Biomedical subjects

Mert Ozgönül

Publications and source records attributed to Mert Ozgönül.

3 recordsLinked to original sources

PubMed2003

The effects of estrogen and raloxifene treatment on the antioxidant enzymes and nitrite-nitrate levels in brain cortex of ovariectomized rats.

Number of studies indicate that the female gonadal hormone estrogen protects women against several neurodegenerative diseases and cerebral ischemia via various mechanisms. The possible protective effects of estrogen are mediated mainly by three ways; the activation of steroid receptors and/or modulation of a neurotransmitter and/or direct antioxidative action. Therefore we aimed to investigate the effects of estradiol and raloxifene on levels of nitric oxide (NO) and antioxidant enzymes in brain cortex of ovariectomized female rats. Ten Sprague-Dawley rats were used as naive controls while 32 rats were ovariectomized at 120-140 days of age. Twelve weeks after ovariectomy: (1). Ovariectomized Placebo group (n=11), was given physiologic saline. (2). Estrogen group (n=10) was given Ethynyl estradiol, 0.1 mg/kg sc. (3). Raloxifene group (n=10) was given raloxifene, 1 mg/kg sc. At the end of the treatment period (8 weeks), rats were decapitated and cortex samples were dissected. Results showed that ovariectomy caused a decrease in total nitrite-nitrate levels. The NO levels of both the estrogen and the raloxifene group were higher than the placebo group. Catalase activities did not show any significant difference between the groups, while superoxide dismutase (SOD) activities were elevated via ovariectomy. Estradiol and Raloxifene treatment had no statistically significant effect on SOD activity.

Animals↗

PubMed2003

The effects of estrogen and raloxifene treatment on antioxidant enzymes in brain and liver of ovarectomized female rats.

Recent studies documented that estrogen have antioxidant properties in-vitro, there are conflicting results on the effect of estrogen in vivo. We aimed to investigate the effects of estradiol and Raloxifene on the antioxidant enzyme [superoxide dismutase (SOD) and catalase (CAT)] activities and MDA levels in brain and liver homogenates of ovariectomized female rats. Twelve weeks after ovariectomy, female Sprague-Dawley rats (n = 26) were divided into three groups: (1) Ovariectomized placebo group (n = 6) was given physiologic saline. (2) Estrogen group (n = 10) was given Ethynyl estradiol, 0.1 mg/kg sc. (3) Raloxifene group (n = 10) was given raloxifene, 1 mg/kg sc during 8 weeks. Ten rats were used as naive controls without any treatment (Sham operated group, n = 10). Ovariectomy lead to an increase in the CAT activities in liver tissue samples compared to the sham group (p = 0.056, Mann-Whitney test). While estrogen treatment reversed to normal levels of CAT activities, raloxifene remained as ineffective. Superoxide dismutase activities and MDA levels in liver were remained unchanged in all groups. There was no significant change in the brain tissue SOD and CAT activities between the control ovariectomy, estrogen treated, and raloxifen treated groups. We determined an increase in MDA levels in brain of ovariectmised rat (p = 0.02). While raloxifene treatment reversed to normal levels of MDA (p = estrogen treatment failed. Our data showed that estrogen may play a role in regulation of CAT and SOD activities in liver due to its antioxidative effects. We can suggest estrogen and raloxifene exert their antioxidative effects in brain rather than liver. Since Raloxifene's effect is more clear than estradiol, raloxifene may be suggested primarily for treatment and/or prevention of diseases which can be resulted from oxidative stress in postmenopausal women.

Analysis of Variance↗

PubMedDate not supplied

Renal cortical thickness and PON1 activity both decrease in chronic renal failure.

BACKGROUND: Chronic renal failure (CRF) is associated with a tendency to atherosclerosis due to the enhanced oxidative stress and insufficient antioxidant enzyme activities such as superoxide dismutase (SOD), catalase (CAT) and paraoxonase (PON 1), together with abnormalities in lipid parameters. We determined the in vitro susceptibility of low-density lipoprotein (LDL) to oxidation and PON1 activities in patients with chronic renal insufficiency to see how PON1 affected the progression of the disease and whether hemodialysis influenced these parameters. METHODS: Thirty-seven patients (21 men, 16 women, mean age 43.9 +/- 16) with CRF were included, 23 were receiving hemodialysis treatment. Exclusion criteria were diabetes mellitus and acute coronary disease. Eighteen healthy subjects (9 men and 9 women, mean age 39.9 +/- 10.5) volunteered to participate as controls. All patients were evaluated by renal ultrasound (USG) and two-dimensional echography, and their lipid profiles, PON1 activity, basal and Cu-induced LDL oxidation were determined. RESULTS: PON1 activities of patients were lower than controls (14.4 +/- 11 vs 30.9 +/- 19 U/L, p < 0.05) while basal ox-LDL levels determined by the thiobarbituric acid reactive substances (TBARS) method were higher (0.6 +/- 0.4 vs 0.4+/- 0.2 nmol/mg LDL protein, p<0.01). There was no significant difference between the groups treated with hemodialysis or not. There was a positive correlation between renal cortical thickness and HDL levels (r=0.47, p=0.006) and PON1 activity (r=0.45, p=0.01). CONCLUSION: Our data showed that HDL cholesterol levels and PON1 activities were both lower in patients, indicating depletion of the protective antioxidant capacity. PON1 activities and phenotypes were no different in patients with coronary disease and others so it does not appear to be a significant indicator of coronary artery disease in patients with CRF.

Adult↗