Person: YEGEN, BERRAK
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YEGEN
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BERRAK
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Publication Metadata only The antifibrotic drug halofuginone reduces ischemia/reperfusion-induced oxidative renal damage in rats(ELSEVIER SCI LTD, 2013) YEGEN, BERRAK; Cerit, Kivilcim Karadeniz; Karakoyun, Berna; Yuksel, Meral; Ozkan, Naziye; Cetinel, Sule; Dagli, E. Tolga; Yegen, Berrak C.; Tugtepe, HalilAim: The objective of the present study was to evaluate the protective effects of halofuginone against renal ischemia/reperfusion (I/R) injury. Materials and methods: Male Wistar albino rats were unilaterally nephrectomized and the left renal pedicles were occluded for 45 min to induce ischemia and then reperfused for 6 h (early) or for 72 h (late). The rats were treated intraperitoneally with either halofuginone (100 mu g/kg/day) or saline 30 min prior to ischemia and the dose was repeated in the late reperfusion groups. In the sham groups, rats underwent unilateral nephrectomy and were treated at similar time points. The animals were decapitated at either 6 h or 72 h of reperfusion and trunk blood and kidney samples were obtained. Results: I/R injury increased renal malondialdehyde levels, myeloperoxidase activity and reactive oxygen radical levels, and decreased the renal glutathione content. Halofuginone treatment was found to reduce oxidative I/R injury and improve renal function in the rat kidney, as evidenced by reduced generation of reactive oxygen species, depressed lipid peroxidation and myeloperoxidase activity, and increased glutathione levels. Conclusions: The present findings demonstrate the anti-inflammatory and antioxidant effects of halofuginone in renal I/R injury, supporting its potential use where renal I/R injury is inevitable. (C) 2012 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.Publication Metadata only Melatonin supports alendronate in preserving bone matrix and prevents gastric inflammation in ovariectomized rats(WILEY, 2019) YEGEN, BERRAK; Gurler, Esra Bihter; Cilingir-Kaya, Ozlem Tugce; Eyuboglu, Irem Peker; Ercan, Feriha; Akkiprik, Mustafa; Reiter, Russell J.; Yegen, Berrak C.The anti-catabolic bisphosphonate alendronate is considered as the first-line medical treatment in post-menopausal osteoporosis; but several side effects, including gastric mucosal injury, are associated with its use. The aim was to elucidate whether combined treatment with melatonin plus alendronate would be more advantageous in the maintenance of bone and the prevention of gastric side effects. Under anaesthesia, female Sprague-Dawley rats underwent bilateral ovariectomy (OVX), while control group had sham surgery. Four weeks after the surgery, OVX rats were treated with saline, melatonin (25 mu g/mL/d), alendronate (70 mu g/kg/wk), melatonin + alendronate, melatonin + melatonin receptor antagonist (luzindole, 10 mu g/kg/d) or alendronate + melatonin + luzindole for 8 weeks. Rats were euthanized at the end of 12th week. Runx2 expression, apoptotic cells, and trabecular thickness were evaluated in tibiae, while gastric tissues were analysed for oxidative injury parameters. In all OVX groups, Runx2 expression was depressed. Saline-treated OVX group presented an extreme decrease in calcified area in opposition to melatonin- or alendronate-treated groups, while the bones in alendronate + melatonin-treated group were similar to those of the sham-operated group. Concomitant with the improvements examined histologically in bone tissues, quantitative TUNEL (+) cells were similarly lower in alendronate- or melatonin-treated groups. Oxidative gastric damage was increased in saline- or alendronate-treated groups, which were depressed in the presence of melatonin. Although melatonin and alendronate exerted similar supportive effects on the maintenance of bone mass, melatonin may have a more advantageous impact by protecting against OVX-induced gastric injury, which was aggravated by alendronate use. Highlights Our results demonstrate that alendronate and melatonin had similar supportive effects on the maintenance of bone mass, while melatonin prevented the gastric side effects of alendronate, making this combination an advisable therapeutic approach in the treatment of menopausal osteoporosis.Publication Metadata only The neuroprotective and anti-apoptotic effects of melatonin on hemolytic hyperbilirubinemia-induced oxidative brain damage(WILEY, 2016) MEMİŞOĞLU, ASLI; Pazar, Asilay; Kolgazi, Meltem; Memisoglu, Asli; Bahadir, Elif; Sirvanci, Serap; Yaman, Akan; Yegen, Berrak C.; Ozek, ErenMelatonin exerts protection in several inflammatory and neurodegenerative disorders. To investigate the neuroprotective effects of melatonin in an experimental hemolysis-induced hyperbilirubinemia, newborn Sprague-Dawley rats (25-40 g, n = 72) were injected with phenylhydrazine hydrochloride (PHZ; 75 mg/kg) and the injections were repeated at the 24th hour. Rats were treated with saline or melatonin (10 mg/kg) 30 min before the first and second PHZ injections and 24 h after the 2nd PHZ injections. Control rats (n = 24) were injected with saline, but not PHZ. At sixth hours after the last injections of saline or melatonin, all rats were decapitated. Tumor necrosis factor (TNF)-alpha, IL-1 beta, IL-10 and brain-derived neurotrophic factor (BDNF) and S100B levels in the plasma were measured. Brain tissue malondialdehyde (MDA), glutathione (GSH) levels and myeloperoxidase (MPO) activities were measured, and brain tissues were evaluated for apoptosis by TUNEL method. In the saline-treated PHZ group, hemoglobin, hematocrit levels were reduced, and total/direct bilirubin levels were elevated when compared to control group. Increased plasma TNF-alpha, IL-1 beta levels, along with decreased BDNF, S100B and IL-10 values were observed in the saline-treated PHZ group, while these changes were all reversed in the melatonin-treated group. Increased MDA levels and MPO activities in the brain tissues of saline-treated hyperbilirubinemic rats, concomitant with depleted brain GSH stores, were also reversed in the melatonin-treated hyperbilirubinemic rats. Increased TUNEL(+) cells in the hippocampus of saline-treated PHZ group were reduced by melatonin treatment. Melatonin exerts neuroprotective and anti-apoptotic effects on the oxidative neuronal damage of the newborn rats with hemolysis and hyperbilirubinemia.Publication Metadata only Deneysel sepsis modelinde akut kardiyopulmoner ve serebral hasarda nöropeptit W'nin etkisi(2019-12-13) ATICI, ALİ EMRE; PEKER EYÜBOĞLU, İREM; YEGEN, BERRAK; AKKİPRİK, MUSTAFA; ERCAN, FERİHA; ATICI A. E., ARABACI TAMER S., levent h. n., PEKER EYÜBOĞLU İ., ERCAN F., AKKİPRİK M., YEGEN B.Giriş ve Amaç: Ciddi enfeksiyonların neden olduğu sepsis ve beraberinde görülen çoklu organ yetmezliği, yüksek morbidite ve mortalite oranıyla en önemli klinik sendromlardan biridir. Yakın zamanda tanımlanan ve nöroendokrin düzenlemelerde işlev gördüğü gösterilen nöropeptit W (NPW)’nin, deneysel sepsis modeli oluşturularak akciğer, kalp ve beyin dokularında indüklenen oksidatif hasarda olası tedavi edici etkilerini araştırmayı amaçladık. Yöntemler: Ketamin anestezisi altında, Sprague-Dawley erkek sıçanlarda sham-operasyon (n=8) yapıldı veya çekal ligasyon ve perforasyon ile sepsis oluşturuldu (n=64). Post-operatif ciltaltına 3 doz (hemen sonra, 12. ve 24. saatlerde) serum fizyolojik (SF) veya TNF-alfa inhibitörü + antibiyotik (1 mg/kg etanersept + 100 mg/kg seftriakson) veya NPW (0,1; 0,3; 1, 3 ve 10 g/kg) uygulanırken, sham-opere gruba SF enjeksiyonları yapıldı. Yirmibeşinci saatte alınan kan örneklerinde C-reaktif protein (CRP), kortikosteron ve IL-6 düzeyleri ile çıkarılan akciğer, kalp ve beyin dokularında antioksidan glutatyon, lipit peroksidasyonunu gösteren malondialdehit ile nükleer faktör kappa-B (NF- B) mRNA ekspresyon düzeyleri ölçüldü. Hematoksilen-eozin ile histopatolojik değerlendirmeler yapıldı. Verilerin analizinde ANOVA ve Student’ın t-testleri kullanıldı. Bulgular: Etanersept+antibiyotik veya NPW (1-10 g/kg) tedavili sepsis gruplarında IL6, kortikosteron ve CRP düzeyleri SF-tedavili sepsis grubuna göre düşük bulundu (p<0,05-0,001). SFsepsis grubunda beyinde ve akciğerde malondialdehit düzeylerinin arttığı (p<0,01) ve glutatyonun düştüğü (p<0,01) gözlendi. Etanersept+antibiyotik tedavisi veya NPW beyindeki bu değişiklikleri engelledi (p<0,05-0,001). Buna karşın, akciğerde sepsisle artan malondialdehit ve azalan glutatyon düzeylerine antibiyotik+etanersept etkili olmazken, NPW (0,1-0,3 g/kg) akciğerde malondialdehit düzeyini düşürdü (p<0,05-0,01). Kalp dokusunda ölçülen malondialdehit ve glutatyon düzeyleri ile tüm dokularda ölçülen NF- B ekspresyonları açısından gruplar arasında anlamlı fark bulunmadı. SF-tedavili sepsis grubunda gözlenen dejenere nöron sayısında artış, akciğerde şiddetli kanama, alveoler yapıda bozulma ve nötrofil infiltrasyonu ile kardiyomiyositlerdeki konjesyon ve orta derecede hasar gibi değişikliklerin etanersept+antibiyotik ve NPW (10 g/kg) ile hafiflediği ve histolojik yapıların neredeyse normale döndüğü izlendi. Sonuç: Sepsisin ilk 24 saatinde uygulanan NPW, doza bağımlı olarak akciğer ve beyinde oksidatif hasara karşı koruyucu etki göstermektedir.Publication Metadata only The effect of betulinic acid on TNBS-induced experimental colitis [Betulinik asitin TNBS ile oluşturulan deneysel kolit üzerine etkileri](2013) YEGEN, BERRAK; Şener T.E., Kardaş R.C., Şehirli A.Ö., Ekşioǧlu-Demiral E., Yüksel M., Çetinel Ş., Yeǧen B.C., Şener G.In this study we have investigated the possible protective effect of betulinic acid (BA) on colonic inflammation in rats. Colitis was induced in Sprague-Dawley rats of both sexes by intracolonic administration of 1 ml trinitrobenzene sulphonic acid (TNBS). Colitisinduced rats received orogastrically either betulinic acid (50 mg/kg/day) or vehicle (0.05% DMSO) for 3 days. At the 72nd hour of colitis induction, the rats were decapitated and trunk blood was collected for the measurement of TNF-α, IL-1Β, lactate dehydrogenase (LDH) levels and total antioxidant capacity (AOC). The distal 8 cm of colon were scored macroscopically, and the degree of oxidant damage was evaluated by malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase activity (MPO), collagen content and by histological analysis. Generation of oxidants was evaluated by tissue luminol and lucigenin chemiluminescences (CL). Colitis caused significant increases in the colonic CL values, macroscopic damage scores, MDA, MPO and collagen levels, along with a significant decrease in tissue GSH level. Similarly, serum TNF-α, IL-1Β, as well as LDH were elevated and AOC was reduced in the vehicle-treated colitis group as compared to control group. On the other hand, betulinic acid treatment reversed all these biochemical indices, as well as histopathological alterations induced by TNBS, suggesting that betulinic acid protects the colonic tissue via its radical scavenging and antioxidant activities.Publication Open Access Protective and Therapeutic Effects of Polygonum cognatum Meissn Aqueous Extract in Experimental Colitis(2014-09-08) YARAT, AYŞENPublication Metadata only Role of Melatonin and Luzindole in Rat Mammary Cancer(TAYLOR & FRANCIS INC, 2012) YEGEN, BERRAK; Umit, Ugurlu M.; Berna, Terzioglu; Handan, Kaya; Ipek, Erbarut; Berrak, Yegen; Can, Erzik; Bahadir, Gulluoglu M.Background: Recent studies have analyzed the efficacy of various agents in experimental chemoprevention trials. In our study, the effects of melatonin (Mel) and its antagonist Luzindole (Luz) on Heme oxygenase-1 (HO-1) in a NMU (N-methyl-N-nitrosourea)-induced rat mammary carcinoma model are investigated. We aim to demonstrate the relationship between Mel and HO-1. Methods: Spraque-Dawley rats were treated with NMU at age 55 days to induce mammary carcinoma. Forty-eight rats were divided into four groups consisting of: (a) physiological saline group (PSG); (b) control group, NMU is given; (c) Mel group (500 mu g daily); (d) Mel antagonist Luz group (0.25 mg/kg/day i.p.). The animals were sacrificed; their serum and tissues were sampled for histopathologic evaluation, markers of endocrine derangement (serum prolactin, estradiol, and progesterone levels), apoptotic changes, DNA fragmentation, markers of oxidative stress and HO-1 immune expression were measured. Results: Most tumors developed in the Luz group (42%), followed by the control group (33%), and the Mel group (17%). The tumor latency was longer in Mel-treated group (control and Luz at week 17, Mel at week 21). The maximum tumor volume was also smaller in Mel group when compared to control and Luz groups (p < .05). In Mel group estradiol, progesterone, and prolactin levels were decreased compared to control group (p < .001; p < .01; and p < .01) and levels of apoptotic activity and DNA fragmentation ratio increased. Conclusions: The increment of HO-1 expression with Mel is described; possible underlying mechanisms of these effects await further investigations.Publication Metadata only Neuroprotective Effect of Erythropoietin on PhenylhydrazineInduced Hemolytic Hyperbilirubinemia in Neonatal Rats(SPRINGER/PLENUM PUBLISHERS, 2017) MEMİŞOĞLU, ASLI; Memisoglu, Asli; Kolgazi, Meltem; Yaman, Akan; Bahadir, Elif; Sirvanci, Serap; Yegen, Berrak C.; Ozek, ErenNeonatal unconjugated hyperbilirubinemia might cause severe bilirubin neurotoxicity in especially hemolytic conditions. The study aimed to elucidate the potential neuroprotective effects of erythropoietin (EPO) in hemolysis-induced hyperbilirubinemia. In newborn rats, hyperbilirubinemia secondary to hemolysis was induced by injecting with phenylhydrazine hydrochloride (PHZ) and rats were injected with either vehicle or EPO. At 54th hour of the PHZ injection, rats were decapitated. Serum levels of TNF-alpha, IL-1 beta, IL-10, brain-derived neurotrophic factor (BDNF) and S100-B and brain malondialdehyde, glutathione levels and myeloperoxidase activities were measured. TUNEL staining and NF-kappa B expression were evaluated. As compared to control pups, in vehicle-treated PHZ group, TNF-alpha and IL- 1 beta levels, malondialdehyde level and myeloperoxidase activity were increased with concomitant decreases in IL-10 and glutathione. All EPO regimens reversed PHZ-induced alterations in IL-10, TNFa, malondialdehyde and glutathione levels. Three-daytreatment abolished increases in myeloperoxidase activity and IL-1 beta levels, while BDNF and S100-B were elevated. Increased TUNEL (+) cells and NF-kappa B expressions in the brain of PHZ group were reduced in the 3-day-treated group. EPO exerted anti- inflammatory effects on PHZinduced neural damage in newborn rats, while the neuroprotection was more obvious when the treatments were repeated successively. The results suggest that EPO treatment may have a therapeutic potential in supporting neuroplasticity in the hyperbilirubinemic neonates.Publication Metadata only Role of Ovarian Hormones in Psychological Stress-induced Oxidative Organ Damage in Rats(AVES PRESS LTD, 2016) YEGEN, BERRAK; Memi, Gulsun; Yegen, Berrak C.Objective: Stress response varies with respect to gender via the hypothalamic-pituitary-gonadal axis. We aimed to investigate the effect of ovarian hormone deficiency on psychological stress response and oxidative damage. Methods: Female Sprague Dawley rats (250-300 g, n=56) were divided as control, sham, and ovariectomy (OVX) groups. Sham operation or surgical OVX were conducted under anesthesia. After 60 days, the rats were placed in a special chamber to induce psychological stress by electric shock and were kept in the same chamber for 30 min on the following 3 days. Glucocorticoid receptor antagonist RU-486 (10 mg/kg), oxytocin receptor antagonist atosiban (1 mg/kg), or saline was intraperitoneally administered 10 min before stress exposure. After the hole-board anxiety test, the rats were decapitated on the 4th day; tissue and blood samples were obtained. Results: Psychological stress increased cortisol levels in the RU-486-administered group, while cortisol levels were decreased in the atosiban-administered group. Serum interleukin (IL)-1 ss levels, but not TNF-alpha levels, were increased by inducing stress. Stress increased oxidative damage in the stomach, colon, and brain of ovariectomized rats (p<0.05-0.001), while atosiban partially reversed and RU-486 exaggerated oxidative damage. GSH levels that were depleted because of stress were partially replenished by administering atosiban; however, RU-486 had no effect on GSH levels. Conclusion: Although the absence of ovarian hormones during psychological stress had no effect on cortisol or anxiety levels, changes in cytokine levels and oxidative tissue damage were observed.Publication Metadata only Obestatin improves ischemia/reperfusion-induced renal injury in rats via its antioxidant and anti-apoptotic effects: Role of the nitric oxide(ELSEVIER SCIENCE INC, 2014) YEGEN, BERRAK; Koc, Mehmet; Kumral, Zarife Nigar Ozdemir; Ozkan, Naziye; Memi, Gulsun; Kacar, Omer; Bilsel, Serpil; Cetinel, Sule; Yegen, Berrak C.Obestatin was shown to have anti-inflammatory effects in several inflammatory models. To elucidate the potential renoprotective effects of obestatin, renal I/R injury was induced in male Sprague Dawley rats by placing a clamp across left renal artery for 60 min following a right nephrectomy. Clamp was released and the rats were injected with either saline or obestatin (10, 30, 100 mu g/kg). In some experiments, obestatin (10 mu g/kg) was administered with L-NAME (10 mg/kg) or L-Nil (0.36 mg/kg). Following a 24-h reperfusion, the rats were decapitated to measure serum creatinine and nitrite/nitrate levels, renal malondialdehyde (MDA), glutathione (GSH) levels and myeloperoxidase (MPO) activity and to assess cortical necrosis and apoptosis scores. Obestatin treatment reduced I/R-induced increase in creatinine levels, renal MPO activity and renal MDA levels, while renal GSH levels were significantly increased by obestatin. Histological analysis revealed that severe I/R injury and high apoptosis score in the kidney samples of saline-treated rats were significantly reduced and the cortical/medullary injury was ameliorated by obestatin. Expression of eNOS, which was increased by I/R injury, was further increased by obestatin, while serum NO levels were significantly decreased. iNOS inhibitor L-Nil reduced oxidative renal damage and improved the functional and histopathological parameters. I/R-induced elevation in eNOS expression, which was further increased by obestatin, was depressed by L-NAME and L-Nil treatments. The present data demonstrate that obestatin ameliorates renal I/R-injury by its possible anti-oxidative, anti-inflammatory and anti-apoptotic properties, which appear to involve the suppression of neutrophil accumulation and modulation of NO metabolism. (C) 2014 Elsevier Inc. All rights reserved.