The effect of taurine supplementation on oxidative stress in experimental hypothyroidism

The purpose of this study was to investigate the oxidative status in experimental hypothyroidism and the antioxidant effect of taurine supplementation. Forty male Sprague Dawley rats were randomly divided into four groups (group 1, control; group 2, control + taurine; group 3, propylthiouracil (PTU); group 4, PTU + taurine). Hypothyroidism was induced by giving 0.05% PTU in drinking water for 8 weeks. Taurine was supplemented in drinking water at a concentration of 1% for 5 weeks. Plasma (p < 0.05), red blood cell (p < 0.01), liver (p < 0.001) and kidney tissue (p > 0.05) malondialdehyde levels were increased in the PTU group compared with those of the control rats and were decreased in the PTU + taurine group compared with the PTU alone group. No significant changes were observed in glutathione levels of kidney and liver in the PTU group, but taurine supplementation significantly increased the glutathione levels of these tissues. Paraoxonase and arylesterase activities were decreased in the PTU group while taurine supplementation caused no significant changes in paraoxonase and arylesterase activities. These findings suggest that taurine supplementation may play a protective role against the increased oxidative stress resulting from hypothyroidism.     

Early evolution of selenium status and oxidative stress parameters in rat models of thermal injury

The objective of the present study was to measure the relationship between selenium status and oxidative stress in two rat models of thermal injury. A non-lethal third-degree burn injury involving 20% (experiment 1) or 40% (experiment 2) of total body surface area (TBSA) was applied to male Wistar rats. Selenium level, glutathione peroxidase (GPx) activity in plasma, red blood cells (RBC) and tissues (liver, kidney, muscle, and brain), and plasma selenoalbumin (Se-alb) were measured in control rats and in burned rats respectively 6 hours after injury and daily from day 1 to day 5. In parallel, lipid and protein oxidative damages, monitored by plasma and tissue thiobarbituric acid reactive species (TBARs) levels and plasma total thiol groups were assessed.

We observed a decrease of plasma Se and Se-albumin 6 hours after burn injury. In parallel, plasma GPx activity rapidly decreased and remained significantly lower than in control rats. These alterations were enhanced by the burn injury severity. Plasma TBARs followed the same pattern as that of plasma cholesterol, with an initial decrease and an increase at day 3 in 40% TBSA burned rats. Plasma thiol groups decreased in the two experiments indicating plasma protein oxidation.

These results confirm an early oxidative stress in burn injury, and suggest an early selenium mobilization, which might counteract this oxidative stress. These data underline the crucial need of a restored selenium status in burned patients immediately after the burn injury.     

Influence of age on lead-induced oxidative stress in rat

Influence of age on lead-induced oxidative stress was investigated in young, adult, and old rats maintained on 0.2% lead acetate (2000 ppm lead) in drinking water for 3 mo. The lead-induced depletion of blood and liver reduced glutathione was about equal in young and adult but not in old rats. The increases in blood, liver, and brain oxidized glutathione and blood and liver superoxide dismutase levels were related to the accumulation of lead in these tissues and followed the order young >adult>old. The lead-induced inhibition of blood δ-aminolevulinic acid dehydratase activity, lowering in hemoglobin, and enhanced urinary excretion of δ-aminolevulinic acid were independent of variation in age. The results indicate that young rats may be most sensitive, whereas old rats may be most resistant to some of the oxidative effects of lead examined, which may be related to the accumulation of lead.     

干旱胁迫对不同葡萄砧木光合特性和荧光参数的影响

干旱胁迫导致葡萄砧木实生苗叶片光合能力下降.在正常供水和轻度干旱下,砧木的P_n 以3309C最高,其次是1103P,420A较低,各砧木的G_s和T_r差异不显著;中度干旱下,则以1103P的P_n最高,3309C最低;而严重干旱胁迫下,1103P的P_n比3309C高出124%,水分利用效率是3309C的1.95倍.干旱胁迫下,3种砧木的共同趋势是可变荧光 (F_o) 升高,最大荧光 (F_m)、实际光能转化效率 (ФPSⅡ）和可变荧光与最大荧光比 (F_v/F_m) 降低,但品种变幅不同.中度干旱使3309C的F _o升高17.1%,F_v/F_m降低了8.5%,而1103P的F_o升高6.8%,F_v/F_m降低了5.8%;严重干旱则使3309C的F_o升高36.2%,F_v/F_m降低了20.1%,而1103P的F_o升高9.9%,F_v/F_m降低了10.2%.干旱胁迫对不同葡萄砧木光合和荧光参数的影响与其抗旱性密切相关,其中F_v/F_m和P_n的相关系数最大（r=0.9883）.     

Higher in vitro resistance to oxidative stress in extra-pair offspring

Oxidative stress is considered to act as a universal physiological constraint in life-history evolution of animals. This should be of interest for extra-pair paternity behaviour, and we tested here the prediction that offspring arising from extra-pair matings of female great tits show higher resistance to oxidative stress than within-pair offspring. Resistance to oxidative stress, measured as the whole blood resistance to a controlled free-radical attack, was significantly higher for extra-pair offspring as predicted although these were not heavier or in better body condition than within-pair offspring. Since resistance to oxidative stress has been suggested to enhance survival and reproductive rates, extra-pair offspring with superior resistance to oxidative stress, be it through maternal effects or paternal inheritance, may achieve higher fitness and thus provide significant indirect fitness benefits to their mothers. In addition, because oxidative stress affects colour signals and sperm traits, females may also gain fitness benefits by producing sons that are more attractive (sexy-sons hypothesis) and have sperm of superior quality (sexy-sperm hypothesis). Heritability of resistance to oxidative stress as well as maternal effects may both act as proximate mechanisms for the observed result. Disentangling these two mechanisms would require an experimental approach. Future long-term studies should also aim at experimentally testing whether higher resistance to oxidative stress of EP nestlings indeed translates into fitness benefits to females.     

Apple juice attenuates genotoxicity and oxidative stress induced by cadmium exposure in multiple organs of rats

The aim of this study was to evaluate the health benefits associated with apple consumption following cadmium exposure. A total of 15 Wistar rats were distributed into three groups (n = 5), as follows: control group (non-treated group, CTRL); cadmium group (Cd) and apple juice group (Cd + AJ). The results showed a decrease in the frequency micronucleated cells in bone marrow and hepatocytes in the group exposed to cadmium and treated with apple juice. Apple juice was also able to reduce the 8OHdG levels and to decrease genetic damage in liver and peripheral blood cells. Catalase (CAT) was decreased following apple juice intake. Taken together, our results demonstrate that apple juice seems to be able to prevent genotoxicity and oxidative stress induced by cadmium exposure in multiple organs of Wistar rats.     

Effect of oxidative stress on rat thyrocyte iodide metabolism

Thyroid cells fall into the type of cells functioning during continuous production of high H(2)O(2) concentrations. We studied the effect of H(2)O(2)-induced oxidative stress (0.1, 1.0 and 10.0 mM) on the activities of the key steps of iodide metabolism (uptake, oxidation and organification) in thyrocytes cultivated in an organ culture. After 60 min cultivation of cells in a medium containing H(2)O(2) at concentrations of 1.0 and 10.0 mM iodide (I(-)) uptake, thyroperoxidase (TPO) activity and I(-) organification were completely inhibited. No restoration of the parameters studied was observed within the subsequent 24 h of cultivation. The inhibitory effect of 0.1 mM H(2)O(2) was reversible. Activation of I(-) uptake in the cultivated tissue and a 520-880% increase of the total I(-) content were observed after 8 and 24 h. The concentration of I(-) protein-bound fraction was raised by 220% after 24 h. A biphasic effect of 0.1 mM H(2)O(2) on TPO was observed: 76.2% and 72.2% inhibitions were seen after 2 and 8 h, respectively, whereas 40.0% enzyme activation was after 5 h. TPO activity was partially restored after 24 h and amounted to 65% of the initial value. The significant increase in the concentration of iodide protein-bound fraction, which was observed simultaneously with TPO inhibition, could be due to thyroglobulin non-enzymic iodination under H(2)O(2)-generated oxidative stress. The data obtained indicate that iodide oxidation, as a step in the biosynthesis of thyroid hormones, was most sensitive to oxidative stress activation. The impaired iodide uptake and its organification during oxidative stress can play a pathogenetic role in disturbed functions of thyroid cells.     

Neuroprotective and anticonvulsant effects of organic and conventional purple grape juices on seizures in Wistar rats induced by pentylenetetrazole

Epilepsy is the most common neurological disorder worldwide. Studies have shown that recurrent seizures may increase the concentration of reactive oxygen species, which can lead to oxidative stress and neuronal damage. These seizures result in substantial deleterious effects on an individual's health. Organic and conventional grape juices are rich in polyphenols, compounds with important antioxidant activity. However, these juices could have differences in their polyphenol content. The aim of this study was to investigate the neuroprotective and anticonvulsant effects of organic and conventional grape juice treatments in Wistar rats against pentylenetetrazole (a convulsant drug)-induced damage. In addition, we evaluated potential behavioral changes in rats treated with the juices and the polyphenolic profile of those samples. Animals (n=16 in each group) received treatment with saline, organic or conventional grape juice for 17 days. On the eighteenth day, behavioral changes were evaluated by an open field test. Afterwards, half of the rats from each group received pentylenetetrazole and were observed for 30 min to evaluate possible seizure characteristics. The animals were subsequently killed by decapitation and their hippocampus, cerebellum and cerebral cortex tissues were isolated. The results of this study showed that neither organic nor conventional grape juice altered the behavior parameters, and no statistical differences were observed in the seizure characteristics of the groups. Nevertheless, both juice types were able to protect from lipid and protein oxidative damage, decrease nitric oxide content and increase enzymatic (superoxide dismutase and catalase) and non-enzymatic (sulfhydryl protein) antioxidant defenses in brain tissues following pentylenetetrazole-induced seizures. In general, organic juice showed superior results in each test, probably due to its higher polyphenol content relative to conventional juice. These results indicate that grape juices can provide further insight into natural neuroprotective compounds and may lead to the development of new therapeutic strategies for epileptic patients.     

Cytoprotective effect of phloroglucinol on oxidative stress induced cell damage via catalase activation

We investigated the cytoprotective effect of phloroglucinol, which was isolated from Ecklonia cava (brown alga), against oxidative stress induced cell damage in Chinese hamster lung fibroblast (V79-4) cells. Phloroglucinol was found to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydrogen peroxide (H(2)O(2)), hydroxy radical, intracellular reactive oxygen species (ROS), and thus prevented lipid peroxidation. As a result, phloroglucinol reduced H(2)O(2) induced apoptotic cells formation in V79-4 cells. In addition, phloroglucinol inhibited cell damage induced by serum starvation and radiation through scavenging ROS. Phloroglucinol increased the catalase activity and its protein expression. In addition, catalase inhibitor abolished the protective effect of phloroglucinol from H(2)O(2) induced cell damage. Furthermore, phloroglucinol increased phosphorylation of extracellular signal regulated kinase (ERK). Taken together, the results suggest that phloroglucinol protects V79-4 cells against oxidative damage by enhancing the cellular catalase activity and modulating ERK signal pathway.     

Lindane-induced liver oxidative stress: respiratory alterations and the effect of desferrioxamine in the isolated perfused rat liver

The effects of lindane administration (25-60 mg kg-1 for 24 h) on hepatic oxygen consumption were studied in the isolated perfused rat liver, in the absence and presence of the iron-chelator free-radical scavenger desferrioxamine. Lindane elicits a dose-dependent enhancement of total oxygen uptake by the liver, which is largely inhibited by 0.55 mM desferrioxamine. Total desferrioxamine- sensitive oxygen consumption exhibits a maximal increase (213 per cent) at 60 mg of lindane kg-1 over control values and represents 21 per cent of the total oxygen consumption. At the different doses of lindane used, it was calculated that about 60 per cent of the total increase in oxygen uptake by the liver is accounted for by oxygen related to oxidative stress, probably utilized at different stages of the induced lipid peroxidative process.     

Protective effects of ascorbic acid on hepatotoxicity and oxidative stress caused by carbon tetrachloride in the liver of Wistar rats

This study was planned to investigate the protective effect of l (+)‐ascorbic acid (Vit C) on CCl₄‐induced hepatotoxicity and oxidative stress in the liver of Wistar rats (Rattus Norvegicus, strain Wistar). Twenty‐four adult male Wistar rats were fed with standard rat chow diet for 10 days and randomly were divided into four groups of six each as follows: (1) control, (2) CCl₄, (3) “CCl₄ + Vit C”, (4) Vit C groups. CCl₄ was applied to rats belonging to CCl₄ and “CCl₄ + Vit C” groups subcutaneously at 1 mg kg^?1 dose CCl₄ for 3 days. Vit C applied to “CCl₄ + Vit C” and “Vit C” group rats intraperitoneally at 300 mg kg^?1 dose for 3 days. All rats were sacrificed and livers were quickly removed on the fourth day of the experiment. MDA, total glutathione (T.GSH) levels and superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH‐PX) activities were measured in the liver of all groups of rats and also serum alanine amino transferase (ALT) and aspartate amino transferase (AST) activities were detected to determine liver functions in all groups of rats. Histopathological changes were evaluated by light and transmission electron microscopes. In “CCl₄ + Vit C” group, MDA level was significantly decreased (p < 0.05) and SOD, CAT, GSH‐PX activities were significantly increased (p < 0.005, 0.01, 0.05) respectively, T.GSH level was significantly increased (p < 0.005) and serum ALT and AST activities were significantly decreased (p < 0.01, 0.05), respectively, when compared with CCl₄ group. These results show that Vit C has a highly protective effect on hepatotoxicity and oxidative stress caused by CCl₄. Copyright © 2009 John Wiley & Sons, Ltd.     

Characterization of oxidative stress in blood from diabetic vs. hypercholesterolaemic patients, using a novel synthesized marker

In the present study, we extend our novel concept of designing and using exogenous markers for the characterization of oxidative stress (OS) and OS-associated diseases. The aim was to use such a synthetic compound as a tool for studying OS in blood from diabetic and hypercholesterolaemic (Hc) patients. The marker used N-linoleoyl tyrosine (LT) was constructed from tyrosine and linoleic acid (LA); both components are known to be easily oxidized upon exposure to different types of reactive oxygen/nitrogen species (ROS/RNS), and to generate specific oxidized products, depending on the type of oxidants present in vivo. Using the LT probe, we showed that the ratios of oxidized LT to total LT (Ox-LT/LT) is significantly higher in blood samples obtained from diabetic patients, than in Hc patients or healthy control subjects. LC/MS analysis revealed that blood from diabetic patients oxidizes the marker with predominant formation of Ox-LT hydroperoxide (LT-OOH) and epoxide (epoxy-LT), where the LA moiety is oxidized to hydroperoxide and to epoxide, respectively. Analysis of oxysterol levels in these samples (GC/MS) revealed that the blood of both diabetic and Hc patients contained significantly more oxysterols than blood of control subjects. Consumption of pomegranate juice by diabetic patients for 3 months suppressed their blood capacity to oxidize the LT and similarly also reduced their blood oxysterol/total cholesterol ratio by 93%. The use of an exogenous marker to characterize OS in blood samples yields important information on the extent of OS, and can provide a fingerprint for the early identification of different pathological conditions associated with OS.     

Characterization of oxidative stress in blood from diabetic vs. hypercholesterolaemic patients,using a novel synthesized marker

In the present study, we extend our novel concept of designing and using exogenous markers for the characterization of oxidative stress (OS) and OS-associated diseases. The aim was to use such a synthetic compound as a tool for studying OS in blood from diabetic and hypercholesterolaemic (Hc) patients. The marker used N-linoleoyl tyrosine (LT) was constructed from tyrosine and linoleic acid (LA); both components are known to be easily oxidized upon exposure to different types of reactive oxygen/nitrogen species (ROS/RNS), and to generate specific oxidized products, depending on the type of oxidants present in vivo. Using the LT probe, we showed that the ratios of oxidized LT to total LT (Ox-LT/LT) is significantly higher in blood samples obtained from diabetic patients, than in Hc patients or healthy control subjects. LC/MS analysis revealed that blood from diabetic patients oxidizes the marker with predominant formation of Ox-LT hydroperoxide (LT-OOH) and epoxide (epoxy-LT), where the LA moiety is oxidized to hydroperoxide and to epoxide, respectively. Analysis of oxysterol levels in these samples (GC/MS) revealed that the blood of both diabetic and Hc patients contained significantly more oxysterols than blood of control subjects. Consumption of pomegranate juice by diabetic patients for 3 months suppressed their blood capacity to oxidize the LT and similarly also reduced their blood oxysterol/total cholesterol ratio by 93%. The use of an exogenous marker to characterize OS in blood samples yields important information on the extent of OS, and can provide a fingerprint for the early identification of different pathological conditions associated with OS.     

Melatonin effect on renal oxidative stress under constant light exposure

Recently, numerous studies have shown antioxidant actions of melatonin. Melatonin at both physiological and pharmacological levels stimulates glutathione peroxidase, glutathione reductase and superoxide dismutase activities in the brains of rats and chickens. This study was designed to evaluate the effect of melatonin on nephropathy and oxidative stress under constant light exposure. Nephropathy was induced by adriamycin administered in a single dose (25 mg kg(-1) b.w., i.p.). Melatonin was injected i.p. (1,000 microg kg(-1) b.w./day). Malondialdehyde, reduced glutathione, glutathione peroxidase, glutathione reductase, glutathione transferase, catalase and superoxide dismutase were determined in kidney. Urea, creatinine and total proteins in plasma and proteinuria were evaluated and melatonin was determined. Results show a decrease in melatonin levels. Similar effects occurred with the antioxidant enzyme activities and reduced glutathione. Likewise, adriamycin and constant light induced significant enhancement of malondialdehyde. All changes induced both by adriamycin and constant light were reverted to normal by melatonin administration. Constant light exposure was associated with an increase in oxidative stress and nephropathy induced by adriamycin. Treatment with melatonin decreased lipid peroxides, and permitted a recovery of reduced glutathione, scavenger enzyme activity and parameters of renal function.     

Prolonged swimming promotes cellular oxidative stress and p66Shc phosphorylation,but does not induce oxidative stress in mitochondria in the rat heart

Abstract

Exercise-induced changes in p66Shc-dependent signaling pathway are still not fully understood. The p66Shc protein is one of the key players in cell signaling, particularly in response to oxidative stress. Therefore, the aim of this study was to investigate the effect of prolonged swimming on the phosphorylation of p66Shc as well as the induction of mitochondrial and cellular oxidative stress in rat hearts.

Male Wistar rats were divided into a sedentary control group and an exercise group. The exercised rats swam for 3 hours and were burdened with an additional 3% of their body weight. After the cessation of exercise, their hearts were removed immediately for experiments.

The exercise protocol caused increased levels of the following oxidative stress parameters in cardiac cells: DNA damage, protein carbonyls, and lipid dienes. There was also increased phosphorylation of p66Shc without any alterations in Akt and extracellular signal-regulated kinases. Changes in the ferritin L levels and the L to H subunit ratio were also observed in the exercised hearts compared with the control hearts. Despite increased phosphorylation of p66Shc, no significant increase was observed in either mitochondrial H₂O₂ release or mitochondrial oxidative stress markers. Regardless of the changes in phosphorylation of p66Shc, the antioxidant enzyme activities (superoxide dismutase and catalase) and anti-apoptotic (Bcl2), and pro-apoptotic (Bax) protein levels were not affected by prolonged swimming. Further studies are required to investigate whether p66Shc phosphorylation is beneficial or detrimental to cardiac cells after exercise cessation.     

Assessment of some oxidative stress parameters in patients with bronchial asthma after selenium supplementation

The goal of this study was to investigate the effect of selenium deficit replenishment in patients with bronchial asthma (BA) on manifestations of oxidative stress and conditions of the antioxidant system (AOS). The need of correction of selenium deficit in BA-patients is determined by increased requirements in antioxidants due to chronic inflammatory process responsible for pathogenesis of BA. Latvia as well as Eastern Finland, Byelorussia, some regions of Ukraine, North-Western Russia, and New Zealand belong to the endemic areas with marked selenium deficit in soils and foodstuff. Twenty patients (7 men and 13 women) with selenium deficit and verified diagnosis of BA have been examined. In addition to basic therapy all patients received organic selenium as SelenoPRECISE (PharmaNord) 200 μg daily for 16 weeks. This caused statistically significant increase of plasma selenium from 50.94 ± 7.58 to 63.59 ± 10.87 μg/l (p < 0.001), the increase of selenium-dependent glutathione peroxidase (from 38.64 ± 10.72 U/g Hb to 58.57 ± 14.64 U/g Hb, p = 0.01). Treatment of patients with selenium also normalized the parameters characterizing oxidative stress (chemiluminescence), significantly exceeded normal values before this treatment. The use of selenium in addition to basic therapy allows to abolish or reduce oxidative stress by correcting the antioxidant system.     

Neuroprotective effect of melatonin on radiation-induced oxidative stress and apoptosis in the brainstem of rats

This study aimed to determine the effects of melatonin on irradiation-induced apoptosis and oxidative stress in the brainstem region of Wistar rats. Therefore, the animals underwent whole-brain X-radiation with a single dose of 25 Gy in the presence or absence of melatonin pretreatment at a concentration of 100 mg/kg BW. The rats were allocated into four groups (10 rats in each group): namely, vehicle control (VC), 100 mg/kg of melatonin alone (MLT), irradiation-only (RAD), and irradiation plus 100 mg/kg of melatonin (RAM). An hour before irradiation, the animals received intraperitoneal (IP) melatonin and then were killed after 6 hr, followed by measurement of nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), and total antioxidant capacity (TAC) in the brainstem region. Furthermore, the western blot analysis technique was performed to assess the caspase-3 expression level. Results showed significantly higher MDA and NO levels in the brainstem tissues for the RAD group when compared with the VC group (p < .001). Moreover, the irradiated rats exhibited a significant decrease in the levels of CAT, SOD, GPx, and TAC (p < .01, p < .001, p < .001, and p < .001, respectively) in comparison to the VC group. The results of apoptosis assessment revealed that the expression level of caspase-3 significantly rose in the RAD group in comparison with the VC group (p < .001). Pretreatment with melatonin ameliorated the radiation-induced adverse effects by decreasing the MDA and NO levels (p < .001) and increasing the antioxidant enzyme activities (p < .001). Consequently, the caspase-3 protein expression level in the RAM group showed a significant reduction in comparison with the RAD group (p < .001). In conclusion, melatonin approximately showed a capacity for neuroprotective activity in managing irradiation-induced oxidative stress and apoptosis in the brainstem of rats; however, the use of melatonin as a neuroprotective agent in humans requires further study, particularly clinical trials.     

Protective effect of silymarin on oxidative stress in rat brain

Brain is susceptible to oxidative stress and it is associated with age-related brain dysfunction. Previously, we have pointed out a dramatic decrease of glutathione levels in the rat brain after acetaminophen (APAP) oral administration overdose. Silymarin (SM) is a mixture of bioactive flavonolignans isolated from Silybum marianum (L.) Gaertn., employed usually in the treatment of alcoholic liver disease and as anti-hepatotoxic agent in humans. In this study, we have evaluated the effect of SM on enzymatic and non enzymatic antioxidant defensive systems in rat brain after APAP-induced damage. Male albino Wistar rats were treated with SM (200 mg/kg/die orally) for three days, or with APAP single oral administration (3 g/kg) or with SM (200 mg/kg/die orally) for 3 days and APAP single oral administration (3 g/kg) at third day. Successively the following parameters were measured: reduced and oxidized glutathione (GSH and GSSG), ascorbic acid (AA), enzymatic activity variations of superoxide dismutase (SOD) and malondialdehyde levels (MDA). Our results showed a significant decrease of GSH levels, AA levels and SOD activity and an increase of MDA and GSSG levels after APAP administration. After SM administration GSH and AA significantly increase and SOD activity was significantly enhanced. In the SM+APAP group, GSH values significantly increase and the others parameters remained unchanged respect to control values. These results suggest that SM may to protect the SNC by oxidative damage for its ability to prevent lipid peroxidation and replenishing the GSH levels.