Hale Maral

Erythrocyte glutathione peroxidase activity, plasma malondialdehyde and erythrocyte glutathione levels in hemodialysis and CAPD patients

OBJECTIVES Cardiovascular disease is the major cause of mortality in patients receiving hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) due to chronic renal failure. Increased lipid peroxidation and depletion of antioxidants may contribute to increased risk of atherosclerosis. We have therefore assessed the effect of hemodialysis and CAPD on oxidant and antioxidant status. DESIGN AND METHODS Plasma malondialdehyde (MDA), Glutathione (GSH) levels and glutathione peroxidase (Gpx) activities were determined in 20 healthy persons (control), 20 patients on HD, 16 patients on CAPD. RESULTS MDA was elevated in posthemodialysis and CAPD patients in comparison to prehemodialysis and control groups (posthemodialysis 1.39 +/- 0.38 nmol/mL, CAPD 1.26 +/- 0.27 nmol/mL, prehemodilaysis 0.83 +/- 0.22 nmol/mL, controls 0.72 +/- 0.21 nmol/mL p < 0.0001). With respect to antioxidants, glutathione levels were significantly lower in prehemodialysis, posthemodialysis and CAPD groups than those in control group (prehemodialysis 16.82 +/- 6.73 mg/dL RBC, posthemodialysis 31.43 +/- 11.88 mg/dL RBC, CAPD 40 +/- 12.72 mg/dL RBC, controls 62.26 +/- 24.01 mg/dL RBC, p < 0.0001). While erythrocyte GSH levels were significantly lower in the prehemodialysis patients than those in posthemodialysis and CAPD patients (p < 0.0001), it was significantly lower in posthemodialysis patients than those in CAPD patients (p < 0.05). There were no significant differences with respect to erythrocyte Gpx levels among the groups (p > 0.05). CONCLUSIONS These findings indicate oxidative stress in patients with chronic renal failure which is further exacerbated by hemodialysis and CAPD, as evidenced by increased lipid peroxidation and low antioxidant levels.

Plasma lipid and lipoprotein concentrations in pregnancy induced hypertension.

OBJECTIVES Aim of this study was to evaluate implication of pregnancy induced hypertension on maternal plasma lipid, lipoprotein, apolipoprotein concentrations and lipid peroxidation products by a comparison of normal pregnancy vs. preeclampsia. DESIGN AND METHODS Thirty-four women with preeclampsia and 32 healthy pregnant women (controls) in the third trimester were recruited for this study. RESULTS In the preeclamptic group plasma total triglyceride, low density lipoprotein cholesterol (LDL-C), malondialdehyde (MDA) and apolipoprotein B (apo-B) were significantly increased, while plasma high density lipoprotein cholesterol (HDL-C) was significantly decreased compared to that of control group. There was no significant difference in total cholesterol and apolipoprotein A1 (apo-A1) concentrations. CONCLUSION Our findings suggest that preeclampsia share some metabolic characteristics with coronary artery disease such as dislipidemia and increased lipid peroxidation. However lipoprotein concentrations may be better biochemical markers of dislipidemia in the preeclamptic state than the corresponding apolipoproteins.

Malondialdehyde, glutathione, glutathione peroxidase and homocysteine levels in type 2 diabetic patients with and without microalbuminuria:

Background: High levels of homocysteine and oxidative stress are known to be associated with premature vascular disease in type 2 diabetes mellitus (DM). The aim of this study was to estimate homocysteine levels and oxidant-antioxidant status and to determine the relationship between them in type 2 diabetic patients with and without microalbuminuria. Methods: Fasting blood samples were obtained from 48 diabetic patients (17 with and 31 without microalbuminuria) and 20 healthy subjects. Serum total homocysteine (tHcy), plasma malondialdehyde (MDA) erythrocyte glutathione (GSH) and glutathione peroxidase (GPx) activity were measured in these patients and the results were compared with those of controls who were chosen among healthy subjects. Results: MDA levels were found to be significantly lower and GSH levels and GPx activities were found to be significantly higher in control subjects when compared with patients with and without microalbuminuria (MDA: P<0.0001, P<0.0001; GSH: P<0.0001, P<0.0001; GPx: P<0.0001, P<0.001, respectively). MDA levels were found to be significantly higher in patients with microalbuminuria compared with patients without microalbuminuria (P<0.0001), while similarly GSH levels were found to be significantly lower in patients with microalbuminuria (P<0.0001). Although there were no significant differences with respect to tHcy levels and GPx activities between the microalbuminuric and normoalbuminuric patients (P>0.05), there was a significant difference with respect to tHcy levels between healthy controls and patients with microalbuminuria (P<0.05). The serum levels of tHcy correlated best with plasma MDA and erythrocyte GSH concentrations in all diabetic patients (r=0.549, P<0.0001; r=0.385, P<0.01). Conclusion: Decreased antioxidant levels, increased lipid peroxidation and increased tHcy levels were observed in patients with microalbuminuria. These changes may contribute to vascular disease, which is particularly prevalent in type 2 DM patients with microalbuminuria.

Effects of erdosteine on bleomycin-induced lung fibrosis in rats

This study was designed to examine the effects of erdosteine on bleomycin (BLM)-induced lung fibrosis in rats. Thirty-three Sprague–Dawley rats were divided randomly into three groups, bleomycin alone (BLM), bleomycin + erdosteine (BLM + ERD), and saline alone (control). The BLM and BLM + ERD groups, were given 2.5 mg/kg BLM intratracheally. The first dose of oral erdosteine (10 mg/kg/day) in the BLM + ERD group was started 2 days before BLM administration and continued until animals were sacrificed. Animals were sacrificed 14 days after intratracheal instillation of BLM. The effect of erdosteine on pulmonary fibrosis was studied by analysis of bronchoalveolar lavage (BAL) fluid, histopathology, and biochemical measurements of lung tissue superoxide dismutase (SOD) and glutathione (GSH) as antioxidants, malondialdehyde (MDA) as an index for lipid peroxidation, and nitrite/nitrate levels. Bleomycin-induced lung fibrosis as determined by lung histology was prevented with erdosteine (grades of fibrosis were 4.9, 2.3, and 0.2 in BLM, BLM + ERD, and control groups, respectively). Erdosteine also prevented bleomycin-induced increase in MDA (MDA levels were 0.50 ± 0.15, 0.11 ± 0.02, and 0.087± 0.03 nmol/mg protein in BLM, BLM + ERD, and control groups, respectively) and nitrite/nitrate (nitrite/nitrate levels were 0.92 ± 0.06, 0.60 ± 0.09, and 0.56± 0.1 μmol/mg protein in BLM, BLM + ERD, and control groups respectively) levels. Bleomycin-induced decrease in GSH and SOD levels in the lung tissue also prevented by erdosteine [(GSH levels were 213.5 ± 12.4, 253.2± 25.2, and 287.9± 34.4 nmol/mg protein) (SOD levels were 1.42± 0.12, 1.75± 0.17, and 1.89± 0.09 U/mg protein) in BLM, BLM + ERD, and control groups respectively]. Erdosteine prevented bleomycin-induced increases in total cell number and neutrophil content of the BAL fluid. In conclusion, oral erdosteine is effective in prevention of BLM-induced lung fibrosis in rats possibly via the repression of neutrophil accumulation, inhibition of lipid peroxidation, and maintenance of antioxidant and free radical scavenger properties.

The effects of antioxidants on exercise‐induced lipid peroxidation in patients with COPD

Objective:  The oxidant–antioxidant balance plays an important role in the pathogenesis of COPD. The aim of the present study was to evaluate the effects of exercise, as an oxidative stress factor on the oxidant–antioxidant balance and to investigate whether short‐term antioxidant treatment affects lipid peroxidation products.

Protective antioxidant effects of carvedilol in a rat model of ischaemia- reperfusion injury

This study investigated the protective effects of carvedilol, a potent antioxidant, in a rat model of tourniquet-induced ischaemia-reperfusion injury of the hind limb. Thirty rats were divided equally into three groups: the control group (group 1) was only anaesthetized, without creating an ischaemia-reperfusion injury; group 2 was submitted to ischaemia (4 h), followed by a 2-h reperfusion period; and group 3 was pre-treated with carvedilol (2 mg/kg per day) for 10 days prior to ischaemia-reperfusion. Ischaemia-reperfusion produced a significant decrease in superoxide dismutase and glutathione peroxidase activities in the liver, lungs, muscle and serum compared with control treatment, and pre-treatment with carvedilol prevented these changes. Ischaemia-reperfusion caused a significant increase in malondialdehyde and nitric oxide (NO) levels in liver, lungs, muscle (except NO) and serum compared with control treatment, and carvedilol prevented these changes. In conclusion, it might be inferred that carvedilol could be used safely to prevent oxidative injury during reperfusion following ischaemia in humans.

Protective effects of N-acetylcysteine on peroxidative changes of the fetal rat lungs whose mothers were exposed to cigarette smoke:

Background: This experimental study investigated the protective effects of N-acetylcysteine (NAC) on peroxidative changes in fetal lungs in the offspring of rats exposed to cigarette smoke. Methods: Thirty fetal rats used for analysis, were divided into three groups as follows: control group (n = 10), whose mothers were exposed to fresh air; group I (n=10), whose mothers were exposed to cigarette smoke; and group II (n=10), whose mothers were exposed to cigarette smoke and given 10 mg/kg per day NAC. In groups I and II, smoke exposure was started 4 weeks before the pregnancy, and continued to the 14th day of pregnancy, and in Group II, NAC was administered intraperitoneally for 14 days. The mothers and their fetuses were decapitated on the 14th day of pregnancy. Malondialdehyde (MDA) and glutathione (GSH) levels were determined in the lung tissues of fetuses to determine the oxidant-antioxidant balance. Results: While tissue MDA levels in Group I were found significantly higher than the control group (129.7±65.4 versus 63.4±15.4 nmol/100 mg protein, P <0.05), GSH levels were significantly lower (17.1±7.3 versus 45.4±8.1 nmol/mg protein, P <0.01). Furthermore, in Group II, MDA levels were significantly lower (56.9± 20.6 versus 129.7±65.4 nmol/100 mg protein, P <0.05), and GSH levels were significantly higher (34.57±10.7 versus 17.1±7.3 nmol/mg protein, P <0.0001) when compared with Group I. No statistically significant difference was found in tissue MDA and GSH levels between Group II and the control group (P >0.05). Conclusions: These results suggest that smoke exposure during pregnancy causes oxidative damage in fetal lungs. This smoke-induced damage might be prevented by NAC. Human & Experimental Toxicology (2007) 26, 99-103

Effect of clopidogrel on nitric oxide levels in an ischemia reperfusion model.

Ischemia and reperfusion injury is a pathologic process with serious consequences, arising due to interruption of arterial blood flow. Restored blood flow achieved after the ischemic period causes formation of oxygen radicals by activation of a variety of substances and systems. In this study, we investigated the effect of clopidogrel, an antithrombocyte agent, on tissue nitric oxide (NO) levels in an experimental ischemia reperfusion model. For this purpose, 6 hours of ischemia and 4 hours of subsequent reperfusion were applied to the right lower extremities of the subjects. Clopidogrel therapy was started in one of these groups 10 days before the process (study group). NO levels were measured in all groups in the muscle, lung, and liver tissues, and in plasma. Lung, plasma, and liver NO measurement values had statistically significant differences among the groups. There was no statistically significant difference in the measurements made on the muscle tissue. Clopidogrel, which has previously been reported to be suitable to be used as a preventive agent of ischemia reperfusion damage, has had a reducing effect on the NO levels in tissues in the ischemia reperfusion model created in our present study.

Protective effects of N‐acetylcysteine on the peroxidative changes of rat lungs exposed to inhalation of thinners

Objective:  Long‐term inhalation of thinners may cause damage, both to the lungs and to other organ systems. It causes cellular damage via formation of reactive oxygen species. The lung is protected from oxidative stress by the glutathione (GSH) antioxidant system which can be augmented by the thiol drug, N‐acetylcysteine (NAC). This study investigated the protective effect of NAC on peroxidative changes in rat lungs exposed to inhalation of thinners for 8 weeks.

Effect of air bubble on inflammation after cataract surgery in rabbit eyes

Purpose: Intense inflammation after cataract surgery can cause cystoid macular edema, posterior synechia and posterior capsule opacification. This experimental study was performed to investigate the effect of air bubble on inflammation when given to anterior chamber of rabbit eyes after cataract surgery. Materials and Methods: 30 eyes of 15 rabbits were enrolled in the study. One of the two eyes was in the study group and the other eye was in the control group. After surgery air bubble was given to the anterior chamber of the study group eye and balanced salt solution (BSS; Alcon) was left in the anterior chamber of control eye. Results: On the first, second, fourth and fifth days, anterior chamber inflammations of the eyes were examined by biomicroscopy. On the sixth day anterior chamber fluid samples were taken for evaluation of nitric oxide levels as an inflammation marker. When the two groups were compared, in the air bubble group there was statistically less inflammation was seen. (1, 2, 4. days P = 0,001, and 5. day P = 0,009). Conclusions: These results have shown that when air bubble is left in anterior chamber of rabbits’ eyes after cataract surgery, it reduced inflammation. We believe that, air bubble in the anterior chamber may be more beneficial in the cataract surgery of especially pediatric age group, uveitis patients and diabetics where we see higher inflammation. However, greater and long termed experimental and clinical studies are necessary for more accurate findings.