Browsing by Author "Altuner, Durdu"

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The Effect of Thiamine Pyrophosphate on Ethambutol-Induced Ocular Toxicity
(Taylor & Francis Ltd, 2016) Cinici, Emine; Cetin, Nihal; Ahiskali, Ibrahim; Suleyman, Bahadir; Altuner, Durdu; Alp, Hamit Hakan; Suleyman, Halis
Context: Ethambutol-induced retinal oxidative damage in patients with tuberculosis is still not being adequately treated. The protective effect of thiamine pyrophosphate against oxidative damage in some tissues has been reported, but no information on the protective effects of thiamine pyrophosphate against ethambutol-induced oxidative retinal damage has been found in the medical literature.Objective: The objective is to investigate whether thiamine pyrophosphate has a protective effect against oxidative retinal damage in rats induced by ethambutol.Materials and methods: Experimental animals divided into four groups (n=10): the healthy group (HG), the ethambutol control group (EMB), thiamine+ethambutol group (Thi-EMB) and thiamine pyrophosphate+ethambutol group (TPP-EMB). The rats in the TPP-EMB and Thi-EMB groups were administered thiamine pyrophosphate and thiamine, respectively, at doses of 20mg/kg intraperitoneally. Distilled water was administered intraperitoneally to the HG and the EMB groups as a solvent in the same volumes. One hour after drug injection, 30mg/kg ethambutol was administered via an oral gavage to the TPP-EMB, Thi-EMB and EMB groups. This procedure was repeated once a day for 90 days. At the end of this period, all rats were euthanized under high-dose thiopental sodium anesthesia, and biochemical and histopathological investigations of the retinal tissue were performed.Results: Malondialdehyde (MDA) and DNA damage product 8-hydroxyguanine levels were significantly lower in the retinal tissue of TPP-EMB and HG groups compared to those of the Thi-EMB and EMB groups, and total glutathione (tGSH) was also found to be higher. In addition, severe retinal tissue vascularization, edema and loss of ganglion cells were observed in the Thi-EMB and EMB groups, whereas histopathological findings for the TPP-EMB group were observed to be close to normal.Discussion and conclusion: These findings suggest that thiamine pyrophosphate protects retinal tissues from ethambutol-induced oxidative damage, and thiamine does not. This positive effect of thiamine pyrophosphate may be useful in the prevention of ocular toxicity that occurs during ethambutol use.
The Effects of Taxifolin on Neuropathy Related With Hyperglycemia and Neuropathic Pain in Rats: a Biochemical and Histopathological Evaluation
(Wroclaw Medical Univ, 2022) Alay, Murat; Sonmez, Miyase Gulcin; Sakin, Aysegul; Atmaca, Murat; Suleyman, Halis; Yazici, Gulce Naz; Altuner, Durdu
Background. Hyperglycemia can be considered a determining factor in the development of diabetic neuropathy as well as neuropathic pain. There is a relationship between the excessive production of reactive oxygen species (ROS) and the pathogenesis of diabetic neuropathic pain. Taxifolin, on the other hand, is a flavonoid that has been documented to inhibit ROS production. Objectives. To investigate the effects of taxifolin, which has antioxidant and neuroprotective effects, on alloxan-induced hyperglycemia-induced neuropathy and neuropathic pain, biochemically and histopathologically. Materials and methods. The albino Wistar male rats were divided into 3 groups: healthy group (HG), only alloxan group (AXG) and alloxan+taxifolin group (ATG). Hyperglycemia in animals was caused through intraperitoneal injection of alloxan at a dose of 120 mg/kg. Paw pain thresholds of animals were measured using Basile algesimeter. Sciatic nerve tissues were examined biochemically and histopathologically in order to evaluate neuropathy. Results. Our experimental results revealed that taxifolin significantly prevented the increase of plasma glucose concentration level with alloxan administration, the decrease of the paw pain threshold related to hyperglycemia, the change of oxidant-antioxidant balance in the sciatic nerve tissue in favor of oxidants, and the deterioration of tissue morphology in animals. Conclusions. Our experimental results indicate that taxifolin alleviates alloxan-induced hyperglycemiarelated neuropathy and neuropathic pain.
Favipiravir-Induced Inflammatory and Hydropic Degenerative Liver Injury in Rats
(Wroclaw Medical Univ, 2023) Bilici, Sami; Altuner, Durdu; Suleyman, Zeynep; Bulut, Seval; Sarigul, Cengiz; Gulaboglu, Mine; Suleyman, Halis
Background. Favipiravir is very effective in the treatment of many viral infections, especially at high doses. It was used at such doses to treat coronavirus disease 2019 (COVID-19) during the pandemic. However, liver damage was reported in patients undergoing such treatment. Objectives. This study aimed to investigate the effects of low and high doses of favipiravir on the liver of rats, using biochemical and histopathological methods. Materials and methods. Wistar albino rats were allocated to one of 3 groups, namely a healthy group (HG), a 100 mg/kg favipiravir (FAV-100) group and a 400 mg/kg favipiravir (FAV-400) group. Favipiravir was administered orally at 100 mg/kg and 400 mg/kg doses to the FAV-100 (n = 6) and FAV-400 (n = 6) groups, respectively. Distilled water was administered orally (1 mL) using the same method to the HG (n = 6). This procedure was repeated twice a day for 1 week. At the end of this period, the animals were euthanized with a high dose of thiopental anesthesia (50 mg/kg) and their liver tissues were removed. Results. Favipiravir caused an increase in malondialdehyde (MDA), nuclear factor kappa B (NF-kappa B) and interleukin 6 (IL-6) levels in the liver tissue, as well as elevated alanine aminotransaminase (ALT) and aspartate aminotransferase (AST) levels in the blood. Moreover, favipiravir caused a decrease in total glutathione (tGSH), superoxide dismutase (SOD) and catalase (CAT) levels. In addition, severe edema, lymphocyte infiltration and hydropic degeneration were observed in the liver tissue of the FAV-400. Conclusions. High-dose favipiravir caused more significant oxidative and inflammatory damage in the liver tissue of rats than low-dose favipiravir.
The Protective Effect of Melatonin and Agomelatin Against Cisplatin-Induced Nephrotoxicity and Oxidative Stress in the Rat Kidney
(Colegio Farmaceuticos Provincia de Buenos Aires, 2013) Yilmaz, Ismayil; Demiryilmaz, Ismail; Turan, Mehmet I.; Suleyman, Bahadir; Turan, Isil S.; Altuner, Durdu; Suleyman, Halis
Cisplatin is used to treat various types of cancers. Its use is limited, however, due to nephrotoxicity, which may result from free radical damage. Evidence exists that melatonin reduces oxidative stress-induced damage. This study investigated the protective effect of agomelatin, a melatonin receptor agonist, against cisplatin-induced nephrotoxicity and oxidative stress in the rat kidney. Groups of rats were given cisplatin with or without agomelatin or melatonin, or distilled water for 14 days. MDA, tGSH, MPO and 8-OH Gua levels were measured to determine oxidative and DNA damage in renal tissue. Levels of MDA, MPO and 8-OH Gua were lower in the Mel+Cis and Ago+Cis groups than in the Cis group (P < 0.001, P < 0.001, and P < 0.05, respectively). The tGSH level in the Mel+Cis group was higher than that in the Cis group (P < 0.001). Agomelatin and melatonin thus reduced cisplatin-induced oxidative damage and DNA damage in the rat kidney. This suggests that melatonin may be effective in preventing cisplatin nephrotoxicity.