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VELİOĞLU ÖĞÜNÇ, AYLİZ

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VELİOĞLU ÖĞÜNÇ

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AYLİZ

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  • PublicationOpen Access
    Propylthiouracil-induced hypothyroidism protects ionizing radiation-induced multiple organ damage in rats
    (BIOSCIENTIFICA LTD, 2006-05) VELİOĞLU ÖĞÜNÇ, AYLİZ; Sener, G.; Kabasakal, L.; Atasoy, B. M.; Erzik, C.; Velioglu-Ogunc, A.; Cetinel, S.; Contuk, G.; Gedik, N.; Yegen, B. C.
    The objective of this study was to examine the potential radioprotective properties of propylthiouracil (PTU)-induced hypothyroidism against oxidative organ damage induced by irradiation. Sprague-Dawley rats were pre-treated with saline or PTU (10 mg/kg i.p.) for 15 days, and were then exposed to whole-body irradiation (800 cGy). A group of rats were decapitated at 6 h after exposure to irradiation, while another group was followed for 72 h after irradiation, during which saline or PTU injections were repeated once daily. Lung, liver, kidney and ileum samples were obtained for the determination of malondialdehyde (MDA; an index of lipid peroxidation) and glutathione (GSH, an antioxidant) levels, myeloperoxidase activity (MPO; an index of tissue neutrophil accumulation) and collagen contents, while oxidant-induced DNA fragmentation was evaluated in the ileal tissues. All tissues were also examined microscopically and assayed for the production of reactive oxidants using chemiluminescence (CL). Lactate dehydrogenase (LDH), an indicator of tissue damage, and turnout necrosis factor-alpha (TNF alpha) were assayed in serum samples. Irradiation caused a significant decrease in GSH level, which was accompanied by significant increases in MDA levels, MPO activity, CL levels and collagen content of the tissues studied (P < 0.05-0.001). Similarly, serum TNFa and LDH were elevated in the irradiated rats as compared with the control group. On the other hand, PTU treatment reversed all these biochemical indices, as well as histopathological alterations induced by irradiation. Our results suggested that PTU-induced hypothyroidism reduces oxidative damage in the lung, hepatic, renal and ileal tissues probably due to hypometabolism, which is associated with decreased production of reactive oxygen metabolites and enhancement of antioxidant mechanisms.
  • PublicationOpen Access
    The Influence of N-Acetylcysteine Alone and in Combination with Angiotensin Converting Enzyme Inhibitor and Angiotensin Receptor Antagonist on Systemic and Tissue Levels in Rats with Experimentally-Induced Chronic Renal Failure
    (ZOOLOGICAL SOC PAKISTAN, 2020) VELİOĞLU ÖĞÜNÇ, AYLİZ; Sehirli, Ahmet Ozer; Sayiner, Serkan; Velioglu-Ogunc, Ayliz; Serakinci, Nedime; Eksioglu-Demiralp, Emel; Yegen, Berrak; Ercan, Feriha; Sener, Goksel
    The protective effects of ACE inhibitor, Captopril, and angiotensin receptor blocker, Valsartan, were evaluated in the treatment of chronic renal failure (CRF) with and without the presence of N-acetylcysteine (NAC). The renal mass of Wistar albino rats was reduced at a rate of 5/6. Captopril, Valsartan and NAC were applied intra-peritoneal alone or in combination. Blood pressure and heart rate were monitored at weekly intervals over a period of six weeks. Serum creatinine, blood urea nitrogen (BUN), lactate dehydrogenase (LDH) activity, cytokines (TNF-alpha, IL-1 beta, IL-6) concentrations, urinary volume, creatinine, and both serum and urinary electrolyte levels were measured. In addition, the apoptosis rate of white blood cells was analysed from plasma samples. Tissue samples from the brain, heart, aorta and kidneys were used for analysis of the collagen content besides tissue luminol, lucigenin, malondialdehyde (MDA) and glutathione (GSH) levels. A significant difference was determined between the CRF group and the control group with regard to heart rate, blood pressure, serum creatinine, BUN, LDH, cytokines and urinary electrolyte levels. Furthermore, monocyte and neutrophil apoptosis, tissue luminol, lucigenin, malondialdehyde and collagen levels were found to increase. Tissue glutathione levels were found to decrease indicating oxidative damage. These results indicate that oxidative mechanisms induce tissue damage in CRF, and the angiotensin receptor blocker, Valsartan, improved oxidative tissue damage when used in combination with the ACE inhibitor, Captopril or NAC, yielded better results and could be a novel approach for the treatment of CRF when used in combination with anti-oxidants.
  • PublicationOpen Access
    Neuroprotective Effects of Alpha-Lipoic Acid in Experimental Spinal Cord Injury in Rats
    (TAYLOR & FRANCIS LTD, 2010-01) VELİOĞLU ÖĞÜNÇ, AYLİZ; Toklu, Hale Z.; Hakan, Tayfun; Celik, Hasan; Biber, Necat; Erzik, Can; Ogunc, Ayliz V.; Akakin, Dilek; Cikler, Esra; Cetinel, Sule; Ersahin, Mehmet; Sener, Goksel
    Background: Oxidative stress is a mediator of secondary injury to the spinal cord following trauma. Objective: To investigate the putative neuroprotective effect of a-lipoic acid (LA), a powerful antioxidant, in a rat model of spinal cord injury (SCI). Methods: Wistar albino rats were divided as control, vehicle-treated SCI, and LA-treated SCI groups. To induce SCI, a standard weight-drop method that induced a moderately severe injury (100 g/cm force) at T10 was used. Injured animals were given either 50 mg/kg LA or saline at 30 minutes postinjury by intraperitoneal injection. At 7 days postinjury, neurologic examination was performed, and rats were decapitated. Spinal cord samples were taken for histologic examination or determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity, and DNA fragmentation. Formation of reactive oxygen species in spinal cord tissue samples was monitored by using a chemiluminescence (CL) technique. Results: SCI caused a significant decrease in spinal cord GSH content, which was accompanied with significant increases in luminol CL and MDA levels, MPO activity, and DNA damage. Furthermore, LA treatment reversed all these biochemical parameters as well as SO-induced histopathologic alterations. Conversely, impairment of the neurologic function caused by SCI remained unchanged. Conclusion: The present study suggests that LA reduces SCI-induced oxidative stress and exerts neuroprotection by inhibiting lipid peroxidation, glutathione depletion, and DNA fragmentation.