Suitability of copper chloride as a reaction terminator for superoxide dismutase activity assay

Does taurolidine have any effect on liver regeneration and oxidation in the experimental hepatectomy model?

Objective: Taurolidine is a bicyclic molecule produced by the natural amino acid taurine. Antibacterial, antiendotoxic and cytoprotective effects of taurolidine have been shown experimentally. Data on the effects of taurolidine on oxidative stress and hepatic regeneration are limited. The aim of the study was to evaluate the effect of taurolidine on hepatic regeneration and oxidative stress in rats undergoing partial hepatectomy.

Material and Methods: Forty adult, male Wistar Albino rats were randomly divided into four equal groups: sham (S) group (n= 10), post-sham opera- tion taurolidine administered (ST) group (n= 10), partial hepatectomy (H) group (n= 10) and post-partial hepatectomy taurolidine administered (HT) group (n= 10). 100 mg/kg/day taurolidine was administered for seven days. Blood and liver tissue samples were collected on postoperative day seven. Liver tissue malondialdehyde, glutathione and Cu-Zn superoxide dismutase activity (SOD) were measured to assess oxidative stress. Binuclear hepato- cyte and Ki-67 antigen levels were measured to evaluate hepatic regeneration.

Results: There was no difference between the groups for malondialdehyde, Cu-Zn superoxide dismutase and glutathione levels (p> 0.05). Binuclear nuclei levels were comparable between the H and HT groups (p= 0.06), while taurolidine decreased binuclear hepatocyte levels in the sham operated groups (p= 0.02). Taurolidine application decreased Ki-67 levels after partial hepatectomy (p= 0.001).

Conclusion: Taurolidine may cause anti-regenerative effects after partial hepatectomy without causing oxidative damage.

Selenium Supplementation May Decrease Thyroid Peroxidase Antibody Titer via Reducing Oxidative Stress in Euthyroid Patients with Autoimmune Thyroiditis

OBJECTIVE

Selenium, as an antioxidant, has been implicated in the development of autoimmune thyroiditis (AIT). Many studies showed selenium supplementation could decrease thyroid autoantibodies in patients with AIT. However, the underlying mechanisms have not been well determined. Therefore, we performed a clinical study to investigate the possible mechanism of beneficial effects of selenium treatment on AIT patients.

METHODS

Forty euthyroid patients with AIT were randomized into two groups. Group I was treated with 200 μg/day selenium supplementation, and group II received a placebo over a 3-month period. Thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), antithyroglobulin antibody (TgAb), malondialdehyde (MDA), total antioxidant capacity (TAC), and superoxide dismutase (SOD) were measured before and 3 months after treatments. Additionally, twenty healthy volunteers also served as a control group for the evaluation of such parameters in basic condition.

RESULTS

Totally, 32 patients (group I, n = 18; group II, n = 14) completed the clinical study and were incorporated into the statistics. MDA level was higher and SOD activity and TAC were lower in patients compared to healthy individuals. After 3 months, TPOAb titer significantly decreased within group I (P < 0.001) but did not change within group II (P=0.001). There were also no statistically significant changes in TSH and TgAb titers within the two groups (all P > 0.05). Additionally, decreased MDA level (from 6.8 ± 1.3 nmol/ml to 4.9 ± 0.7 nmol/ml; P < 0.001) and increased TAC (from 10.0 ± 1.9 mmol/l to 12.9 ± 3.1 mmol/l; P=0.003) and SOD activity (from 72.3 ± 10.3 U/ml to 84.3 ± 13.2 U/ml; P=0.007) were simultaneously observed after 3 months' selenium treatment. Moreover, there was a negative correlation between TAC and TgAb/TPOAb and a positive correlation between MDA and TgAb/TPOAb in AIT patients.

CONCLUSIONS

Our findings support the hypothesis that selenium treatment could decrease TPOAb titer via enforcing the defense against oxidative stress in euthyroid patients with AIT, which may be a potential underlying mechanism.

Hormone replacement therapy: relation to homocysteine and prooxidant-antioxidant status in healthy postmenopausal women

OBJECTIVES

Studies have consistently shown a lower cardiovascular risk in women who received postmenopausal hormone replacement therapy (HRT).

DESIGN AND METHODS

In this study, the effects of HRT were investigated on plasma total homocysteine (tHcy) and the oxidant-antioxidant status in postmenopausal women. 35 of postmenopausal receiving (2 mg estrodiol valerate + 1 mg cyproterone acetate) HRT group, the remaining 25 received orally placebo (NHRT group).

RESULTS

There was no significant change in plasma tHcy levels between HRT and NHRT groups. Malondialdehyde (MDA) and total thiol (t-SH) correlated significantly with tHcy (0.388 and 0.478, respectively) content, and there was a significant negative correlation between E2 level and glutathione transferase (GST) activity (-0.425) in HRT group. Superoxide dismutase (SOD) and HDL-C correlated significantly with t-SH level (0.339 and 0.336, respectively) in plasma after HRT.

CONCLUSION

Our results show that HRT is beneficial in the protection against oxidative damage, and prevents atherosclerotic complications.

A polysaccharide-peptide complex from abalone mushroom (Pleurotus abalonus) fruiting bodies increases activities and gene expression of antioxidant enzymes and reduces lipid peroxidation in senescence-accelerated mice

The antioxidant effects of a polysaccharide-peptide complex (F22) from mushroom (Pleurotus abalonus)-fruiting bodies were studied. The activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in the liver, kidney, and brain of senescence-accelerated mice showed a marked increase after treatment with the polysaccharide-peptide complex. Concurrently, the gene expression levels of SOD, CAT, and GPx, as determined with real-time polymerase chain reaction, were up-regulated in the liver, kidney, and brain, whereas the MDA content in these organs declined. The maximal lifespan of the mice was prolonged.

Determination of oxidative stress in thyroid tissue and plasma of patients with Graves' disease

BACKGROUND

The aim of our study was to evaluate the oxidant/antioxidant status of thyroid tissue in Graves' disease (GD) patients and to compare the results of GD thyroid tissue with plasma of patients and healthy controls.

METHODS

We studied 25 consecutive patients with GD hyperthyroidism who underwent surgical treatment. The patients were divided into groups according to the duration of antithyroid drug treatment, the type of antithyroid drugs used, the presence of ophthalmopathy, and recurrence after a complete course of antithyroid drugs. Thiobarbituric acid-reacting substances (TBARS), glutathione peroxidase (GPx) activity, superoxide dismutase (SOD) activity, and total thiol (t-SH) content of tissue and plasma samples were determined.

RESULTS

TBARS concentrations were found to be significantly increased in GD patients' plasma compared with controls' plasma (0.1+/-0.02 nmol/mg protein vs. 0.062+/-0.01 nmol/mg protein). Significantly decreased t-SH concentrations were measured in GD patients' plasma compared with controls (8.26+/-1.9 nmol/mg protein vs. 13.03+/-3.3 nmol/mg protein). Tissue TBARS, t-SH, GPx, and SOD measurements in GD patients indicated significantly increased concentrations compared with the plasma levels of patients. Patients with shorter treatment duration before the operation had significantly increased plasma and tissue TBARS and decreased plasma and tissue t-SH concentrations. Patients on propylthiouracil treatment had significantly lower plasma and tissue concentrations of TBARS than patients on methimazole. Patients with recurrence had significantly higher plasma and tissue TBARS and lower plasma and tissue t-SH concentrations than patients treated for the first time.

CONCLUSIONS

In euthyroid GD patients on antithyroid drugs, increased oxidative stress and a compensatory increase in the antioxidant defense system are more prominent in thyroid tissue than in plasma. Patients who relapsed had markers indicating increased oxidative stress. Thus, ongoing autoimmunity may contribute to increased oxidative stress in GD patients, even in the euthyroid state.

Rose (Rosa rugosa)-flower extract increases the activities of antioxidant enzymes and their gene expression and reduces lipid peroxidation

The effects of rose-flower extract on antioxidant enzymes were studied. The activities of catalase (CAT) and glutathione peroxidase (GPx) in 9-month-old senescence-accelerated mice (SAM mice) were lower than those in 6-month-old SAM mice. Therefore, 9-month-old SAM mice were the most appropriate targets for treatment with the rose-flower extract. The activities of CAT and GPx in SAM mice treated with rose-flower extract showed a marked increase in whole blood and liver. At the same time, the gene-expression level of CAT and GPx was upregulated in the liver, while malondialdehyde content in liver and brain decreased. Male SAM mice were more sensitive than female SAM mice. The mean and the longest lifespan of SAM mice were longer after treatment with rose-flower extract.Key word: anti-aging, CAT, GPx, lipid peroxidation.

Changes of oxidative stress in various tissues by long-term administration of vitamin E in hypercholesterolemic rats

BACKGROUND

Free radical-mediated oxidative stress has been implicated in the genesis and progression of atherosclerosis.

METHODS

The lipid peroxides and antioxidant status of various tissues were investigated in hypercholesterolemic rats and the effect of vitamin E supplementation on defense systems.

RESULTS

Cholesterol-feeding caused a significant increase in the lipid peroxide concentrations of plasma, erythrocytes, liver and brain. In addition, a significant decrease in glutathione (GSH) content, glutathione peroxidase (GSH-Px) and glutathione transferase (GSH-ST) activities were found in erythrocytes and liver but superoxide dismutase (SOD) activity remained unchanged in these tissues in comparison to the control group. Vitamin E supplementation to hypercholesterolemic rats induced a significantly decrease in lipid peroxide concentrations and a significant increase in the GSH content, GSH-Px and GSH-ST activities in erythrocytes and liver.

CONCLUSIONS

Long-term administration of vitamin E may play an important role in suppressing oxidative stress, and thus, may be useful for the prevention and/or early treatment of hypercholesterolemia.

Oxidant-antioxidant profiles of platelet rich plasma in smokers

Cigarette smoke is a major risk factor for both coronary heart disease and peripheral vascular disease and has been reported to contain many oxidizing agents that lead to generation of free radicals. In this study, we investigated the levels of lipid peroxides (LPO) and antioxidant vitamins (C and E), total thiol content (t-SH), the activities of superoxide dismutase (SOD), glutathione S-transferase (GST) and glutathione peroxidase (GPx) in the platelet-rich plasma (PRP) and plasma of 50 smokers and 30 non-smokers. Total cholesterol (TC), low density-cholesterol (LDL-C), triglyceride (TG) and phospholipid (PL) levels of the plasma were significantly higher (p < 0.001) and high density-cholesterol (HDL-C) levels were significantly lower in smokers (p < 0.001) when compared with non-smokers. In plasma and PRP, LPO levels, GST and SOD activities were found to be increased (p < 0.001) in smokers, whereas GPx activity, vitamin C levels and t-SH content were found to be decreased. On the other hand, the levels of vitamin E was unchanged in plasma and PRP. The relationships between plasma levels of lipids, LPO and antioxidant systems were also investigated in both groups. A strong positive correlation was found between TC and Vit E (r = 0.5575; p < 0.001), LPO and PL (r = 0.4270; p < 0.01), LPO and GST (r = 0.3770; p < 0.01) and t-SH and GPx (r = 0.3781; p < 0.01) in smokers. These findings reveal a disturbance of oxidant-antioxidant balance by free radicals present in cigarette smoke, which may cause reduction in platelet hyperreactivity and endothelial dysfunction in smokers.

Oxidant and antioxidant systems in niddm patients: influence of vitamin E supplementation

Free radical-mediated oxidative stress has been implicated in adverse tissue changes in a number of diseases. In view of the role of oxidative processes in non-insulin dependent diabetes mellitus (NIDDM), in this study, we investigated the oxidant and antioxidant status of plasma in patients with NIDDM and the effect of vitamin E (800 lU/day) supplementation on oxidative stress, antioxidant defense system, fructosamine levels and insulin action. Thirty controls and 40 NIDDM patients were studied. In controls and patients, plasma lipids, vitamin E, lipid peroxide, total thiols (t-SH), superoxide peroxidase (SOD) and glutathione peroxidase (GPx) were measured in the basal state and after vitamin E (800 IU/d) supplementation for a month. All lipids and lipid fractions in plasma were significantly decreased, whereas the HDL-C level was changed in diabetic patients supplemented with vitamin E when compared with baseline values. Vitamin E administration also significantly reduced fasting glucose and fructosamine levels, whereas increased significantly reduced fasting glucose and fructosamine levels, whereas increased significantly plasma C-peptide and insulin levels (p < 0.01, p < 0.001, respectively). Following vitamin E supplementation, TBARs levels were found to be significantly lower (p < 0.001) than the baseline value NIDDM patients are. On the other hand, activities of GPx and SOD were significantly higher (p < 0.001) than baseline values. A similar trend was observed for total thiols contents, but in this case, the increase was not significant. In conclusion, this study demonstrates that vitamin E improved beta-cell function and increased plasma insulin and C-peptide levels, possibly by inducing the antioxidant capacity of the organism and/or reducing the peripheral resistance in NIDDM. Long-term studies are needed to demonstrate the beneficial effects of vitamin E on treatment/prevention of NIDDM.

Free radical defenses in the liver and kidney of human growth hormone transgenic mice: possible mechanisms of early mortality

The long-term effects of growth hormone (GH) administration are unknown. Although limited data on its short-term effects purport health benefits, numerous detrimental effects are the consequence of chronically elevated GH. We used spectrophotometric assay and Western blot to determine the effects of chronic GH excess on hepatic and renal antioxidant enzymes (AOEs) in young and middle-aged PEPCK (phosphoenolpyruvate carboxykinase) hGH (human GH) transgenic mice. In the liver, glutathione peroxidase (GPx) was reduced in transgenics of both age groups, catalase was reduced only in young transgenics, and Cu-Zn superoxide dismutase (SOD) was similar to normal mice, but declined with age. In all groups, hepatic AOE activity correlated significantly with AOE level. In the kidney, AOEs in young transgenics were similar to those of normal mice. However, middle-aged transgenics showed reduced renal SOD and GPx activities when compared with young transgenic or middle-aged normal mice. Similarly, renal SOD and GPx levels in middle-aged transgenics were reduced when compared with those of middle-aged normal mice. AOE activity in the kidney correlated significantly with AOE protein level among middle-aged animals only. These data suggest the following: ((1)) GH excess is associated with early declines in SOD and GPx in the kidney and reductions of hepatic GPx at all ages examined, perhaps increasing the risk of free radical-induced damage to these tissues; ((2)) in the liver of young animals and in the liver and kidney of middle-aged animals, AOE activity reflects the amount of enzyme protein; and ((3)) age-related reductions in GPx in transgenics may be related to the increased incidence of liver tumors and renal failure in these animals.

Effects of growth hormone on hypothalamic catalase and Cu/Zn superoxide dismutase

Age-associated changes in hypothalamic catalase activity and level, and Cu/Zn superoxide dismutase (Cu/Zn SOD) activity were examined in Ames dwarf mice with growth hormone (GH) deficiency and prolonged lifespan, in PEPCK-hGH transgenic mice with overexpression of GH and reduced lifespan, and compared to values measured in normal controls. Hypothalami from young (3-4 months), middle-aged (9-10 months), and old (19-23 months) male mice were examined using spectrophotometric assay and Western blot. In dwarf mice, Cu/Zn SOD and catalase activities declined with age, and were higher than the corresponding normal values in young and middle-aged groups. Catalase levels also declined with age, but were similar to values in normal controls. In GH transgenic mice, age-associated decline of both catalase and Cu/Zn SOD occurred earlier than in normal animals. Catalase levels and activities in transgenic animals were similar to controls, whereas Cu/Zn SOD activity was higher in transgenics than in normal mice. The present results suggest that dwarf mice, during early life, have enhanced hypothalamic free radical defenses, which may contribute to their extended lifespan. However, from the present results in GH transgenic mice, it is impossible to conclude whether early decline of hypothalamic catalase and Cu/Zn SOD in these animals represents a correlate of accelerated aging, or contributes to their reduced lifespan.

Early captopril prevents myocardial infarction-induced hypertrophy but not angiogenesis

Delayed captopril, started after the healing phase of myocardial infarction, improves perfusion by reducing tissue weight without affecting the vascular capacity of the heart. Early captopril, during the healing phase, prevents reactive hypertrophy, but the effects on angiogenesis are unknown. Therefore, the effects of early captopril (2 g/l drinking water, from 1 day until 3 weeks after myocardial infarction) on regional coronary flow related to tissue mass, were studied in isolated perfused hearts from rats, subjected to coronary artery ligation. Regional maximal vascular capacity was measured during nitroprusside-induced vasodilation, using radioactive microspheres. Maximal vascular capacity was not changed by captopril. Reactive hypertrophy in infarcted hearts only reached statistical significance in the left ventricular free wall. Since captopril prevented hypertrophy but did not affect regional capacity, peak tissue perfusion was improved. Indicating effects on metabolism, captopril restored the increased lactate/purine ratio in infarcted hearts. Thus, early captopril treatment prevented post-myocardial infarction hypertrophy but did not suppress angiogenesis, thus beneficially influencing the vascularization/tissue mass ratio, probably reflected by preservation of aerobic metabolism.

Superoxide dismutase, catalase and glutathione peroxidase activities in human blood: influence of sex, age and cigarette smoking

OBJECTIVE

To obtain reference ranges for each of the main antioxidant enzymes (AOE) and analyze the influence of sex, age, and cigarette smoking on AOE activity in human blood.

DESIGN AND METHODS

We investigated superoxide dismutase (SOD), catalase (CAT), and seleno-dependent glutathione peroxidase (GSH-Px) activities in the whole blood from 103 healthy subjects, from 18-67 years old (51 males and 52 females).

RESULTS

We found a large and highly significant interindividual variability in the activity of all the AOE studied (p < 0.001). The interindividual coefficients of variation were 13.5% for SOD, 21.0% for CAT, and 36.2% for GSH-Px, indicating that GSH-Px exhibits the highest interindividual variability. Females showed higher SOD (p < 0.001) and CAT (p < 0.001) activities but lower GSH-Px (p < 0.05) activity than males. We found a significant effect of age on SOD activity (p < 0.001), showing that in human blood it decreases with age and that this decrease is not linear, beginning at 28 years of age. We also observed a linear effect of age on GSH-Px activity indicating that the activity of this enzyme increases with age (p < 0.01). No effect of age on CAT activity was observed (p > 0.05). AOE activity in smokers was found not to be significantly different from that observed in non-smokers (p > 0.05) except in the case of CAT activity in females, which was found to be lower in smokers than in non-smokers (p < 0.05). In addition, we determined reference ranges for the activity of each antioxidant enzyme studied.

CONCLUSIONS

Our results confirm that AOE activity in human blood exhibits a wide interindividual variability and suggest that this variability may be ascribed, at least in part, to the sex and age of the individuals. Moreover, our results suggest that cigarette smoking does not influence AOE activity in human blood. Accordingly, it is suggested that for clinical purposes it may be necessary to consider the sex and age of the subjects involved in the study.

Relationship between pituitary hormones, antioxidant enzymes, and histopathological changes in the mammary gland of senescent rats

In order to assess the possible involvement of endocrine factors and antioxidant enzymes (AOE) in the mammary pathology typically observed in old female rats, we undertook to determine the relationship between pituitary hormones, AOE activity, and histopathological changes in the mammary gland of senescent rats carrying neoplastic and nonneoplastic mammary pathologies. Serum levels of several pituitary hormones were determined by RIA in young (five months) and senescent (33 months) Sprague-Dawley female rats. The activity of catalase (CAT) and superoxide dismutase (SOD) in mammary tissue from the senescent animals was also determined. Senescent rats showed higher levels of prolactin (PRL) (p < 0.01), thyroid-stimulating hormone (TSH) (p < 0.05) and follicle-stimulating hormone (FSH) (p < 0.01) than their young counterparts. In senescent females the main histopathological findings at mammary level were a marked hyperplasia and the presence of fibroadenomas. In this group there was a positive correlation between serum levels of PRL and the activity of mammary SOD (p < 0.05). There was also a positive correlation between serum levels of FSH and the activity of mammary CAT (p < 0.001). Young females, rendered moderately hyperprolactinemic by means of anterior pituitary grafts, showed clear proliferative changes in their mammary glands. Senescent rats carrying fibroadenomas were less hyperprolactinemic than those with mammary hyperplasia (p < 0.05). Our results provide additional support to the idea that PRL may be a physiological modulator of mammary SOD activity and suggest that FSH can possibly influence the activity of CAT in mammary gland. They also suggest that tumorigenesis but not hyperplasia in rat mammary gland may be associated with low mammary SOD and CAT activities.