Alterations of serum selenium, zinc, copper, and iron concentrations and some related antioxidant enzyme activities in patients with cutaneous leishmaniasis

The aim of this study was to measure the alterations in serum selenium (Se), copper (Cu), zinc (Zn), and iron (Fe) concentrations and their carrier proteins, ceruloplasmin (Cp), transferrin (Tf) albumin, and related antioxidant enzyme activities, erythrocyte Cu-Zn Superoxide dismutase (Cu-Zn SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities in patients with cutaneous leishmaniasis (CL). Erythrocyte Cu-Zn SOD activities, serum Cu concentrations, and Cp levels were found to be significantly higher in the patients group than those of controls. However, GSH-Px and CAT activities and Se, Zn, Fe, and Tf levels were lower in patients than in the control subjects. There were positive important correlation’s between Cu-Zn SOD and Cp, Cu-Zn SOD and Cu, Cp and Cu, GSH-Px and Se, and Fe and CAT in the patients group. Our results showed that serum essential trace elements Se, Zn, Cu, and Fe concentrations and their related enzymes Cu-Zn SOD, GSH-Px, and CAT activities change in CL patients. The changes may be a part of defense strategies of organism and are induced by the hormonelike substances.     

Plasma and erythrocytes antioxidant status and trace element levels in proteinuric patients with moderate glomerular function.

The objective of the study was to investigate the effect of moderate glomerular dysfunction on oxidative stress. We determined the plasma and erythrocyte malondialdehyde (MDA) levels, as a marker of lipid peroxidation, erythrocyte glutathione (GSH) levels and activities of GSH-Px, GSH Red and SOD as an antioxidant enzymes, and plasma trace element levels containing Fe, Cu and Zn in twenty proteinuric patients (6.8 +/- 5.1 g/day) with moderate glomerular function and in 20 anemic control subjects. We found that the erythrocyte and plasma MDA levels and erythrocyte GSH-Px activities were significantly higher (p < 0.001, p < 0.001, p < 0.001, respectively) and the erythrocyte GSH levels and activities of GSH-Red and SOD activities were significantly lower (p < 0.001, p < 0.001, p < 0.001, respectively) in the patients than in the anemic subjects. Plasma Fe and Zn levels were not to be found significantly different in the patients compared to the anemic subjects. But plasma Cu levels were significantly higher in the patients (p < 0.05) when compared with the levels of anemic subjects. This study was concluded that cellular antioxidant activity decreases in proteinuric patients with moderate glomerular function. This may increase lipid peroxidation reactions by causing oxidative stress in erythrocyte membranes.     

Defective antioxidant defense system in patients with a human leptin gene mutation.

Antioxidant defense system prevents the organism from the detrimental effects of free radicals via scavenging or inhibiting their formation. Changes in the antioxidant defense mechanisms and alterations of several essential trace elements in both plasma and various tissues of ob/ob mice have been reported previously. Recent finding of the restoration of the defective antioxidant enzyme activity after leptin treatment in ob/ob mice suggests a putative role of leptin in modulation of antioxidant enzyme activity. Therefore, the aim of this study was to investigate whether antioxidant enzymes and trace elements could also be altered in patients with leptin gene mutation. Seven patients (five men and two women, two of them are homozygous and 5 are heterozygous) with leptin gene mutation and 31 healthy, sex- and age-matched and non-related to the patients (24 male and 9 female), control volunteers were enrolled in the study. Plasma and erythrocyte glutathione peroxidase (GSH-Px) and erythrocyte copper-zinc superoxide dismutase (CuZn-SOD) activities were measured spectrophotometrically. Plasma selenium (Se), manganese (Mn), zinc (Zn), copper (Cu), and iron (Fe) levels were measured by atomic absorption spectrophotometry. Mean Cu and Fe levels in patients were not significantly different than those in controls whereas mean Se, Zn and Mn levels were significantly lower in patients than those of controls (P=0.007, P=0.001, and P=0.001, respectively). Erythrocyte GSH-Px (39%), plasma GSH-Px (24%) and erythrocyte CuZn-SOD activities (32%) were significantly lower than those of the control group (P=0.001, P=0.002, P=0.001, respectively). In conclusion, our results demonstrate that the activity of antioxidant enzymes and plasma levels of Se, Zn and Mn levels were decreased in both homozygous and heterozygous subjects with leptin gene mutation. We suggest that both leptin and trace elements might be involved in the modulation of antioxidant defense system.     

Antioxidative metabolism in down syndrome

Down syndrome is the most common cause of mental retardation, affecting 1 in 700–800 liveborn infants. Although numerous biochemical abnormalities accompanying the syndrome have not yet been completely clarified, the antioxidant defense system enzymes have shown to be altered due to increased gene dosage on chromosome 21 and overproduction of superoxide dismutase (SOD-1 or Cu/Zn SOD). The purpose of this study was to investigate the activities of SOD-1 and glutathione peroxidase (GSH-Px) enzymes and the levels of their cofactors zinc (Zn), copper (Cu) and selenium (Se) in plasma of 20 Down syndrome patients. In comparison with age and sex-matched controls (n=15), plasma GSH-Px, SOD, and Cu levels were significantly decreased in the patient group, but Zn and Se concentrations remained unchanged. This study was presented as a poster in 29th Annual Meeting of European Society of Human Genetics held in Genoa in May, 1997.     

Alterations of plasma magnesium,copper, zinc,iron and selenium concentrations and some related erythrocyte antioxidant enzyme activities in patients with Alzheimer’s disease

The aim of the present study is to evaluate the status of plasma essential trace elements magnesium (Mg), copper (Cu), zinc (Zn), iron (Fe) and selenium (Se) concentrations and their some related antioxidant enzyme activities, erythrocyte glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) activities in patients with Alzheimer’s disease (AD). Fifty patients with AD and fifty healthy control subjects were included in this study. Plasma Cu and Zn concentrations by atomic absorption spectrometry (AAS), plasma Mg and Fe concentrations by spectrophotometric methods and plasma Se concentrations by graphite furnace AAS were determined. Erythrocyte GPx, SOD and CAT activities were measured by spectrophotometric methods. Plasma Mg, Cu, Zn, Fe and Se levels and erythrocyte GPx, SOD and CAT activities were found to be significantly lower in patients with AD compared with controls. These results suggest that alterations in essential trace elements and their related enzymes may play a role in the etiopathogenesis of AD. Also, there is a defect in the antioxidant defense system, which may lead to oxidative damage in patients with AD. The changes in antioxidant enzyme activities may be secondary to the alterations in their cofactor concentrations.     

Effects of fluoride on hepatic antioxidant system and transcription of Cu/Zn SOD gene in young pigs

Thirty-two barrows (Duroc x Landrace x Yorkshire) were randomly divided into four groups, each of which included eight pigs. The groups received the same basal diet supplemented with 0, 100, 250 and 400mg/kg fluoride, respectively. The malondialdehyde (MDA) and glutathione (GSH) levels, antioxidant enzymes activities and zinc/copper superoxide dismutase (Cu/Zn SOD) mRNA content in the liver were determined to evaluate the fluoride hepatic intoxication. Results showed the increased lipid peroxides (LPO) level and the reduced GSH content, along with a concomitant decrease in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px). Moreover, the level of hepatic Cu/Zn SOD mRNA was also significantly reduced. We suggest the mechanism of fluoride injuring the liver as follows: fluoride causes a decrease in Cu/Zn SOD mRNA and the reduced activities of antioxidant enzymes, leads to the declined ability of scavenging free radicals with excessive production of LPO, which seriously damages the hepatic structure and function.     

Effects of halothane, enflurane, and isoflurane on plasma and erythrocyte antioxidant enzymes and trace elements

Alterations of the normal redox balance in mammals might be attributed to increases of plasma free-radical concentrations and/or a disruption of the protective mechanisms. These conditions lead to damage to cellular structure by the mechanism of lipoperoxidation, particularly in the liver, kidney, and central nervous system. In this study, the effect of general anesthesia on the oxidative metabolism of human plasma and erythrocytes was investigated. Forty-five patients undergoing anesthesia by using halothane, enflurane, or isoflurane were included in this study. Blood samples were taken preoperatively, the first hour, the first day, and the third day after the operation. Superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) enzyme activities and trace elements such as cofactor copper (Cu), zinc (Zn) and selenium (Se) levels were measured in plasma and red blood cells. Our results showed that halothane and enflurane administration increased the plasma GSH-Px activity and reduced zinc levels. In addition, they lowered SOD and GSH-Px activities and trace element levels on erythrocytes. Isoflurane had no effect on plasma antioxidant enzymes, but, similar to the other, isoflurane decreased the plasma zinc levels, erythrocyte SOD and GSH-Px activities and trace element levels. Gülhane Military Medical Academy     

The effect of natural dicarbonyls on activity of antioxidant enzymes in vitro and in vivo

Natural dicarbonyls, which may be accumulated during oxidative stress in atherosclerosis (e.g. malondialdehyde) or carbonyl stress in diabetes mellitus (glyoxal and methylglyoxal) effectively inhibited activities of commercial preparations of the antioxidant enzymes: Cu,Zn-superoxide dismutase (Cu,Zn-SOD) and Se-contained glutathione peroxidase from human and bovine erythrocytes, and also rat liver glutathione-S-transferase. After incubation of human erythrocytes with 10 mM of each investigated dicarbonyls the decrease of intracellular Cu,Zn-SOD was observed. The decreased activity of erythrocyte Cu,Zn-SOD was also detected in patients with diabetes mellitus type 2 with carbohydrate metabolism impairments but effective sugar-lowered therapy was accompanied by the increase of this enzyme activity. The increase of erythrocytes Cu,Zn-SOD activity in diabetic patients treated with metformin (which may utilize methylgly-oxal) was higher than in erythrocytes of diabetic patients subjected to traditional therapy.     

The relation between selenium, zinc and copper concentration and the trace element dependent antioxidative status.

An imbalance in the antioxidative system was connected with the development of a number of pathological processes. In order to receive values of a healthy group and to evaluate pathological changes of the trace element dependent antioxidative status in future, we investigated 99 healthy volunteers (45 male and 54 female, mean age 37.4 +/- 11.7 years). We determined the concentrations of Se, Cu and Zn, the concentrations of malondialdehyde (MDA) and the activities of the Se dependent glutathione peroxidase (GSH-Px) and the Zn/Cu dependent superoxide dismutase (SOD). The plasma concentrations (mean +/- SD) for Se, Cu and Zn were 0.84 +/- 0.10 micromol/l, 15.6 +/- 2.78 micromol/l and 12.6 +/- 1.80 micromol/l, resp., and for non protein-bound and protein bound MDA 0.27 +/- 0.07 micromol/l and 1.11 +/- 0.25 micromol/l, resp. The activity of GSH-Px in plasma and erythrocytes was 130 +/- 20.8 U/l and 19.8 +/- 4.18 U/mg Hb, resp. and of SOD in erythrocytes 3,159 +/- 847.2 U/g Hb. In plasma positive correlations have been found between Se concentrations and GSH-Px activities (p < 0.002, r = 0.31) and between GSH-Px activities and concentrations of non protein-bound MDA (p = 0.004, r = 0.28). A negative correlation has been observed between GSH-Px activities in plasma and in erythrocytes. The higher the concentrations of Cu in erythrocytes, the higher were the activities of SOD (p = 0.03, r = 0.22) and GSH-Px in erythrocytes (r = 0.26, p = 0.01), while an increasing activity of GSH-Px in these cells correlated with a decreasing concentration of non protein-bound MDA (r = -0,31, p = 0.002). An increase in BMI was connected with an increase in protein-bound MDA and a decrease in GSH-Px activities in pLasma (p = 0.002 and r = 0.23). As the results demonstrate, Se and Cu concentrations in erythrocytes can improve the trace element dependent antioxidative status.     

Lipid peroxidation and scavenging enzyme levels in the liver of streptozotocin-induced diabetic rats

In this study, alterations in the liver antioxidant enzymes status and lipid peroxidation in short-term (8-weeks) and long-term (24-weeks) diabetic rats were examined. Glutathione peroxidase (GSH-Px) activity and malondialdehyde (MDA) levels were significantly increased, but superoxide dismutase (SOD) activity was significantly reduced in 8-weeks diabetic rats, compared to control. Catalase (CAT) activity, however, was found unchanged. In 24-weeks diabetic rats, while GSH-Px activity was unchanged, but SOD and CAT activities and MDA levels were significantly increased, compared to control. These results suggest that diabetes-induced alterations in tissue antioxidant system may reflect a generalized increase in tissue oxidative stress. It can be concluded that lipid peroxidation and antioxidant enzyme levels are elevated in diabetic condition. Hence, diabetes mellitus, if left untreated, may increase degenerative processes due to accumulation of oxidative free radicals.     

Protective effect of caffeic acid phenethyl ester (CAPE) on lipid peroxidation and antioxidant enzymes in diabetic rat liver

The aim of this study was to examine the effect of caffeic acid phenethyl ester (CAPE) on lipid peroxidation (LPO) and the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in the liver of streptozotocin (STZ)-induced diabetic rats. Twenty-seven rats were randomly divided into three groups: group I, control non-diabetic rats (n = 9); group II, STZ-induced, untreated diabetic rats (n = 8); group III, STZ-induced, CAPE-treated diabetic rats (n = 10), which were intraperitoneally injected with CAPE (10 microM kg(-1) day(-1)) after 3 days followed by STZ treatment. The liver was excised after 8 weeks of CAPE treatment, the levels of malondialdehyde (MDA) and the activities of SOD, CAT, and GSH-Px in the hepatic tissues of all groups were analyzed. In the untreated diabetic rats, MDA markedly increased in the hepatic tissue compared with the control rats (p < 0.0001). However, MDA levels were reduced to the control level by CAPE. The activities of SOD, CAT, and GSH-Px in the untreated diabetic group were higher than that in the control group (p < 0.0001). The activities of SOD and GSH-Px in the CAPE-treated diabetic group were higher than that in the control group (respectively, p < 0.0001, p < 0.035). There were no significant differences in the activity of CAT between the rats of CAPE-treated diabetic and control groups. Rats in the CAPE-treated diabetic group had reduced activities of SOD and CAT in comparison with the rats of untreated diabetic group (p < 0.0001). There were no significant differences in the activity of GSH-Px between the rats of untreated diabetic and CAPE-treated groups. It is likely that STZ-induced diabetes caused liver damage. In addition, LPO may be one of the molecular mechanisms involved in STZ-induced diabetic damage. CAPE can reduce LPO caused by STZ-induced diabetes.     

Effects of statins on oxidative stress

Free oxygen radicals and insufficient antioxidant enzymes have been implicated in the pathogenesis of hypercholesterolemia (HC). Trace elements function as cofactors in antioxidant enzymes. Antioxidant system and trace elements were investigated in many different studies including HC, but these subjects have not been investigated as a whole in these patients. The aim of the present study was to investigate the antioxidative system and trace elements in hypercholesterolemic patients given fluvastatin therapy. We examined malondialdehyde (MDA), copper zinc-superoxide dismutase (CuZn-SOD), and glutathione peroxidase (GSH-Px) activities together with copper (Cu), iron (Fe), and zinc (Zn) levels in erythrocytes of 35 patients with HC and 27 healthy control subjects. It was found that in patients with HC, erythrocyte MDA was significantly higher than those of controls and erythrocyte CuZn-SOD and GSH-Px activities were significantly lower in patients with HC. Erythrocyte iron levels were significantly higher than those of controls, and erythrocyte copper and zinc levels were significantly lower in patients with HC. Plasma lipid levels and the oxidative state were analyzed in statin-treatment groups given fluvastatin therapy before and after a 3-mo treatment period. In conclusion, we found that fluvastatin has significant antioxidant properties and these effects might be very important in managing dyslipidemia by improving endothelial function.     

Whole blood glutathione peroxidase and erythrocyte superoxide dismutase activities, serum trace elements (Se, Cu, Zn) and cardiovascular risk factors in subjects from the city of Ponta Delgada, Island of San Miguel, The Azores Archipelago, Portugal

Activities of whole blood glutathione peroxidase (GSH-Px) and erythrocyte superoxide dismutase (SOD) and serum levels of selenium (Se), copper (Cu) and zinc (Zn) were measured in 118 apparently healthy subjects aged 20-60 years from the city of Ponta Delgada, Island of San Miguel, The Azores Archipelago, Portugal. Data were analysed by age/gender, lipid profile and blood pressure as cardiovascular risk factors searching for their relevance when assessing reference values for antioxidant biomarkers. GSH-Px was in the same range, but SOD was significantly lower than in other Portuguese populations. Neither activity differed with gender. GSH-Px activity increased with age, namely in normolipidemic men versus the hyperlipidemic group in which a decrease was observed. This suggests a progressive impairment of GSH-Px with age caused by an enhanced production of oxidant species in hyperlipidemia. GSH-Px was 30% lower in male hypertensives versus normotensives. SOD activity did not relate to age or blood pressure but was 17% higher in the hyperlipidemic men versus the normolipidemic group, suggesting a better antioxidant protection by SOD than by GSH-Px in hyperlipidemia and hypertension. Se was higher in men versus women, particularly in the older subjects, and partly related to hyperlipidemia. Zn levels showed a similar dependency on gender, not related to age or lipid profile. Cu levels were much higher in women than in men in all age or lipid profile classes and decreased in hyperlipidemia. They were lowered with age in both genders, particularly in normolipidemic women. The present research therefore suggests that hyperlipidemia and hypertension do affect antioxidant status and should be considered when assessing antioxidant biomarkers in blood.     

Whole blood glutathione peroxidase and erythrocyte superoxide dismutase activities,serum trace elements (Se,Cu, Zn) and cardiovascular risk factors in subjects from the city of Ponta Delgada,Island of San Miguel,The Azores Archipelago,Portugal

Activities of whole blood glutathione peroxidase (GSH-Px) and erythrocyte superoxide dismutase (SOD) and serum levels of selenium (Se), copper (Cu) and zinc (Zn) were measured in 118 apparently healthy subjects aged 20–60 years from the city of Ponta Delgada, Island of San Miguel, The Azores Archipelago, Portugal. Data were analysed by age/gender, lipid profile and blood pressure as cardiovascular risk factors searching for their relevance when assessing reference values for antioxidant biomarkers. GSH-Px was in the same range, but SOD was significantly lower than in other Portuguese populations. Neither activity differed with gender. GSH-Px activity increased with age, namely in normolipidemic men versus the hyperlipidemic group in which a decrease was observed. This suggests a progressive impairment of GSH-Px with age caused by an enhanced production of oxidant species in hyperlipidemia. GSH-Px was 30% lower in male hypertensives versus normotensives. SOD activity did not relate to age or blood pressure but was 17% higher in the hyperlipidemic men versus the normolipidemic group, suggesting a better antioxidant protection by SOD than by GSH-Px in hyperlipidemia and hypertension. Se was higher in men versus women, particularly in the older subjects, and partly related to hyperlipidemia. Zn levels showed a similar dependency on gender, not related to age or lipid profile. Cu levels were much higher in women than in men in all age or lipid profile classes and decreased in hyperlipidemia. They were lowered with age in both genders, particularly in normolipidemic women. The present research therefore suggests that hyperlipidemia and hypertension do affect antioxidant status and should be considered when assessing antioxidant biomarkers in blood.     

Effect of dietary caffeine and zinc on the activity of antioxidant enzymes,zinc, and copper concentration of the heart and liver in fast-growing rats

The purpose of this study was to determine the relationship between concentrations of Zn and Cu and the activities of superoxide dismutase and glutathione peroxidase in the heart and liver of young rat pups whose dams were fed a diet supplemented with caffeine and/or Zn. Four groups of dams with their newborn pups were fed one of the following diets for 22 d: 20% protein basal diet; the basal diet supplemented with caffeine (2 mg/100 body wt); the basal diet supplemented with Zn (300 mg/kg diet); or the basal diet supplemented with caffeine plus Zn. The Cu levels in the livers of the pups were decreased by maternal intake of the caffeine and Zn diet. The maternal intake of the caffeine diet increased Mn-superoxide dismutase (MnSOD) activity and Cu, Zn-superoxide dismutase (CUZnSOD) in the heart of the pups. On the other hand, the activity of Cu,ZnSOD was significantly reduced in the liver of pups whose dams consumed a caffeine, Zn, or caffeine plus Zn diet. Cu, ZnSOD activity in the liver of the pups seems to be correlated with Cu levels in the tissue. Selenium-dependent glutathione peroxidase (GSH-Px) activities in the heart and liver showed no difference among the groups. The effect of dietary caffeine and/or Zn on the activity of antioxidant enzymes in the heart and liver were different in young rats. The activities of these enzymes in the heart were lower than in the liver of 22-d-old rats. Our experiments indicate that the heart has limited defenses against the toxic effects of peroxides when compared to the liver.     

The effects of some antioxidant vitamin- and trace element-supplemented diets on activities of SOD, CAT, GSH-Px and LPO levels in chicken tissues

The effect of diets containing antioxidant vitamins and trace elements on chicken tissue activities of SOD, CAT, GSH-Px and of LPO levels was investigated. Chickens, 45 weeks of age were divided into six groups: control group, Cu group (13.2 mg Cu kg(-1) diet); Se group (0.07 mg Se kg(-l) diet); vitamin E group (70 mg DL-alpha-tocopherol acetate kg(-1) diet) and a constant level vitamin C, 200 mg kg(-1) diet); vitamin A group (240 mg retinol acetate kg(-1) diet) and vitamin C group (500 mg ascorbic acid kg(-1) diet). Significant variation of these antioxidant enzyme activities and LPO levels according to gender was demonstrated statistically. In the Cu group, CuZnSOD activity in the liver, erythrocyte, kidney and heart significantly increased by 75, 40, 12, 12% respectively (P<0.05). MnSOD activity in the heart, liver, kidney and brain of the vitamin C and in the heart of Cu group were found to be increased by approximately 15%, while in liver tissue of the Cu group it was reduced by 19% (P<0.05). GSH-Px activities in the Se, vitamin E and C groups were significantly increased, conversely LPO levels decreased (P<0.001). CAT activities in the liver and heart of the vitamin C group were significantly decreased (by 32%), but in kidney tissue only that of the Cu group was increased from 30.2 +/- 4.767 to 144.49 +/- 6.93 U mg(-1) P<0.001. The resistance to stress of the vitamin E and C groups, which had significantly increased activities of antioxidant enzymes and decreased lipid peroxide levels, were determined in 60% moisture medium at 45 degrees C.     

Nitric oxide levels and antioxidant enzyme activities in jaundices of premature infants

Free radicals are effective in the genesis of several diseases in the neonatal period. This study aimed to show the relationship between serum bilirubin levels and plasma nitric oxide and the activity of enzymes in the erythrocyte such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in premature infants. In the study, 20 premature infants with newborn jaundice were included and the control group was formed by 15 premature infants without jaundice. Venous blood samples were taken from all neonates in the study and control groups on the first day of hospitalization. Plasma nitric oxide levels and activities of SOD, GSH-Px and CAT enzymes in the erythrocytes were investigated in these samples. Plasma nitric oxide and serum bilirubin levels were found to be significantly higher in the study group (47.4 +/- 7.25 micromol l(-1), 18.41 +/- 3.28 mg dl(-1), respectively) than those in the control group (33.46 +/- 6.43 micromol l(-1), 4.35 +/- 0.60 mg dl(-1), respectively; p < 0.001). In addition, erythrocyte SOD, GSH-Px and CAT enzyme activities (724 +/- 78.61, 673 +/- 90.5, 63 +/- 12.8 U g(-1) Hb, respectively) were found to be significantly lower in the study group than those in the control group (1208 +/- 129.04, 1097.6 +/- 75.8, 99.06 +/- 12.4 U g(-1) Hb, respectively, p < 0.001). It was concluded that in the aetiology of hyperbilirubinemia, neonatal erythrocytes and nitric oxide reactions are affected differently and that erythrocyte haemolysis caused as a result of these effects may play a role in the aetiopathogenesis of unconjugated hyperbilirubinemia. Haemolysis may also be seen because of the inadequacy of the protection by erythrocytes against the cytotoxic effects of free radicals resulting from the lack of antioxidant enzymes in these cells.     

Effects of Lead on Hepatic Antioxidant Status and Transcription of Superoxide Dismutase Gene in Pigs

Ninety-six castrated boars (Duroc x Landrace x Yorkshire) were randomly divided into four groups, each of which was replicated three times with eight pigs. The groups received the same basal diet supplemented with 0, 5, 10, and 20 mg/kg lead, respectively. The malondialdehyde and glutathione levels, antioxidant enzymes activities, and zinc/copper superoxide dismutase (Zn/Cu SOD) mRNA content in the liver were determined to evaluate the lead hepatic intoxication caused by the lead. Results showed the increased lipid peroxides level and the reduced glutathione content, along with a concomitant decrease in the activities of superoxide dismutase, catalase, and glutathione peroxidase. Moreover, the level of hepatic Zn/Cu SOD mRNA was also significantly reduced. We suggest potential mechanism for lead intoxication in liver as follows: lead causes parallel decrease in Zn/Cu SOD mRNA and activities of antioxidant enzymes, leading to the declined ability of scavenging free radicals with excessive production of lipid peroxides, which seriously damages the hepatic structure and function.     

Age-related changes in antioxidant enzyme activities and lipid peroxidation in lungs of control and sulfur dioxide exposed rats

Antioxidant defenses within the lung are pivotal in preventing damage from oxidative toxicants. There have also been several reports with conflicting results on the antioxidant system during aging. In this study, we attempted to investigate age-related alterations in both antioxidant enzyme activities and thiobarbituric acid-reactive substances (TBARS), a product of lipid peroxidation, in the whole lung of control and sulfur dioxide (SO₂) exposed rats of different age groups (3-, 12-, and 24-months-old). Swiss-Albino Male rats were exposed to 10 ppm SO₂ 1 hr/day, 7 days/week for 6 weeks. The antioxidant enzymes examined include Cu,Zn-superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione S-transferase (GST). A mixed pattern of age-associated alterations in antioxidant activities was observed. SOD, GSH-Px and GST activities were increased with age, but CAT activity was decreased. Lung SOD, GSH-Px and GST activities were also increased in response to SO₂. The level of TBARS was increased with age. SO₂ exposure stimulated lipid peroxide formation in the lung as indicated by an increase in the level of TBARS. These findings suggest that both aging and SO₂ exposure may impose an oxidative stress to the body. We conclude that the increase in the activities of the antioxidant enzymes of the lung during aging, could be interpreted as a positive feedback mechanism in response to rising lipid peroxidation.