WG), plasma Zn level and superoxide dismutase (SOD) activity increased when a higher quantity of dietary Zn of 127 mg kg−1 was administered to the experimental fish. Beyond this level, the values of these parameters were relatively stable. On the other hand, within the dietary Zn range tested, whole-body Zn and ash increased with higher dietary Zn levels. Analysis using a broken-line model showed that the dietary Zn requirements of hybrid tilapia fed on soya bean meal-based diets containing 15.5 g kg−1 endogenous phytic acid were 115, 115 and 105 mg kg−1 based on WG, whole-body Zn retention and plasma Zn level, respectively.

Blueberry treatment decreased D-galactose-induced oxidative stress and brain damage in rats.

D-galactose (GAL) causes aging-related changes and oxidative stress in the organism. We investigated the effect of whole fresh blueberry (BB) (Vaccinium corymbosum L.) treatment on oxidative stress in age-related brain damage model. Rats received GAL (300 mg/kg; s.c.; 5 days per week) alone or together with 5 % (BB1) and 10 % (BB2) BB containing chow for two months. Malondialdehyde (MDA),protein carbonyl (PC) and glutathione (GSH) levels, and Cu Zn-superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and glutathione transferase (GST) activities as well as acetylcholinesterase (AChE) activities were determined. Expressions of B cell lymphoma-2 (Bcl-2), Bax and caspase-3 were also evaluated in the brain by immunohistochemistry. MDA and PC levels and AChE activity increased, but GSH levels, SOD and GSH-Px activities decreased together with histopathological structural damage in the brain of GAL-treated rats. BB treatments, especially BB2 reduced MDA and PC levels and AChE activity and elevated GSH levels and GSH-Px activity. BB1 and BB2 treatments diminished apoptosis and ameliorated histopathological findings in the brain of GAL-treated rats. These results indicate that BB partially prevented the shift towards an imbalanced prooxidative status and apoptosis together with histopathological amelioration by acting as an antioxidant (radical scavenger) itself in GAL-treated rats.

Role of lipid peroxidation products, plasma total antioxidant status, and Cu-, Zn-superoxide dismutase activity as biomarkers of oxidative stress in elderly prediabetics.

The relationship between hyperglycemia and oxidative stress in diabetes is well known, but the influence of metabolic disturbances recognized as prediabetes, in elderly patients especially, awaits for an explanation. Methods. 52 elderly persons (65 years old and older) with no acute or severe chronic disorders were assessed: waist circumference (WC), body mass index (BMI), percentage of body fat (FAT), and arterial blood pressure. During an oral glucose tolerance test (OGTT) fasting (0′) and 120-minute (120′) glycemia and insulinemia were determined, and type 2 diabetics (n = 6) were excluded. Subjects were tested for glycated hemoglobin HbA1c, plasma lipids, total antioxidant status (TAS), thiobarbituric acid-reacting substances (TBARS), and activity of erythrocyte superoxide dismutase (SOD-1). According to OGTT results, patients were classified as normoglycemics, (NGT, n = 18) and prediabetics, (PRE, n = 28). Results. Both groups did not differ with their lipids, FAT, and TBARS. PRE group had higher WC (P < 0.002) and BMI (P < 0.002). Lower SOD-1 activity (P < 0.04) and TAS status (P < 0.04) were found in PRE versus NGT group. Significance. In elderly prediabetics, SOD-1 and TAS seem to reflect the first symptoms of oxidative stress, while TBARS are later biomarkers of oxidative stress.

Identification of [CuCl(acac)(tmed)], a copper(II) complex with mixed ligands, as a modulator of Cu,Zn superoxide dismutase (Sod1p) activity in yeast

Superoxide dismutases (SODs) stand in the prime line of enzymatic antioxidant defense in nearly all eukaryotic cells exposed to oxygen, catalyzing the breakdown of the superoxide anionic radical to O(2) and H(2)O(2). Overproduction of superoxide correlates with numerous pathophysiological conditions, and although the native enzyme can be used as a therapeutic agent in superoxide-associated conditions, synthetic low molecular weight mimetics are preferred in terms of cost, administration mode, and bioavailability. In this study we make use of the model eukaryote Saccharomyces cerevisiae to investigate the SOD-mimetic action of a mononuclear mixed-ligand copper(II) complex, [CuCl(acac)(tmed)] (where acac is acetylacetonate anion and tmed is N,N,N',N'-tetramethylethylenediamine). Taking advantage of an easily reproducible phenotype of yeast cells which lack Cu-Zn SOD (Sod1p), we found that the compound could act either as a superoxide scavenger in the absence of native Sod1p or as a Sod1p modulator which behaved differently under various genetic backgrounds.

UV Released Factors Induce Antioxidant Defense in A375 Cells

UV light leads to release of different secretory factors from irradiated cells of which some of them have been characterized. We have reported earlier that cells exposed to the supernatant medium from irradiated cells were resistant to killing by some genotoxic agents. In this study, we present our finding that demonstrates DNA damage induced by UV or H(2)O(2) is lowered on prior exposure to the UV released factors (UVRF). Production of ROS in cells and lipid peroxidation was also lowered. It was found that treatment of unexposed cells with UVRF present in the supernatant medium altered the antioxidant defense activity in cells. Significant was the increase in catalase (CAT) and Cu-Zn superoxide dismutase (SOD) activity, whereas glutathione peroxidase (GPx) and reduced glutathione (GSH) levels remained unaffected. Cells exposed to UVRF prior to UV or H(2)O(2) treatment also experienced such upregulation; however, the remarkable increase in the GPx activity exhibited by these cells was not observed in cells exposed to H(2)O(2) or UV alone. It appears that exposure to UVRF tinkered with antioxidant defense in cells to facilitate its proliferation upon assault by an agent that can produce oxidative damage.

Role of the cellular prion protein in the neuron adaptation strategy to copper deficiency.

Copper transporter 1 (CTR1), cellular prion protein (PrP(C)), natural resistance-associated macrophage protein 2 (NRAMP2) and ATP7A proteins control the cell absorption and efflux of copper (Cu) ions in nervous tissues upon physiological conditions. Little is known about their regulation under reduced Cu availability, a condition underlying the onset of diffused neurodegenerative disorders. In this study, rat neuron-like cells were exposed to Cu starvation for 48 h. The activation of Caspase-3 enzymes and the impairment of Cu,Zn superoxide dismutase (Cu,Zn SOD) activity depicted the initiation of a pro-apoptotic program, preliminary to the appearance of the morphological signs of apoptosis. The transcriptional response related to Cu transport proteins has been investigated. Notably, PrP(C) transcript and protein levels were consistently elevated upon Cu deficiency. The CTR1 protein amount was stable, despite a two-fold increase in the transcript amount, meaning the activation of post-translational regulatory mechanisms. NRAMP2 and ATP7A expressions were unvaried. The up-regulated PrP(C) has been demonstrated to enhance the cell Cu uptake ability by about 50% with respect to the basal transport, and so sustain the Cu delivery to the Cu,Zn SOD cuproenzymes. Conclusively, the study suggests a pivotal role for PrP(C) in the cell adaptation to Cu limitation through a direct activity of ion uptake. In this view, the PrP(C) accumulation observed in several cancer cell lines could be interpreted as a molecular marker of cell Cu deficiency and a potential target of therapeutic interventions against disorders caused by metal imbalances.

Differences Between Original Intravenous Iron Sucrose and Iron Sucrose Similar Preparations

Iron sucrose (Venofer; reference) has a good safety record and is prescribed in patients with anaemia and chronic kidney disease worldwide, but various iron sucrose similar (ISS) preparations are now utilized in clinical practice. This study evaluates possible differences between iron sucrose and ISS preparations on haemodynamic and oxidative stress markers in normal rats. 60 male and 60 female Sprague Dawley rats were divided into four groups and assigned to receive commercially available ISS test 1, ISS test 2, reference or isotonic saline solution (control). A single i.v. dose of iron (40 mg/kg) or saline (equivalent volume) was administered after 24 h and every 7 days for 4 weeks. Blood samples were collected for biological assessment of haemoglobin (Hb), serum iron and percentage transferrin saturation (TSAT), and urine samples were collected to investigate creatinine clearance and proteinuria. Animals were sacrificed after receiving an i.v. dose on days 1, 7 and 28, and kidney, liver, and heart homogenates were then collected to determine antioxidant enzyme levels. Tissues were processed using Prussian blue and immmunohistochemistry techniques to identify iron deposits, tissue ferritin and pro-inflammatory markers. Systolic blood pressure was significantly reduced in the ISS groups relative to the reference and control groups after 24 h and on days 7, 14 and 21 (p < 0.05). Creatinine clearance was reduced (p < 0.01) and proteinuria marked (p < 0.01) in the ISS groups at 24 h and on days 7 and 28 relative to the reference and control groups which did not differ throughout the study. Liver enzymes were also increased in the ISS groups at 24 h and on days 7 and 28. Both ISS test 1 and ISS test 2 groups presented a significant increase in catalase, thiobarbituric reactive species, Cu, Zn-superoxide dismutase (CuZnSOD) and glutathione peroxidase activity, and a decrease in glutathione levels (p < 0.01) in the liver, heart and kidney at 24 h and on day 7 relative to the reference and control groups. Serum iron and percentage TSAT were elevated in all groups (except control) (p < 0.01) but no differences in Hb concentration were observed between them. Finally, levels of the proinflammatory markers TNF-alpha and IL6 were significantly elevated in the ISS groups (liver, heart and kidney) compared with the reference and control groups on day 28 (p < 0.01). These findings suggest significant differences between the reference and ISS test 1/ISS test 2 regarding oxidative stress and the inflammatory responses of liver, heart and kidneys in normal rats. A possible explanation for these observations could be the stability of the iron complex.

Quercetin activates AMP‐activated protein kinase by reducing PP2C expression protecting old mouse brain against high cholesterol‐induced neurotoxicity

It is known that a high-cholesterol diet induces oxidative stress, inflammatory response, and beta-amyloid (Abeta) accumulation in mouse brain, resulting in neurodegenerative changes. Quercetin, a naturally occurring flavonoid, has been reported to possess numerous biological activities beneficial to health. Our previous studies have demonstrated that quercetin protects mouse brain against D-galactose-induced oxidative damage. Against this background, we evaluated the effect of quercetin on high-cholesterol-induced neurotoxicity in old mice and explored its potential mechanism. Our results showed that oral administration of quercetin significantly improved the behavioural performance of high-cholesterol-fed old mice in both a step-through test and the Morris water maze task. This is at least in part caused by decreasing ROS and protein carbonyl levels and restoring Cu--Zn superoxide dismutase (Cu, Zn-SOD) activity. Furthermore, quercetin also significantly activated the AMP-activated protein kinase (AMPK) via down-regulation of protein phosphatase 2C (PP2C), which reduced the integral optical density (IOD) of activated microglia cells and CD11b expression, down-regulated iNOS and cyclooxygenase-2 (COX-2) expression, and decreased IL-1beta, IL-6, and TNF-alpha expression in the brains of high-cholesterol-fed old mice through the suppression of NF-kappaB p65 nuclear translocation. Moreover, AMPK activation significantly increased 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase and acetyl-CoA carboxylase (ACC) phosphorylation and reduced fatty acid synthase (FAS) expression in the brains of high-cholesterol-fed old mice, which reduced cholesterol levels, down-regulated cholesterol 24-hydroxylase (CYP46A1) and beta-amyloid converting enzyme 1 (BACE1) expression, decreased eukaryotic translation initiation factor 2alpha (eIF2alpha) phosphorylation, and lowered Abeta deposits. However, the neuroprotective effect of quercetin was weakened by intraperitoneal injection of compound C, an AMPK inhibitor. These results suggest that AMPK activated by quercetin may be a potential target to enhance the resistance of neurons to age-related diseases.