Cardioprotection by Farnesol: Role of the Mevalonate Pathway

Purpose

Farnesol is a key metabolite of the mevalonate pathway and known as an antioxidant. We examined whether farnesol treatment protects the ischemic heart.

Methods

Male Wistar rats were treated orally with 0.2, 1, 5, and 50 mg/kg/day farnesol/vehicle for 12 days, respectively. On day 13, the effect of farnesol treatment on cardiac ischemic tolerance and biochemical changes was tested. Therefore, hearts were isolated and subjected either to 30 min coronary occlusion followed by 120 min reperfusion to measure infarct size or to 10 min aerobic perfusion to measure cardiac mevalonate pathway end-products (protein prenylation, cholesterol, coenzyme Q9, coenzyme Q10, dolichol), and 3-nitrotyrosine (oxidative/nitrosative stress marker), respectively. The cytoprotective effect of farnesol was also tested in cardiomyocytes subjected to simulated ischemia/reperfusion.

Results

Farnesol pretreatment decreased infarct size in a U-shaped dose–response manner where 1 mg/kg/day dose reached a statistically significant reduction (22.3?±?3.9 % vs. 40.9?±?6.1 % of the area at risk, p?<?0.05). Farnesol showed a similar cytoprotection in cardiomyocytes. The cardioprotective dose of farnesol (1 mg/kg/day) significantly increased the marker of protein geranylgeranylation, but did not influence protein farnesylation, cardiac tissue cholesterol, coenzyme Q9, coenzyme Q10, and dolichol. While the cardioprotective dose of farnesol did not influence 3-nitrotyrosine, the highest dose of farnesol (50 mg/kg/day) tested did not show cardioprotection, however, it significantly decreased cardiac 3-nitrotyrosine.

Conclusions

This is the first demonstration that oral farnesol treatment reduces infarct size. The cardioprotective effect of farnesol likely involves increased protein geranylgeranylation and seems to be independent of the antioxidant effect of farnesol.     

Activity of Superoxide Dismutase, Catalase, Glutathione Peroxidase, and Glutathione Reductase in Different Stages of Colorectal Carcinoma

Background

Reactive oxygen species are involved in the pathogenesis of colorectal carcinoma. Clarification of oxidative/antioxidant specificities of different stages of colorectal carcinoma is of special importance.

Aim

To determine oxidative/antioxidant status in plasma of patients with different stages of colorectal carcinoma using malondialdehyde concentration, superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase activities and distribution of superoxide dismutase isoforms.

Methods

Lipid peroxidation and antioxidant enzymes activity were estimated using spectrophotometric methods. Reverse zymography was applied for characterization of superoxide dismutase isoforms.

Results

Lipid peroxidation is increased in all groups compared to the control, but without differences between different stages of colorectal carcinoma. Total superoxide dismutase activity is lower in all colorectal carcinoma groups than in control, and there is a significant increase in tumor stage IV when compared with tumor stage II. Manganese superoxide dismutase isoform is dominant in all groups and its relative activities are significantly higher than activities of a copper/zinc isoform. Total peroxidase potential reflected in catalase and glutathione peroxidase activity is increased when compared to the control, but without any significant differences between colorectal carcinoma groups. Glutathione reductase activity is lower in all colorectal carcinoma groups than in control, and a significant decrease in glutathione reductase activity was obtained between patients in tumor stage II and III compared to tumor stage IV.

Conclusions

Colorectal carcinoma is characterized by increased oxidative stress and antioxidant disbalance. Progression of disease is followed by an increase in redox disbalance.     

Purified Micronized Flavonoid Fraction Ameliorates the Injury of Spleen and Ileum Secondary to Hepatic Ischemia–Reperfusion in Rats

Background

Flavonoids have been subjected to considerable investigations due to their antioxidant and anti-inflammatory properties. Yet the effects of flavonoids on the ileum and spleen against hepatic ischemia–reperfusion injury have so far not been addressed.

Aims

We aimed to investigate whether micronized purified flavonoid fraction (MPFF) protects the ileum and spleen against hepatic ischemia–reperfusion injury.

Methods

Rats were subjected to hepatic ischemia by clamping the hilar area of the rats for 60 min, followed by 60 min of reperfusion. Rats in the treatment group were treated with MPFF (80 mg/kg/day) by gavage for 3 days before surgery, 30 min prior to ischemia and just before the reperfusion. After the reperfusion period, all rats were sacrificed. Ileal and splenic tissues were taken for histological evaluation and determination of the total antioxidant capacity (TAC), catalase, total oxidant status (TOS), oxidative stress index (OSI) and myeloperoxidase (MPO) levels.

Results

TAC levels in the splenic tissue and intestinal tissue were significantly higher in the treatment group than in the control group (P < 0.01 for both). TOS, OSI, and MPO in splenic tissue (P < 0.01, P < 0.05, and P < 0.05, respectively) and intestinal tissue (P < 0.01, P < 0.01, and P < 0.001, respectively) were significantly lower in the treatment group than in the control group. Histological tissue damage of intestinal tissue was milder in the treatment group than in the control group.

Conclusion

The results of this study indicated that MPFF pretreatment significantly limited the injury to the small intestine and spleen induced by hepatic ischemia–reperfusion in rats.     

Preclinical Efficacy of Melatonin to Reduce Methotrexate-Induced Oxidative Stress and Small Intestinal Damage in Rats

Background

Methotrexate is widely used as a chemotherapeutic agent for leukemia and other malignancies. The efficacy of this drug is often limited by mucositis and intestinal injury, which are the major causes of morbidity in children and adults.

Aim

The present study investigates whether melatonin, a powerful antioxidant, could have a protective effect.

Method

Rats were pretreated with melatonin (20 and 40 mg/kg body weight) daily 1 h before methotrexate (7 mg/kg body weight) administration for three consecutive days. After the final dose of methotrexate, the rats were sacrificed and the small intestine was used for light microscopy and biochemical assays. Intestinal homogenates were used for assay of oxidative stress parameters malondialdehyde and protein carbonyl content, and myeloperoxidase activity, a marker of neutrophil infiltration as well as for the activities of the antioxidant enzymes.

Result

Pretreatment with melatonin had a dose-dependent protective effect on methotrexate (MTX)-induced alterations in small intestinal morphology. Morphology was saved to some extent with 20 mg melatonin pretreatment and near normal morphology was achieved with 40 mg melatonin pretreatment. Biochemically, pretreatment with melatonin significantly attenuated MTX-induced oxidative stress (P < 0.01 for MDA, P < 0.001 for protein carbonyl content) and restored the activities of the antioxidant enzymes (glutathione reductase P < 0.05, superoxide dismutase P < 0.01).

Conclusion

The results of the present study demonstrate that supplementation by exogenous melatonin significantly reduces MTX-induced small intestinal damage, indicating that it may be beneficial in ameliorating MTX-induced enteritis in humans.     

Catalase,superoxide dismutase,and glutathione peroxidase activities in various rat tissues after carbon tetrachloride intoxication

Background. The aim of this study was to determine the possible relationship between the activity of three different antioxidant enzymes — peroxidase superoxide dismutase, catalase, and glutathione peroxidase — and carbon tetrachloride-induced injury. Methods. Male Wistar rats weighing 200–250?g were used in the experiments. Rats of the experimental groups were given carbon tetrachloride 0.5?ml/kg i.p. in olive oil (5?mmol/kg body mass) for 1 or 3 days. Control group rats were injected with olive oil only for the same period. Brain, liver, kidney, and heart supernatants were used for measurement of superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPX) activities. Results. No statistically significant changes in SOD and GPX activities were observed in the liver after CCl₄ administration, but catalase activity was significantly increased after 24?h and remained at that level during the course of the study. In the brain, SOD and catalase activities decreased after 24?h of experiment, but GPX activity statistically significantly increased at all time points studied. Increased activities of SOD, catalase, and GPX were found in heart after CCl₄ intoxication. The CCl₄ injection in our experiment caused a reduction of SOD and catalase activities and increased GPX activity in the kidney. Conclusions. The results suggest that change in antioxidant enzyme activities may be relevant to the ability of the liver and other investigated organs to cope with oxidative stress during CCl₄ poisoning.     

Exaggerated Liver Injury Induced by Renal Ischemia Reperfusion in Diabetes: Effect of Exenatide

Background/Aim:

This study was designed to investigate the possible effect of exenatide (Glucagon like Peptide-1 receptor agonist) on liver injury (distant organ) induced by renal ischemia reperfusion (IR) in diabetic rats.

Materials and Methods:

In vivo renal IR was performed in both type 2 diabetic and normal rats. Each protocol comprised ischemia for 30 minutes followed by reperfusion for 24 hours and a treatment period of 14 days before induction of ischemia.

Results:

Lipid peroxidation, xanthine oxidase activity, myeloperoxidase activity and nitric oxide level in liver tissue were significantly increased (P < 0.01, P < 0.001, P < 0.001, P < 0.05, respectively), after IR in diabetic rats compared to normal rats. Antioxidant enzymes like glutathione, superoxide dismutase, catalase and glutathione peroxidase were significantly reduced (P < 0.05, P < 0.05, P < 0.01, P < 0.05, respectively), after IR in diabetic rats compared to normal rats. Exenatide treatment significantly normalized (P < 0.01), these biochemical parameters in treated rats compared to diabetic IR rats. Serum creatinine phosphokinase activity and liver function enzymes were also significantly normalized (P < 0.001, P < 0.001, respectively), after administration of exenatide.

Conclusion:

Exenatide exerted protective effect on exaggerated remote organ (liver) injury induced by renal IR in diabetes.     

Hypothyroidism impairs antioxidant defence system and testicular physiology during development and maturation

In the present study, effects of transient hypothyroidism (from birth to 30 days) and persistent hypothyroidism (from birth to 90 days) on testicular antioxidant defence system of mature rats were compared in order to know the role of hypothyroidism induced oxidative stress in testicular development and maturation. Rats were made hypothyroid by feeding lactating mothers and adult rats with 0.05% 6-n-propyl thiouracil (PTU) in drinking water. PTU treatment for 30 days or for 90 days to rats from birth resulted in a decrease in body weight at the age of 90 days in comparison to the controls. The testicular germ cell counts were significantly decreased in persistent hypothyroid rats whereas they were increased in the transient hypothyroid rats. However, a significant reduction in the number of live sperms in epididymis of both 30 day and 90-day PTU treated rats was noticed on 90 days of age. Mitochondrial lipid peroxidation (LPx) levels were decreased in transient hypothyroidism whereas LPx and protein carbonylation were elevated during persistent hypothyroidism in the testis. Reduced testicular superoxide dismutase (SOD), catalase and glutathione reductase (GR) and glutathione peroxidase (GPx) activities were marked during transient hypothyroidism. In contrast, an elevation in SOD (PMF) and catalase activities with a significant decline in GPx and GR activities was found following persistent hypothyroidism. Marked histological changes were observed in the testis of both experimental groups. These results suggest a direct regulatory role of thyroid hormone on testicular physiology and antioxidant defence system during development and maturation.     

Oxidative and nitrosative stress induces peroxiredoxins in pancreatic beta cells

AIMS/HYPOTHESIS: Insulin-producing beta cells are destroyed by oxidative and nitrosative stress during the pathogenesis of Type I (insulin-dependent) diabetes mellitus. These cells are more sensitive than others due to their deficiency of well known antioxidant enzymes like superoxide dismutase, glutathione peroxidase and catalase. However the peroxiredoxins discovered in the past decade form a large family of highly conserved thioredoxin-dependent peroxide reductases, which are present in most tissues. We investigated whether peroxiredoxins I and II are present in pancreatic beta cells and if they are inducible by oxidative and nitrosative stress. METHODS: To detect these enzymes in insulin-producing beta cells we used semiquantitative RT-PCR, western blots and immunohistochemistry. The expression of peroxiredoxins I and II was analysed after treatment with cytokines, hydrogen peroxide, alloxan or streptozotocin in the rat insulinoma cells INS-1 using RT-PCR and western blots. RESULTS: We show that peroxiredoxins I and II are present in the cytoplasm of pancreatic islet cells as well as in insulinoma cell lines beta TC6-F7 and INS-1. Peroxiredoxins I and II were up-regulated by all stress agents used. CONCLUSION/INTERPRETATION: Beta cells, undersupplied with well characterized antioxidant enzymes, possess an additional antioxidant system which is inducible by oxidative as well as nitrosative stress.     

Tramadol Alleviates Myocardial Injury Induced by Acute Hindlimb Ischemia Reperfusion in Rats

Background

Organ injury occurs not only during periods of ischemia but also during reperfusion. It is known that ischemia reperfusion (IR) causes both remote organ and local injuries.

Objective

This study evaluated the effects of tramadol on the heart as a remote organ after acute hindlimb IR.

Methods

Thirty healthy mature male Wistar rats were allocated randomly into three groups: Group I (sham), Group II (IR), and Group III (IR + tramadol). Ischemia was induced in anesthetized rats by left femoral artery clamping for 3 h, followed by 3 h of reperfusion. Tramadol (20 mg/kg, intravenous) was administered immediately prior to reperfusion. At the end of the reperfusion, animals were euthanized, and hearts were harvested for histological and biochemical examination.

Results

The levels of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were higher in Groups I and III than those in Group II (p < 0.05). In comparison with other groups, tissue malondialdehyde (MDA) levels in Group II were significantly increased (p < 0.05), and this increase was prevented by tramadol. Histopathological changes, including microscopic bleeding, edema, neutrophil infiltration, and necrosis, were scored. The total injuryscore in Group III was significantly decreased (p < 0.05) compared with Group II.

Conclusion

From the histological and biochemical perspectives, treatment with tramadol alleviated the myocardial injuries induced by skeletal muscle IR in this experimental model.     

Safranal ameliorates antioxidant enzymes and suppresses lipid peroxidation and nitric oxide formation in aged male rat liver

Free radical production and oxidative stress are known to increase in liver during aging, and may contribute to oxidative damage. The objective of this study was to observe the changes in activities of antioxidant enzymes (superoxide dismutase, glutathione-S-transferase, catalase), lipid peroxidation levels and serum nitric oxide occurring in livers of rats of 2, 10 and 20 months old, and to see whether these changes are restored to those of the two month old control levels rats after administration of safranal. The aged rats (10 and 20 months) were given intraperitoneal injections of safranal (0.5 mg/kg day) daily for one month. The results obtained in the present work revealed that normal aging was associated with a significant decrease in the activities of antioxidant enzymes, and an increase in lipid peroxidation in livers and nitric oxide content in serum of aging rats. The results of the present study demonstrate that safranal could be a candidate to suppress the development of age-induced damage by protecting against oxidative stress and increasing antioxidant defenses. A likely mode of action of safranal can be its activity as a hormetin by inducing mild oxidative damage which leads to the activation of antioxidative enzymes.     

Protective Effect of Grape Seed and Skin Extract Against High-Fat Diet-Induced Liver Steatosis and Zinc Depletion in Rat

Background

Obesity is a tremendous public health problem, characterized by ectopic deposition of fat into non-adipose tissues as liver generating an oxidative stress that could lead to steato-hepatitis. Grape seed and skin extract (GSSE) is a complex mixture of polyphenolics exhibiting robust antioxidative properties.

Aim

We hypothesize that GSSE could protect the liver from fat-induced lipotoxicity and have a beneficial effect on liver function.

Methods

Hepatoprotective effect of GSSE was measured by using an experimental model of fat-induced rat liver steatosis. Male rats were fed a standard diet or a high-fat diet (HFD) during 6 weeks and treated or not with 500 mg/kg bw GSSE. Lipid deposition into the liver was assessed by triglyceride, cholesterol and phospholipid measurements. Fat-induced lipoperoxidation, carbonylation, depletion of glutathione and of antioxidant enzyme activities were used as oxidative stress markers with a special emphasis on transition metal distribution.

Results

HFD induced liver hypertrophy and inflammation as assessed by high liver transaminases. HFD also induced an oxidative stress characterized by increased lipid and protein oxidation, a drop in glutathione and antioxidant enzyme activities as glutathione peroxidase and superoxide dismutase and a drastic depletion in liver zinc. Importantly, GSSE prevented all the deleterious effects of HFD treatment.

Conclusions

Data suggest that GSSE could be used as a safe preventive agent against fat-induced liver lipotoxicity which could also have potential applications in other non-alcoholic liver diseases.     

Copper(II)-selective chelation improves function and antioxidant defences in cardiovascular tissues of rats as a model of diabetes: comparisons between triethylenetetramine and three less copper-selective transition-metal-targeted treatments

Aims/hypothesis

Treatment with the Cu(II)-selective chelator triethylenetetramine (TETA) improves cardiovascular disease in human patients, and cardiac and vascular/renal disease in rats used as a model of diabetes. Here we tested two hypotheses: first, that TETA elicits greater improvement in organ function than less Cu-selective transition-metal-targeted treatments; second, that the therapeutic actions of TETA are consistent with mediation through suppression of oxidative stress.

Methods

Rats were made diabetic with streptozotocin (55 mg/kg, i. v.) and treated from 8 weeks after disease induction for the following 8 weeks with effective dosages of oral TETA, or one of three less Cu-selective transition-metal-targeted treatments: d-penicillamine, deferiprone or Zn acetate. Treatment effects were measured in ex vivo cardiac and aortic tissues, plasma and urine.

Results

Diabetes damaged both cardiac and renal/vascular function by impairing the ability of cardiac output to respond physiologically to rising afterload, and by significantly elevating the urinary albumin/creatinine ratio. Diabetes also lowered total antioxidant potential and heparan sulphate levels in cardiac and arterial tissues, and serum ferroxidase activity, whereas it elevated urinary heparan sulphate excretion. TETA treatment rectified or partially rectified all these defects, whereas the other three experimental treatments were ineffectual. By contrast, none of the four drug treatments lowered diabetes-mediated elevations of plasma glucose or lipid concentrations.

Conclusions/interpretation

TETA may limit the cardiac and renal/vascular damage inflicted by diabetes through its actions to reinforce antioxidant defence mechanisms, probably acting through selective chelation of ‘loosely-bound’/chelatable Cu(II). It may also improve heparan sulphate homeostasis and bolster antioxidant defence by increasing vascular extracellular superoxide dismutase activity. Urinary albumin/creatinine ratio might prove useful for monitoring TETA treatment.     

Effect of Carnitine and herbal mixture extract on obesity induced by high fat diet in rats

Background

Obesity-associated type 2 diabetes is rapidly increasing throughout the world. It is generally recognized that natural products with a long history of safety can modulate obesity.

Aim

To investigate the development of obesity in response to a high fat diet (HFD) and to estimate the effect of L-carnitine and an Egyptian Herbal mixture formulation (HMF) (consisting of T. chebula, Senae, rhubarb, black cumin, aniseed, fennel and licorice) on bodyweight, food intake, lipid profiles, renal, hepatic, cardiac function markers, lipid Peroxidation, and the glucose and insulin levels in blood and liver tissue in rats.

Method

White male albino rats weighing 80-90 gm, 60 days old. 10 rats were fed a normal basal diet (Cr), 30 rats fed a high-fat diet (HFD) for 14 weeks during the entire study. Rats of the HFD group were equally divided into 3 subgroups each one include 10 rats. The first group received HFD with no supplement (HFD), the 2^nd group HFD+L-carnitine and the third group received HFD+HMF. Carnitine and HMF were administered at 10^th week (start time for treatments) for 4 weeks. Body weight, lipid profile & renal function (urea, uric acid creatinine) ALT & AST activities, cardiac markers, (LDH, C.K-NAC and MB) the oxidative stress marker reduced glutathione (GSH), and Malondialdehyde (MDA) catalase activity, in addition to glucose, insulin, and insulin resistance in serum & tissues were analyzed.

Results

Data showed that feeding HFD diet significantly increased final body weight, triglycerides (TG), total cholesterol, & LDL concentration compared with controls, while significantly decreasing HDL; meanwhile treatment with L-carnitine, or HMF significantly normalized the lipid profile. Serum ALT, urea, uric acid, creatinine, LDH, CK-NAC, CK-MB were significantly higher in the high fat group compared with normal controls; and administration of L-carnitine or herbal extract significantly lessened the effect of the HFD. Hyperglycemia, hyperinsulinemia, and high insulin resistance (IR) significantly increased in HFD in comparison with the control group. The treatment with L-carnitine or HMF improved the condition. HFD elevated hepatic MDA and lipid peroxidation associated with reduction in hepatic GSH and catalase activity; whereas administration of L-carnitine or herbal extract significantly ameliorated these hepatic alterations.

Conclusion

HFD induced obesity associated with a disturbed lipid profile, defective antioxidant stability, and high values of IR parameters; this may have implications for the progress of obesity related problems. Treatment with L-carnitine, or HMF extract improved obesity and its associated metabolic problems in different degrees. Also HMF has antioxidant, hypolipidaemic insulin sensitizing effects. Moreover HMF might be a safe combination on the organs whose functions were examined, as a way to surmount the obesity state; and it has a distinct anti-obesity effect.     

Comparative proteomic analysis of human donor tissues during orthotopic liver transplantation: ischemia versus reperfusion

Purpose

To explore the specific alterations in protein profiles that occur during ischemia/reperfusion injury (I/RI) and find novel therapeutic strategies to reduce I/RI during orthotopic liver transplantation (OLT).

Method

We used the comparative proteomic approach of two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to compare the proteomic profiles of the same donor liver at three different time points: T1, immediately after cardiac arrest of donors (normal control); T2, before portal vein anastomosis (ischemia); and T3, 2 h after hepatic artery anastomosis (reperfusion).

Result

We identified 34 proteins that were significantly altered during I/RI. These differentially expressed proteins were functionally classified into seven categories: metabolic enzyme, molecular chaperone, antioxidant enzyme, cytoskeleton protein, signal transduction protein, cyclin, and binding protein. Among the 34 proteins, 9 changed during ischemia only (from T1 to T2), 11 changed during reperfusion only (from T2 to T3), and the others changed during both ischemia and reperfusion (from T1 to T3) periods.

Conclusion

Ischemia and reperfusion during LT may lead to different modifications of the liver proteins. Most metabolic enzymes and antioxidant enzymes were upregulated during ischemia, indicating that lipid metabolic disorder and oxidative stress are closely related to the development of ischemic injury. ER chaperones may play a vital role in mediating I/RI and preventing ER stress caused by I/RI. Modulation of ER chaperones could be used as a key therapeutic target to improve the outcomes of LT.     

Protective Effects of Thymoquinone and Melatonin on Intestinal Ischemia–reperfusion Injury

Background/Aim:

In the present study, we aimed to compare the potential protective effects of thymoquinone and melatonin by using equivalent dose, on oxidative stress-induced ischemia–reperfusion (IR) injury in the intestinal tissue of rats.

Materials and Methods:

The study was performed using 32 male Wistar–Albino rats (weighing 180–200 g) randomly divided into four groups: Group I, sham group; Group II, IR group; Group III, IR with melatonin group; and Group IV, IR with thymoquinone group. After laparotomy, ischemia and reperfusion were performed for 60 and 120 min, respectively, on all the groups. Intestinal tissue sections were stained using routine histological methods and examined under the light microscope. In addition, the sections were immunohistochemically stained using the TUNEL method for determination of apoptosis. Superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity, and malondialdehyde (MDA) levels in the intestinal tissue were also measured.

Results:

The IR group had significantly elevated tissue SOD activity, GSH-Px activity, and MDA levels compared with the sham group. Administration of thymoquinone and melatonin efficiently reduced these increases. Statistically significant number of apoptotic cells was observed in the intestinal tissue of IR group rats compared with the sham group. Treatment with thymoquinone and melatonin markedly reduced the number of apoptotic cells.

Conclusion

The effects of melatonin and thymoquinone on IR-induced oxidative stress in rat intestines were similar. Our findings suggest that melatonin and thymoquinone protect against IR-induced injury to intestinal tissues.     

Different Profile of Peripheral Antioxidant Enzymes and Lipid Peroxidation in Active and Non-active Inflammatory Bowel Disease Patients

Background

The role of oxidative stress in inflammatory bowel diseases (IBD) has been extended lately from a simple consequence of inflammation to a potential etiological factor, but the data are still controversial. Active disease has been characterized before by an enhanced production of reactive oxygen species and the increased peroxidation of lipids, but patients in remission were generally not considered different from healthy people in terms of oxidative stress.

Aims

We evaluated the antioxidant defense capacity and lipid peroxidation status in the serum of patients with active and non-active disease compared with healthy matched control subjects.

Methods

The study included 20 patients with confirmed IBD in clinical and biological remission, 21 patients with active disease, and 18 controls. We determined the serum levels of two antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GPX), and a lipid peroxidation marker, malondialdehyde (MDA).

Results

Active disease patients had an increased activity of both SOD and GPX, as well as significant high values of MDA versus controls. Furthermore, patients being in remission had significantly lower values of antioxidant enzymes (SOD and GPX) and increased lipid peroxidation measured by MDA serum levels, as compared with healthy control subjects.

Conclusions

Our study confirmed the presence of high oxidative stress in active IBD. More importantly, we have demonstrated a lower antioxidant capacity of patients in remission versus control group. This may represent a risk factor for the disease and can be an additional argument for the direct implication of oxidative stress in the pathogenesis of IBD.     

Superoxide dismutase, catalase and glutathione peroxidase in the spontaneously hypertensive rat kidney: effect of antioxidant-rich diet

BACKGROUND AND OBJECTIVE: Earlier studies have shown increased production of reactive oxygen species (ROS) and upregulation of ROS-generating enzyme, nicotinamide adenine dinucleotide (phosphate) oxidase, in the kidney of spontaneously hypertensive rats (SHR). This study aimed to examine the activities and protein abundance of the main antioxidant enzymes [i.e. superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX)] in the kidney of SHR fed a regular or an antioxidant-rich diet. METHODS: Pregnant SHR and their offspring were fed either a regular diet or an antioxidant-rich diet (alpha-tocopherol, ascorbic acid, zinc and selenium) and observed for 6 months. Wistar-Kyoto (WKY) rats fed a regular or antioxidant-fortified diet served as controls. RESULTS: The untreated SHR showed severe hypertension and significant increases in plasma hydrogen peroxide and renal tissue nitrotyrosine abundance, indicating the presence of oxidative/nitrosative stress. Despite oxidative stress, Cu Zn SOD, CAT and GPX activities were unchanged in the cortex and medulla of untreated SHR. Immunodetectable Mn SOD was reduced in the medulla and elevated in the cortex, whereas, Cu Zn SOD protein was unchanged in the cortex and reduced in the medulla. By contrast, CAT protein abundance was increased in both cortex and medulla while GPX protein was elevated in the cortex and unchanged in the medulla. Comparison of protein abundance and activities of the antioxidant enzymes revealed significant discordance in the untreated SHR. Lifelong antioxidant therapy diminished the severity of hypertension, improved oxidative stress and ameliorated or reversed abnormalities of antioxidant enzyme expressions and activities. By contrast, antioxidant therapy had no effect on the measured parameters in the WKY rat controls. CONCLUSIONS: Oxidative stress in SHR was associated with a lack of coordinate upregulation of the antioxidant enzymes and discordance between their protein abundance and enzymatic activity. These findings suggest an impaired antioxidant defense system and the presence of functionally abnormal enzymes in the SHR kidney. Lifelong antioxidant therapy improved expression, activity and activity-to-mass relationship of the measured enzymes. The latter suggests oxidative and nitrosative modification of these molecules in the SHR kidney.     

Oxidative stress. An early phenomenon characteristic of acute experimental pancreatitis.

Acute hemorrhagic pancreatitis was induced in Wistar rats using a retrograde intraductal injection of 5% Na-taurocholate. Rats were sacrificed at 1, 3, 6, and 24 h. Malondialdehyde and sulfhydryl groups concentration, as well as superoxide dismutase and catalase activity were measured in pancreatic, liver, and lung tissue. These parameters, with the exception of catalase, were also determined in serum and peritoneal exudate. Early and profound oxidative stress in each organ was evidenced by marked increases in malondialdehyde concentrations along with marked reductions in levels of sulfhydryl groups and superoxide dismutase; a paradoxical increase in catalase activity, perhaps compensatory, was noted in pancreas and lung. Survival for 24 h was associated with restoration of normality insofar as tissue malondialdehyde concentrations were concerned, but pancreas sulfhydryl groups remained markedly depleted. These data endorse the suggestion that the early provision of such compounds may help to accelerate recovery from hemorrhagic pancreatitis in humans.     

Lipid peroxidation and free radical scavengers in thyroid dysfunction in the rat: a possible mechanism of injury to heart and skeletal muscle in hyperthyroidism

This study was designed to determine if peroxidation of biomembrane lipid and the protective system can be modified by the change in oxidative metabolism induced by thyroid dysfunction. The free radical scavengers (i.e. cuprozinc cytosolic and mangano mitochondrial superoxide dismutases, glutathione peroxidase, and catalase), mitochondrial oxidative marker enzymes (cytochrome c oxidase and fumarase), and lipid peroxide were measured in liver, heart, soleus (slow oxidative), and extensor digitorum longus (fast glycolytic) muscles. Rats were rendered hyper- or hypothyroid for 4 weeks and then killed. Superoxide dismutases were detected by specific RIAs: catalase by polarography, and lipid peroxide by fluorimetry. Hypothyroid rats failed to grow, while hyperthyroid rats had hypertrophied hearts but no growth failure. An increase in lipid peroxide was observed in the soleus and heart muscles of hyperthyroid rats. This was accompanied by an increase in mitochondrial superoxide dismutase and oxidative markers. No such change was observed in either fast glycolytic muscle or liver. Glutathione peroxidase decreased in all tissues of hyperthyroid rats, and there was a parallel decrease in catalase in most tissues. On the other hand, hypothyroidism induced a reduction in oxidative markers and mitochondrial superoxide dismutase in heart and skeletal muscles, but only a marginal change in lipid peroxidation. The cytosolic superoxide dismutase did not change in relation to either oxidative metabolism or lipid peroxidation. These results suggest that the enhanced oxidative metabolism and decreased glutathione peroxidase in hyperthyroidism result in an increase in lipid peroxidation and, in slow oxidative and heart muscle, possible organ damage. No adverse reaction mediated by active oxygen species was found in hypothyroid rat tissues.