Person: KAYA, ÖZLEM TUĞÇE
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KAYA
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ÖZLEM TUĞÇE
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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 Open Access Ghrelin Treatment Improves Lipid Metabolism and Hepatic Degeneration in Ovariectomized Rats(GAZI UNIV, FAC MED, 2020-01-01) YEGEN, BERRAK; Gurler, Esra Bihter; Ozbeyli, Dilek; Kaya, Ozlem Tugce Cilingir; Ercan, Feriha; Yegen, Berrak C.Objective: Metabolic disorders occurring in post-menopausal period increase the risk for development of fatty liver disease in women. Aim of the study was to evaluate possible effects of ghrelin on metabolic biomarkers and hepatic morphology in ovariectomized (OVT) rats. Methods:Under ketamine-chlorpromazine anesthesia (100 mg/kg, 0.75 mg/kg), Sprague-Dawley rats (n=12) underwent bilateral OVT, while control group had sham-surgery (n=6). Four weeks after surgery, half of OVT rats were treated intraperitonally with ghrelin (1 mg/kg/hafta) for 4 weeks, while others were not treated. Rats were euthanized by cardiac puncture at the end of 8th weeks, and serum levels of glucose, insulin, aspartate aminotransferase (AST), high-density lipoprotein (HDL), low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), triglycerides, estradiol and progesterone were measured by an automated analyzer. Results: Increased body weights in OVT rats (p<0.001) recorded at the end of 2 months was not changed with ghrelin. Serum estradiol and progesterone levels were reduced (p<0.05) verifying altered gonadal hormone status, but insulin and glucose levels were not changed. Reduced HDL and increased LDL levels (p<0.0.5) were evident in non-treated OVX rats, while ghrelin treatment depressed LDL levels (p<0.0.5), but did not change HDL levels. However, ghrelin in OVT rats depressed triglycerides, VLDL and AST levels significantly (p<0.05). Moderate sinusoidal congestion, activated Kupffer cells and hepatocytes with ballooning degeneration was observed in non-treated OVT rats, while significant improvements were present in livers of ghrelin-treated rats. Conclusion: In conclusion, mild dyslipidemia and hepatic degeneration in early post-menopausal period appear to be attenuated by ghrelin treatment, and require further investigation.Publication Metadata only Nesfatin-1 treatment preserves antioxidant status and attenuates renal fibrosis in rats with unilateral ureteral obstruction(2022-06-01) ÇETİNEL, ŞULE; YEGEN, BERRAK; KAYA, ÖZLEM TUĞÇE; ÖZBEYLİ, DİLEK; Tezcan N., Özdemir-Kumral Z. N., Yenal N. Ö., Çilingir-Kaya Ö. T., Virlan A. T., Özbeyli D., Çetinel Ş., Yeğen B., Koç M.Background Nesfatin-1 (NES-1), an anorexigenic peptide, was reported to have anti-inflammatory and anti-apoptotic actions in several inflammation models. Methods To elucidate potential renoprotective effects of NES-1, unilateral ureteral obstruction (UUO) was induced in male Sprague Dawley rats by ligating left ureters. The rats were injected intraperitoneally with either saline (SL) or NES-1 (10 mu g/kg/day) for 7 or 14 days (n = 8 in each group). On the 7th or 14th day, obstructed kidneys were removed for the isolation of leucocytes for flow-cytometric analysis and the assessments of biochemical and histopathological changes. Results Opposite to glutathione levels, renal myeloperoxidase activity in the SL-treated UUO group was significantly increased compared with the sham-operated group, while NES-1 treatment abolished the elevation. The percentages of CD8+/CD4+ T-lymphocytes infiltrating the obstructed kidneys were increased in the SL-treated groups but treatment with NES-1 did not prevent lymphocyte infiltration. Elevated tumour necrosis factor-alpha (TNF-alpha) levels in SL-treated UUO group were decreased with NES-1. Although total degeneration scores were similarly increased in all UUO groups, tubular dilatation scores were significantly increased in UUO groups and lowered by NES-1 only in the 7-day treated group. Elevated interstitial fibrosis scores in the SL-treated groups were decreased in both 7- and 14-day NES-1 treated groups, while alpha-smooth muscle actin (alpha-SMA) and apoptosis scores were depressed in both NES-1 treated groups. Conclusion The present data demonstrate that UUO-induced renal fibrosis is ameliorated by NES-1, which appears to involve the inhibition of neutrophil infiltration and thereby amelioration of oxidative stress and inflammation. These data suggest that NES-1 may have a regulatory role in protecting the kidneys against obstruction-induced renal injury.Publication Open Access High-fat Diet Enhances Gastric Contractility, but Abolishes Nesfatin-1-induced Inhibition of Gastric Emptying(KOREAN SOC NEUROGASTROENTEROLOGY & MOTILITY, 2021-04-30) YEGEN, BERRAK; Ozdemir-Kumral, Zarife N.; Koyuncuoglu, Turkan; Arabaci-Tamer, Sevil; Cilingir-Kaya, Ozlem T.; Koroglu, Ayca K.; Yuksel, Meral; Yegen, Berrak C.Neither HFD nor NES-1 changed methylcellulose emptying, but NES-1 delayed saline emptying in cannulated ND-rats. Inhibitory effect of NES-1 on gastric emptying in ND-rats was reversed by all antagonists, and abolished in HFD-rats. In HFD-rats, carbachol-induced contractility was enhanced in gastric, but inhibited in ileal strips. HFD increased body weight, while serum triglycerides, alanine transaminase, aspartate aminotransferase, glucose, and levels of malondialdehyde, glutathione, myeloperoxidase activity, and luminolchemiluminescence in hepatic, ileal, and adipose tissues were similar in ND- and HFD-rats, but only lucigenin-chemiluminescence was Background/Aims Gastrointestinal motility changes contribute to development and maintenance of obesity. Nesfatin-1 (NES-1) is involved in central appetite control. The aim is to elucidate effects of NES-1 and high-fat diet (HFD) on gastrointestinal motility and to explore myenteric neuron expressions of tyrosine hydroxylase (TH), vasoactive intestinal peptide (VIP), and neuronal nitric oxide synthase (nNOS) in HFDinduced oxidative injury. Methods Sprague-Dawley rats were fed with normal diet (ND) or HFD. Gastric emptying rate was measured following NES-1 (5 pmol/rat, intracerebroventricular) preceded by subcutaneous injections of glucagon-like peptide 1 (GLP-1), cholecystokinin 1 (CCK-1), and gastrin/CCK-2 receptor antagonists. In carbachol-contracted gastric and ileal strips, contractile changes were recorded by adding NES1 (0.3 nmol/L), GLP-1, CCK-1, and gastrin/CCK-2 antagonists. Results Neither HFD nor NES-1 changed methylcellulose emptying, but NES-1 delayed saline emptying in cannulated ND-rats. Inhibitory effect of NES-1 on gastric emptying in ND-rats was reversed by all antagonists, and abolished in HFD-rats. In HFD-rats, carbachol-induced contractility was enhanced in gastric, but inhibited in ileal strips. HFD increased body weight, while serum triglycerides, alanine transaminase, aspartate aminotransferase, glucose, and levels of malondialdehyde, glutathione, myeloperoxidase activity, and luminolchemiluminescence in hepatic, ileal, and adipose tissues were similar in ND-and HFD-rats, but only lucigenin-chemiluminescence was increased in HFD-rats. Vasoactive intestinal peptide (VIP) and TH immunoreactivities were depressed and nNOS immunoreactivity was increased in gastric tissues of HFD-rats, while VIP and TH were enhanced, but nNOS was reduced in their intestines. Conclusions HFD caused mild systemic inflammation, disrupted enteric innervation, enhanced gastric contractility, inhibited ileal contractility, and eliminated inhibitory effect of NES-1 on gastric motility. (J Neurogastroenterol Motil 2021;27:265-278)Publication Metadata only Estrogen supplementation alleviates stress-induced gastric ulcer in post-menopausal rats: the dominant role of estrogen-beta receptors(2022-05-24) KAYA, ÖZLEM TUĞÇE; YEGEN, ŞEVKET CUMHUR; ERCAN, FERİHA; YEGEN, BERRAK; YÜKSEL, MERAL; Şen L. S., Altınoluk T., İpek B. E., Akbulut S., Kaya Ö. T., Ercan F., Yüksel M., Yegen Ş. C., Yegen B.Publication Open Access A 10-day mild treadmill exercise performed before an epileptic seizure alleviates oxidative injury in the skeletal muscle and brain tissues of the rats(2022-01-01) KAYA, ÖZLEM TUĞÇE; YEGEN, BERRAK; YÜKSEL, MERAL; YILDIRIM, ALPER; Arabaci -Tamer S., KAYA Ö. T., YÜKSEL M., YILDIRIM A., YEGEN B.© 2022 Marmara University Press, All Rights Reserved.Objective: Epileptic seizures may cause skeletal muscle injury and memory dysfunctions. The present study was aimed to investigate the possible protective effects of exercising prior to seizure on seizure-induced oxidative injury in the skeletal muscle and brain. Materials and Methods: Sprague-Dawley male rats were assigned as non-exercise (n=16) and exercise groups (n=16). Following a 3-day exercise training, exercise protocol (30 min) was performed on a treadmill for 10 days, while control rats had no exercise. On the 11th day, the epileptic seizure was induced by a single intraperitoneal injection of pentylenetetrazol (PTZ) (45 mg/kg), while the control groups were injected with saline. Passive-avoidance test was initially performed before PTZ/saline injection and repeated 72 h later for the assessment of memory function. Brain and gastrocnemius muscles were taken for histological assessments and to determine the levels of malondialdehyde (MDA) and glutathione (GSH), myeloperoxidase (MPO) activity and luminal – and lucigenin – enhanced chemiluminescence levels. Results: Exercise training alone increased the formation of reactive oxygen species and elevated the antioxidant GSH capacity of the muscle tissue in the control rats, but these effects were not observed in the muscles of the exercised rats induced with a PTZ-seizure. On the other hand, short-term exercise alone had no effect on the basal oxidative parameters of the brain tissues. Prior exercise did not alter the average seizure scores or memory performances when compared to non-exercised groups, but suppressed the PTZ-induced elevations in MDA and chemiluminescence levels as well as MPO activity in the brain. Conclusion: A 10-day mild treadmill exercise reduced the oxidative brain damage due to a single seizure-induced excitotoxicity and exerted a preconditioning effect on the skeletal muscles exposed to tonic-clonic contractions.