Thyroid hormone-induced haemoglobin changes and antioxidant enzymes response in erythrocytes

Thyroid hormones modulate haemoglobin and reactive oxygen species (ROS) production, leading to antioxidant changes. This study evaluated the antioxidant response to ROS in erythrocytes in hypothyroid and hyperthyroid rats. Wistar rats were divided into four groups: control; hyperthyroid (T4-12 mg 1(-1) in drinking water); sham operated (simulation of thyroidectomy); and hypothyroid (thyroidectomized). Four weeks after, blood was collected and haemoglobin and T(4) levels, lipid peroxidation (LPO), protein oxidation, superoxide dismutase (SOD), catalase (CAT) , glutathione S-transferase (GST) and glutathione peroxidase (GPx) activities, and total radical antioxidant potential (TRAP) were measured. SOD, CAT and GST immunocontent was evaluated. Haemoglobin levels were increased in hyperthyroid erythrocytes. LPO and carbonyls were augmented (65% and 55%, respectively) in hyperthyroid and reduced (31% and 56%, respectively) in hypothyroid group. SOD and CAT activities have not changed, as well as CAT immunocontent. TRAP was diminished in both hyperthyroid and hypothyroid groups (36% and 37%, respectively). GST activity and immunocontent, as well as GPx activity, were increased in hyper and hypothyroid rats. The data suggest that thyroid hormone changes determine ROS concentration changes and decrease of some antioxidant defences that would lead to a compensatory answer of the GST and GPx enzymes, which could be consider as credible biomarkers.     

Protective effects of vitamin E and curcumin on L-thyroxine-induced rat testicular oxidative stress

Present study examines effects of curcumin and vitamin E on oxidative stress parameters, antioxidant defence enzymes and oxidized (GSSG) and reduced glutathione (GSH) levels in testis of L-thyroxine (T4)-induced hyperthyroid rats. The oxidative stress in T4-treated rat testis was evident from elevation in oxidative stress parameters such as lipid peroxide and protein carbonyl contents, decrease in superoxide dismutase (SOD) and catalase (CAT) activities and increase in glutathione peroxidase (GPx) activity. This is accompanied with decrease in number and mortality of epididymal sperms. When the T4-treated rats were fed with vitamin E and/or curcumin, the lipid peroxide and protein carbonyl contents in crude homogenates of testes decreased to normal level. Treatment of curcumin and/or vitamin E to T4-treated rats resulted in elevation of SOD level in postmitochondrial fraction (PMF) and mitochondrial fraction (MF) and CAT in PMF, with decreased GPx activity in MF. However, curcumin or vitamin E was unable to change GPx activity alone but in together they elevated the GPx in PMF of T4-treated rat testis. Both the antioxidants are incapable of producing significant changes in GSH:GSSG ratio of PMF of T4-treated rats. In MF, GSH:GSSG ratio elevated and decreased respectively by curcumin and vitamin E treatments to T4-treated rats, however, in together these antioxidants caused an elevated GSH:GSSG ratio with a value less than when vitamin E given alone to T4-treated rats. Vitamin E not the curcumin elevates total sperm count and percentage of live sperm impaired by hyperthyroid state. In summary, both vitamin E and curcumin are efficient in protecting testis from oxidative stress generated by T4 mainly in restoring antioxidant enzymes to the level of euthyroid animals up to some extent but vitamin E is more efficient than curcumin.     

Triiodothyronine and melatonin influence antioxidant defense mechanism in a teleost Anabas testudineus (Bloch): in vitro study

The effect of the hormones triiodothyronine (T3) and melatonin on antioxidant defense system was studied in 6-propyl thiouracil (6-PTU)-treated or photoperiod-exposed teleost Anabas testudineus. 6-PTU (2 microg/g) treatment or photoperiod exposure (24 h) increased malondialdehyde (MDA) and conjugated dienes (CD) concentrations, indicating increased lipid peroxidation (LPO) in the experimental conditions. T3 or melatonin (10(-6) M) treatment for 15 min in vitro in PTU-treated fish reversed the activity of superoxide dismutase (SOD), catalase and glutathione content. T3-treated group showed no change in glutathione peroxidase (GPx) activity, whereas melatonin treatment decreased its activity. T3 inhibited glutathione reductase (GR) activity. Photoperiod exposure (physiological pinealotomy) induced a stressful situation in this teleost, as evidenced by LPO products and antioxidant enzyme activities. Melatonin and T3 treatment for 15 min in vitro also reversed the effect of photoperiod on peroxidation products and the SOD and catalase activities. GR activity decreased in photoperiod-exposed group and melatonin and T3 treatment reversed the activities. The antioxidant enzymes responded to the stress situation after 6-PTU treatment and photoperiod exposure by altering their activities. The study suggested an independent effect of T3 and melatonin on antioxidant defence mechanism in different physiological situations in fish.     

The antioxidant status during maturation of reticulocytes to erythrocytes in type 2 diabetics

Free radical-induced lipid peroxidation has been associated with numerous disease processes including diabetes mellitus. The extent of lipid peroxidation (LPO) and antioxidant defense system [i.e., levels of glutathione (GSH), glucose-6-phosphate dehydrogenase (G6PDH), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and catalase (CAT)] were evaluated in reticulocytes and erythrocytes of type 2 diabetic males and age-matched controls. Type 2 diabetics have shown increased lipid peroxidation and decreased levels of GSH, GR, GPx, G6PDH, and GST both in reticulocytes and erythrocytes compared to controls, indicating the presence of oxidative stress and defective antioxidant systems in these patients. CAT activity is found to be enhanced in both the reticulocytes and erythrocytes of diabetics, with a greater percentage enhancement in reticulocytes. The extent of increase in lipid peroxidation is greater in erythrocytes compared to reticulocytes in these patients. Furthermore, the maturation of reticulocytes to erythrocytes resulted in decreased GSH and decreased activities of all antioxidant enzymes (except CAT) both in normals and type 2 diabetes individuals, indicating decreased scavenging capacity as reticulocytes mature to erythrocytes. These maturational alterations are further intensified in type 2 diabetics. The present study reveals that the alterations in lipid peroxidation and antioxidant system lean toward early senescence of erythrocytes in type 2 diabetic patients.     

Rapid regulatory effect of tri-iodothyronine (T3) on antioxidant enzyme activities in a fish Anabas testudineus (Bloch): short-term in vivo and in vitro study

The short-term action of thyroid hormone tri-iodothyronine (T3) was studied in vivo and in vitro on antioxidant enzyme activities in a teleost Anabas testudineus (Bloch). T3 injection in vivo (200 ng) in normal fish decreased the lipid peroxidation products and increased superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activities after 30 min. T3 in vitro (10(-6) M) increased the antioxidant activities of catalase, glutathione reductase (GR), GPx and glutathione level after 15/30 min, except SOD, substantiating in vivo effects in normal fish. The results suggest a rapid regulatory effect of thyroid hormone in vivo and in vitro, in the removal of reactive oxygen species in A testudineus.     

The effect of one year's swimming exercise on oxidant stress and antioxidant capacity in aged rats

The effect of exercise on oxidant stress and on alterations in antioxidant defense in elderly has been investigated extensively. However, the impact of regularly performed long-term physical activity starting from adulthood and prolonged up to the old age is not yet clear. We have investigated the changes in the activities of antioxidant enzymes - superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) - and lipid peroxidation in various tissues of rats which had performed (old-trained) or had not performed (old-control) regular swimming exercise for one year. These animals were compared with young-sedentary rats. Increased lipid peroxidation was observed with ageing in all tissues (heart, liver, kidney, striated muscle) and swimming had no additional effect on this elevation of lipid peroxidation. Heart and striated muscle SOD activites, and striated muscle CAT activity increased as a consequence of ageing, whereas kidney and liver CAT activities, as well as GPx activities in kidney, liver, lung and heart were significantly decreased compared to young controls. Lung and heart SOD, liver CAT activities as well as GPx activities in liver, lung and heart were increased significantly in rats which performed exercise during ageing, compared to the old-control group. These findings suggest that lifelong exercise can improve the antioxidant defense in many tissues without constituting any additional oxidant stress.     

Resveratrol, a red wine polyphenol, attenuates ethanol-induced oxidative stress in rat liver

The involvement of oxidative stress in the pathogenesis of alcoholic diseases in the liver has been repeatedly confirmed. Resveratrol, a natural phytoalexin present in grape skin and red wine possesses a variety of biological activities including antioxidant. This study was conducted to evaluate whether resveratrol has a preventive effect on the main indicators of hepatic oxidative status as an expression of the cellular damage caused by free radicals, and on antioxidant defence mechanism during chronic ethanol treatment. Wistar rats were treated daily with 35% ethanol solution (3 g/kg/day i.p.) during 6 weeks and fed basal diet or basal diet containing 5 g/kg resveratrol. Control rats were treated with i.p. saline and fed basal diet. Experimentally, chronic ethanol administration leads to hepatotoxicity as monitored by the increase in the level of hepatic marker enzymes and the appearance of fatty change, necrosis, fibrosis and inflammation in liver sections. Ethanol also enhanced the formation of MDA in the liver indicating an increase in lipid peroxidation, a major end-point of oxidative damage, and caused drastic alterations in antioxidant defence systems. Particularly the activities of hepatic superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) were found reduced by ethanol treatment while glutathione reductase (GR) activity was unchanged. Dietary supplementation with resveratrol during ethanol treatment inhibited hepatic lipid peroxidation and ameliorated SOD, GPx and CAT activities in the liver. Conclusively, we can suggest that resveratrol could have a beneficial effect in inhibiting the oxidative damage induced by chronic ethanol administration, which was proved by the experiments that we conducted on rats.     

Effects of Bacillus thuringiensis toxin on hepatic lipid peroxidation and free-radical scavengers in rats given alpha-tocopherol or acetylsalicylate

The effect of Dipel (D), a Bacillus thuringiensis-based bioinsecticide, on hepatic antioxidant enzyme activities and lipid peroxidation in rat liver was investigated. Administration of D in a dose of 1 mg/100 g body mass for 4 successive days increased the activities of glutathione peroxidase (GPx), glutathione reductase (GR) and the level of malondialdehyde (MDA) in rat hepatocytes. The activity of superoxide dismutase (SOD) and glutathione (GSH) level were decreased. Administration of D in rats pretreated with alpha-tocopherol (alphaT) or acetylsalicylic acid (ASA) decreased the activities of GPx, GR and MDA levels, while the GSH level was increased compared with rats treated with D alone. The SOD activity was increased in rats pretreated with alphaT before D, but decreased on pretreatment with ASA, compared with rats treated with D alone. The results indicated that D induced oxidative stress in rat liver that has been protected by prior administration of alphaT or ASA.     

Combined effect of alcohol and cigarette smoke on lipid peroxidation and antioxidant status in rats

The effect of long-term administration of alcohol and cigarette smoke independently and both in combination on lipid peroxidation and antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) was studied in liver, kidney, heart and lungs of albino rats. The levels of peroxidation products viz., malondialdehyde, hydroperoxides and conjugated dienes were increased in all the tissues of alcohol administered and smoke-exposed rats. Activities of SOD and CAT were decreased in alcohol-treated and alcohol and smoke combination groups, but increased in smoke-exposed group. Activities of GPx and GST have shown an increase, while concentration of reduced glutathione was found decreased in all the three groups.     

渗透胁迫对黑麦幼苗活性氧和抗氧化酶活性的影响

用20%聚乙二醇(PEG 6000)研究了渗透胁迫对黑麦(Secale cereale L.)幼苗活性氧(reactive oxygen species, ROS)和主要抗氧化酶—— 超氧化物歧化酶(superoxide dismutase, SOD)、过氧化氢酶(catalase, CAT)、抗坏血酸过氧化物酶(ascorbate peroxidase, APX)和谷胱甘肽还原酶(glutathione reductase, GR)活性的影响。结果表明, 与对照相比, PEG处理明显提高了叶子和根中丙二醛(malondialdehyde, MDA)的含量、ROS的水平和以上4种抗氧化酶的活性。渗透胁迫下,叶子和根中MDA和ROS水平变化的规律基本相似, 但抗氧化酶活性在2种器官中表现不完全相同, 叶子中CAT的活性在对照和处理中无显著差异, 但在根中差异明显, 表明叶子中SOD、APX和GR在植物应答渗透胁迫中起重要作用, 而根中这4种抗氧化酶都参与植物对胁迫的反应。GR活性随PEG处理变化幅度显著高于其它抗氧化酶, 表明GR在黑麦应答渗透胁迫中所起作用可能强于其它抗氧化酶。     

Effects of cadmium exposure on lipid peroxidation and the antioxidant system in fourth-instar larvae of Propsilocerus akamusi (Diptera: Chironomidae) under laboratory conditions

Enzymatic antioxidants such as selenium-dependent glutathione peroxidase (GPx), glutathione transferase (GST), glutathione reductase (GR), and superoxide dismutases (SOD), as well as the concentration of hydrogen peroxide (H2O2) and malondialdehyde (MDA, an indicator of lipid peroxidation) were determined to identify which antioxidant enzymes participate in the efficient scavenging of ROS generated upon exposure to high doses of Cd2+ in fourth-instar Propsilocerus akamusi (Tokuna) (Diptera: Chironomidae) larvae after 72-h exposure. A significant increase in MDA levels and a change in GR and GPx activities in the Cd(2+)-treated P. akamusi were observed. The MDA in 25.0 and 50.0 mmol/liter treatments was significantly higher than that of the control dose after 72 h exposure. GPx activity was significantly induced by Cd2+ exposure only in the 50.0-mmol/liter treatment with a 0.59-fold increase in the control. All doses of Cd2+ significantly suppressed GR activity compared with the findings for the control dose, with an inhibited rate up to 0.55-fold in the 25.0 mmol/liter Cd2+ treatment. SOD and GST activities were not altered. The results indicate that Cd2+ can induce oxidative stress as indicated by the changes in lipid peroxidation and antioxidant status. For P. akamusi, an increase in the dose that the threshold needed for defense (namely, MDA level and GPx activity) activation was achieved. From this, organisms can be hypothesized to enable cells to avoid oxidant stress up to a certain extent where damage is again measurable (higher Cd2+ concentration).     

Modulatory effect of Urtica dioica L. (Urticaceae) leaf extract on biotransformation enzyme systems, antioxidant enzymes, lactate dehydrogenase and lipid peroxidation in mice.

The effects of two doses (50 and 100 mg/kg body wt given orally for 14 days) of an ethanol-water (80%-20%) extract of Urtica dioica L. and butylated hydroxyanisole (BHA) were investigated, for phase I and phase II enzymes, antioxidant enzymes, lactate dehydrogenase, lipid peroxidation and sulfhydryl groups in the liver of Swiss albino mice (8-9 weeks old). A modulatory effect of two doses and BHA was also observed for the activities of glutathione S-transferase, DT-diaphorase, superoxide dismutase and catalase in the kidney, lung and forestomach, as compared with the control group. The activities of cytochrome b5 (cyt b5), NADH-cytochrome b5 reductase (cyt b5 R), glutathione S-transferase (GST), DT-diaphorase (DTD), glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD) and catalase (CAT) showed a significant increase in the liver at both dose levels of extract. Both extract-treated showed significantly lower activity of cytochrome P450 (cyt P450), lactate dehydrogenase (LDH), NADPH-cytochrome P450 reductase (cyt P450 R), total sulfhydryl groups (T-SH), nonprotein sulfhydryl groups (NP-SH) and protein-bound sulfhydryl groups (PB-SH). BHA-treated Swiss albino mice showed a notable increase in levels of cyt b5, DTD, T-SH, PB-SH, GPx, GR, and SOD in the liver while, LDH, cyt P450, cyt P450 R, Cyt b5 R, GST, NP-SH, and CAT levels were reduced significantly as compared to control values. The extract was effective in inducing GST, DTD, SOD and CAT activity in the forestomach and SOD and CAT activity in the lung at both dose levels. BHA-treated Swiss albino mice induced DTD, GST and all antioxidative parameters in the kidney, lung and forestomach.     

Thyroid Hormone Influences Antioxidant Defense System in Adult Rat Brain

The objective of the current study was to find out whether thyroid hormone influences antioxidant defense parameters of rat brain. Several oxidative stress and antioxidant defense parameters of mitochondrial (MF) and post-mitochondrial (PMF) fractions of cerebral cortex (CC) of adult rats were compared among euthyroid (control), hypothyroid [6-n-propylthiouracil (PTU)-challenged], and hyperthyroid (T3-treatment to PTU-challenged rats) states. Oxidative stress parameters, such as thiobarbituric acid-reactive substances (TBA-RS) and protein carbonyl content (PC), in MF declined following PTU challenge in comparison to euthyroid rats. On the other hand, when PTU-challenged rats were treated with T3, a significant increase in the level of oxidative stress parameters in MF was recorded. Hydrogen peroxide content of MF as well as PMF of CC was elevated by PTU-challenge and brought to normal level by subsequent treatment of T3. Although mitochondrial glutathione (reduced or oxidized) status did not change following PTU challenge, a significant reduction in oxidized glutathione (GSSG) level was noticed in PMF following the treatment. T3 administration to PTU-challenged rats had no effect on mitochondrial glutathione status. Total and CN-resistant superoxide dismutase (SOD) activities in MF of CC augmented following PTU challenge. CN-resistant SOD activity did not change when PTU-challenged rats were treated with T3. Although CN-sensitive SOD activity of PMF remained unaltered in response to PTU challenge, its activity increased when PTU-challenged rats were treated with T3. Catalase activity in PMF of CC of PTU-challenged rats increased, whereas the activity was decreased when hypothyroid rats were treated with T3. Similarly, total and Se-dependent glutathione peroxidase (GPx) activities of MF increased following PTU challenge and reduced following administration of T3. Se-independent GPx activity of MF and PMF and glutathione reductase activity of PMF decreased following PTU challenge and did not change further when rats were treated with T3. On the other hand, glutathione S-transferase activity of MF and PMF of CC did not change following PTU challenge but decreased below detectable level following T3 treatment. Results of the current investigation suggest that antioxidant defense parameters of adult rat brain are considerably influenced by thyroid states of the body.     

Antioxidant enzymes and lipid peroxides in children with cerebral palsy

Impaired antioxidant mechanisms are unable to inactivate free radicals that may induce a number of pathophysiological processes and result in cell injury. Thus, any abnormality in antioxidant defense systems could affect neurodevelopmental processes and could have an important role in the etiology of cerebral palsy (CP). The plasma levels of lipid peroxidation as plasma levels of malondialdehyde (MDA), activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GR) in plasma and erythrocytes were investigated in 34 CP children and compared with 61 normal controls. SOD, GPx and GR activities were spectrophotometrically assayed. Activities of SOD, GPx and GR in plasma did not differ significantly between CP children and the control group. Activities of erythrocyte GR in the CP patients were significantly lower compared with controls. MDA concentration did not differ statistically between the CP children and healthy subjects. In conclusion our results suggest that increased activities of erythrocyte GPx and decreased erythrocyte GR activities might be due to lesser physical activity of children with CP.     

Induced swimming modified the antioxidant status of gilthead seabream (Sparus aurata)

Swimming has relevant physiological changes in farmed fish, although the potential link between swimming and oxidative stress remains poorly studied. We investigated the effects of different medium-term moderate swimming conditions for 6 h on the antioxidant status of gilthead seabream (Sparus aurata), analyzing the activity of enzymes related to oxidative stress in the liver and skeletal red and white muscle. Forty fish were induced to swim individually with the following conditions: steady low (SL, 0.8 body length (BL)·s⁻¹), steady high (SH, 2.3 BL·s⁻¹), oscillating low (OL, 0.2–0.8 BL·s⁻¹) and oscillating high (OH, 0.8–2.3 BL·s⁻¹) velocities, and a non-exercised group with minimal water flow (MF, < 0.1 BL·s⁻¹). All swimming conditions resulted in lower activities of superoxide dismutase (SOD), glutathione reductase (GR), and glutathione-S-transferase (GST) in the liver compared to the MF group, while steady swimming (SL and SH) led to higher reduced glutathione/oxidized glutathione ratio (GSH/GSSG) compared to the MF condition. Swimming also differently modulated the antioxidant enzyme activities in red and white muscles. The OH condition increased lipid peroxidation (LPO), catalase (CAT) and glutathione peroxidase (GPx) activities in the red muscle, decreasing the GSH/GSSG ratio, whereas the SL condition led to increased GSH. Oscillating swimming conditions (OL and OH) led to lower CAT activity in the white muscle, although GPx activity was increased. The GSH/GSSG ratio in white muscle was increased in all swimming conditions. Liver and skeletal muscle antioxidant status was modulated by exercise, highlighting the importance of adequate swimming conditions to minimize oxidative stress in gilthead seabream.     

Temperature increase results in oxidative stress in goldfish tissues. 2. Antioxidant and associated enzymes

Activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GR), and glucose-6-phophate dehydrogenase (G6PDH) were measured in four tissues of goldfish, Carassius auratus L., over 1-12 h of high temperature (35 degrees C) exposure followed by 4 or 24 h of lower temperature (21 degrees C) recovery. SOD activity was strongly affected by heat shock, increasing 4-fold in brain, liver, and kidney, but was mainly reversed at recovery. In some tissues, activities of SOD, catalase, GPx, and G6PDH decreased significantly after 1 h heat shock exposure suggesting that thermal inactivation possibly occurred, but were renewed at further exposure. In many cases, 4 h of return to the initial temperature decreased enzyme activities. High correlation coefficients between SOD activities and levels of lipid peroxidation products suggest that these products might be involved in up-regulation of antioxidant defense. Several enzymes (SOD, GST, GR) responded to stress in coordinated manner.     

Evaluation of gender-related differences in various oxidative stress enzymes in mice

Oxidative stress caused by redundant free radical, lipid oxygen and peroxide usually results in the pathogenesis of various diseases, which can be alleviated by cellular antioxidant enzymes. According to statistics, there are different incidence rates of some diseases depending on the gender. The present study aimed to investigate potential gender-related differences of antioxidant enzymes in mice. The activities of glutamate-cysteine ligase (GCL), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) in the kidney, brain, lung and heart of both male and female mice were determined. Our results showed that GPx and GCL activities were higher in female kidney and brain than those in male. On the other hand, the activities of SOD were higher in female brain and lung than those in male. Moreover, female kidney appeared to show higher activities of CAT than the male kidney. But the activities of GCL and GPx were higher in male heart than those in female. Taken together, our results demonstrate that there are gender-related differences in the activities of cellular antioxidant enzymes in various important organs in mice. Variations in such enzymes may be the explanation for some gender-related diseases.