Aysel Aricioglu

The effects of EGb 761 on lipid peroxide levels and superoxide dismutase activity in sunburn

Background/Purpose: Free oxygen radicals are involved in inflammatory skin reactions induced by ultraviolet B (UVB). In this study, the effect of a herbal antioxidant Ginkgo biloba extract (EGb 761) was investigated in UVB irradiated mice skin.

The effect of allopurinol on Na+K+ATPase related lipid peroxidation in ischemic and reperfused rabbit kidney

1. Na+K+ATPase is a membrane bound enzyme whose activity is essential for maintenance of cell viability. Lipid peroxidation changes membrane fluidity and enzyme activity. 2. The purpose of this study was to investigate the effect of allopurinol (free radical scavenger) on Na+K+ATPase activity in rabbit kidney cortex membrane. In this in vivo study we created ischemia and reperfusion in rabbit kidneys. 3. Enzyme activity were low in ischemic and reperfused kidneys, compared to the controls. In allopurinol treated ischemic and reperfused groups, the levels of Na+K+ATPase activity were high compared to the untreated group. 4. It has been concluded that allopurinol may protect this enzyme activity.

Effect of long term, non cholesterol lowering dose of fluvastatin treatment on oxidative stress in brain and peripheral tissues of streptozotocin-diabetic rats

One of the main goals of treatment of diabetes mellitus is to prevent its complications. Oxidative stress is universal in diabetes, being ultimately involved with the development complications. As a result of hyperglycemia, reactive oxygen/nitrogen species are produced in various tissues that leads to tissue damage with lipid peroxidation and protein oxidation, along with disruption in cellular homeostasis and accumulation of damaged molecules. Hence, supplementation with antioxidant compounds may offer some protection against diabetic complications. The pleiotropic effects of statins, including antioxidant and anti-inflammatory properties, represent an area of great interest in prevention and therapy of cardiovascular and neurological disorders. Using biomarkers of oxidative stress, in this study we examined the effect of non cholesterol lowering dose, long term fluvastatin treatment on oxidative stress in streptozotocin-diabetic rats. Experiments were conducted in 24 Wistar adult male rats. Diabetic and non-diabetic rats were treated orally for 6 months with fluvastatin (2mg/kg/day, p.o) starting one week after streptozotocin injection (55 mg/kg, i.p.), (preventive study). In brain, heart, liver, pancreas and kidney homogenates malondialdehyde, lipid hydroperoxide, protein carbonyl content, advanced oxidation protein products, 3-nitrotyrosine levels and superoxide dismutase, catalase activities were measured. Hyperglycemia and dyslipidemia in diabetic groups remained unchanged after fluvastatin treatment. The drug act as antioxidant in the tissues. Hence, antioxidant property of fluvastatin, independent of cholesterol lowering effect, may play a role in prevention of diabetic complications. Clinical relevance of this effect of fluvastatin seems worthy of further studies.

Taurine and calcium interaction in protection of myocardium exposed to ischemic reperfusion injury

We aimed to investigate the cardio-protective role of taurine with low calcium level against reperfusion damage by adding taurine to extracellular fluid. Guinea-pig hearts were mounted on Langendorf perfusion apparatus and different compositions of perfusion solutions were prepared for each experimental group. After 20 min of normothermic ischemia the hearts were reperfused. Pre-ischemic, post-ischemic and post-reperfusion percentage changes of heart rate and contractile force were compared. Post-reperfusion tissue weight, malondialdehyde (MDA) and prostaglandin E-like activity (PGE-like activity) were assessed. Taurine-added low-calcium perfusion solution significantly decreased the postischemic myocardial injury.

Changes in zinc levels and superoxide dismutase activities in the skin of acute, ultraviolet-B-irradiated mice after treatment with ginkgo biloba extract.

Acute ultraviolet-B (UV-B) irradiation is known to act as an initiator in the formation of reactive oxygen species. These oxygen products are highly reactive and they are able to cause irreversible damage to cellular components. Oxygen free radicals are normally neutralized by very efficient systems in the body. These include antioxidant enzymes like superoxide dismutase (SOD). In a healthy subject, there is a balance between free radicals and the levels of antioxidants. In some pathological conditions such as oxidative stress, the level of antioxidants is significantly reduced. The skin contains relatively high levels of zinc (Zn), an essential element known to be a cofactor in some metabolic pathways. Zinc has also been reported to have antioxidant properties.In the present study, we investigated the effect of ginkgo biloba extract (Gbe), a potent free-radical scavenger, on UV-B-irradiated skin by measuring SOD activity and Zn levels in the skin, before and after treatment. The SOD activity was decreased after UV-B exposure, in comparison with the control group (p<0.05). After Gbe treatment, the SOD activity increased (p<0.05) as compared with the untreated UV-B irradiated group. The Zn levels changed in the same pattern as the SOD activity values.

Investigation of ocular neovascularization-related genes and oxidative stress in diabetic rat eye tissues after resveratrol treatment.

Changes in vascular endothelial growth factor (VEGF), angiotensin-converting enzyme (ACE), matrix metalloproteinase (MMP)-9, and endothelial nitric oxide synthase (eNOS) mRNA expression profiles and oxidative stress in the eye tissue microenviroment may have important roles in ocular neovascularization and permeability in proliferative diabetic retinopathy. The present study investigated the effects of resveratrol (RSV) treatment on the mRNA expression profile of VEGF, ACE, MMP-9, and eNOS, which are associated with vascular neovascularization, and glutathione, protein carbonyl, and nitrite-nitrate levels, which are markers of oxidative stress in eyes of diabetic rats. Twenty-four Wistar albino male rats were divided into four groups. After diabetes induction with streptozotocin (10 mg/kg/day) RSV was administered to the RSV and diabetes mellitus (DM) + RSV groups for 4 weeks. The mRNA levels were measured by quantitative real-time polymerase chain reaction assay, and biochemical estimations were determined with spectrophotometric assays in eye homogenates. The mRNA expression levels of VEGF, ACE, and MMP-9 were increased in the DM group compared with the control group, and RSV treatment decreased their mRNA levels. Expression of eNOS mRNA was increased in the RSV and DM groups and decreased in the DM + RSV group. Nitrite-nitrate levels and protein carbonyl content were increased and glutathione levels were decreased in the DM group compared with controls. Consequently, these data suggest that RSV suppressed the expression of eNOS, which is actively involved in the inflammation and healing process in chronic diabetes. Although oxidative stress was increased in eye tissue from diabetic rats, mRNA levels of VEGF, MMP-9, and ACE genes associated with vascular remodeling did not change in diabetic eyes.

The effects of taurine on perfused heart muscle malondialdehyde levels

1. Taurine is found as a free amino acid in plasma and many tissues such as heart, muscle, brain and blood. Its exact role is not fully defined but it appears to have an important effect on the function of the heart. 2. The purpose of this study was to investigate the effects of taurine (10(-3) M and 10(-2) M) on malondialdehyde levels in perfused heart muscle. 3. In this study we found that administrated taurine before anoxia and reperfusion increased the malondialdehyde levels but administrated taurine after anoxia decreased the malondialdehyde levels in perfused heart muscle compared to the taurine administrated group before anoxia. 4. Anoxia did not change the perfused heart muscle malondialdehyde levels.

Renal Tissue Damage After Experimental Pyelonephritis: Role of Antioxidants and Selective Cyclooxygenase-2 Inhibitors

OBJECTIVES To investigate the involvement of oxidative stress in the pathogenesis of acute pyelonephritis, and to evaluate the impact of meloxicam and/or L-carnitine in addition to conventional antibiotic treatment. METHODS A total of 48 Wistar rats were divided into 4 groups according to their treatment, which was started 1 day after inoculation of all rats with Escherichia coli (ATCC 25 922, 10(10) cfu/mL). Group 1 received only antibiotic treatment with ceftriaxone (50 mg/kg, IM). Groups 2 and 3 received L-carnitine (500 mg/kg, IM) and meloxicam (3 mg/kg, IM) in addition to conventional treatment, respectively. Group 4 received combination therapy (L-carnitine and meloxicam) in addition to the first group. Rats were killed 3 and 7 days after E. coli inoculation and underwent nephrectomy. Histologic determination of tubular atrophy, acute and chronic inflammation, interstitial fibrosis and biochemical determination of superoxide dismutase and catalase activity, total thiol content, total antioxidant capacity, and malondialdehyde and protein hydroperoxide levels were measured. RESULTS Interstitial fibrosis (P = .06), chronic inflammation (P = .536), and tubular atrophy (P = 0.094) decreased in group 4 compared with the other groups, but there was a statistically significant decrease only in acute inflammation (P = .015). In addition, if the day of nephrectomy is considered, there was again a significant decrease in acute inflammation on day 7 compared with day 3 in groups 2, 3, and 4 (P = .002). Catalase significantly increased in group 2 (P = .029), group 3 (P = .02), and group 4 (P = .014), and decreased in group 1 (P = .012) in day 7. CONCLUSIONS L-carnitine and meloxicam alleviated oxidative stress, probably by decreasing lipid peroxidation and enforcing antioxidant defense system. Acute renal inflammatory injury can be prevented much more effectively by combination therapy rather than by conventional therapy alone.

Antioxidative role of ocular melanin pigment in the model of lens induced uveitis

Ocular melanin pigment has antioxidant effect against excess of dispersed light. To investigate whether it has a similar effect in ocular inflammations, we used albino and pigmented guinea pigs and measured retinal glutathione peroxidase activities and lipid peroxide levels (expressed as thiobarbituric acid reactive substances) in a model of lens induced uveitis. Although the increase in the levels of the retinal lipid peroxides were higher in the albino group (204%, p < 0.05), the decrease in the activities of glutathione peroxidase were higher in pigmented guinea pigs (26%, p < 0.005). The results of the study suggest that pigmentless animals are more sensitive to the ocular inflammations, and ocular melanin pigment may act as an endojen antioxidant in lens induced uveitis.

Effects of Radiation on Protein Oxidation and Lipid Peroxidation in the Brain Tissue

Radiation produces reactive oxygen species that modify macromolecules such as protein and lipid by oxidation and act in many pathological processes, causing serious damage to the brain. This study sought to evaluate the effects of radiation and the protective effect of N-acetylcysteine (NAC) on the brain tissue of guinea pigs based on the levels of lipid peroxidation and protein oxidation. Thirty-two guinea pigs were divided into groups of eight animals each: control group (group I); radiation group (group II); NAC group (group III), and NAC administered before radiation exposure group; (group IV). Guinea pigs in groups II and IV were exposed to Co(60) radiotherapy using the Source-Axis-Distance = 80 technique. The levels of protein carbonyl content and malondialdehyde (MDA), which is a marker for lipid peroxidation, were investigated by the Evans-Levine and Uchiyama-Mihara methods, respectively. The protein carbonyl and MDA levels of group II were significantly greater than those of group I (P < .01). The protein carbonyl and MDA levels of group IV were lower than those of group II. The difference between the MDA levels of group IV and group II was significant (P < .01); however, the difference in protein carbonyl levels between the two groups was not significant. The results indicated that radiation increased protein oxidation and lipid peroxidation in the brain, and NAC administration before radiation exposure may aid in the treatment by decreasing protein and lipid oxidation.