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Öğe Effects of Melatonin on Cardiac Ion Channels in Rats with Metabolic Syndrome(Wiley, 2022) Ovali, Mehmet Akif; Oztopuz, Ozlem; Vardar, Selma Arzu[Abstract Not Available]Öğe Melatonin ameliorates cardiac remodelling in fructose-induced metabolic syndrome rat model by using genes encoding cardiac potassium ion channels(Springer, 2021) Ovali, Mehmet Akif; Oztopuz, Ozlem; Vardar, Selma ArzuBackground Metabolic syndrome comprises a group of disorders, including cardiac abnormalities. Ventricular arrhythmias observed in metabolic syndrome are due to the impaired ventricular repolarization. This study aims to determine the effects of melatonin on cardiac ventricular repolarization in metabolic syndrome rat model. Methods and results Sprague-Dawley rats were divided into control (n = 8), melatonin (n = 8), metabolic syndrome (n = 8) and metabolic syndrome + melatonin (n = 8) groups. Fructose (200 g/lt/day) was added into the drinking water during 8 weeks of rats to induce metabolic syndrome model. In the last two weeks, melatonin (20 mg/kg/day) was administered via oral gavage. Blood pressure measurements and ECG recordings were taken at three different times. Blood and left ventricular tissue samples were harvested and the KCNQ1,3 and KCNH2 gene expressions were analysed by qRT-PCR method. We observed insulin resistance, hyperglycemia, dyslipidemia and higher systolic blood pressure in metabolic syndrome group (p < 0.01, for all). Prolonged QT interval was observed in metabolic syndrome group (p < 0.001). The expression levels of the KCNQ genes encoding the Kv7 channel was significantly reduced, however KCNH2 gene which encodes Kv11.1 channel was increased in metabolic syndrome group compared to control group (p < 0.05, p < 0.001, respectively). Melatonin significantly normalised the prolongation on QT interval in metabolic syndrome group (p < 0.001) and the expressions of the KCNQ (p < 0.002) and KCNH2 genes (p = 0.003). Conclusions The present study revealed that melatonin had ameliorative effects on ventricular repolarization by improving the prolonged QT duration in rats with metabolic syndrome and this effect was generated by the KCNQ and KCNH2 gene families.Öğe Melatonin Improves Left Ventricular Mitochondrial Dynamics in Rats(Pleiades Publishing Inc, 2022) Uzun, Metehan; Oztopuz, Ozlem; Eroglu, Huseyin Avni; Doganlar, Oguzhan; Doganlar, Zeynep Banu; Ovali, Mehmet Akif; Demir, UfukThere is increasing awareness that efficient and regular mitochondrial dynamics improvement cardiac function and affects the quality of life. Melatonin is a main pineal gland hormones and ameliorates mitochondrial dynamics in many cardiac disorders. For that purpose, we administrated melatonin to healthy rats all day long in order to investigate change in left ventricle mitochondrial dynamics both in the end of the nighttime and daytime. Twenty male Wistar rats (3-4 months age) were randomly assigned into Control (C; n = 10) and Melatonin groups (MEL; 10 mg/kg melatonin added drinking water, n = 10). On the 5th day of the study, 5 rats from the groups were randomly selected and euthanized at 08:00 AM and the remaining 5 rats were euthanized at 20:00 PM from each groups and samples of left ventricle (LV) tissue were harvested. Quantitative real-time PCR and western blot analysis demonstrated that melatonin acts preventive role on mitochondrial fusion and mitophagy through the DRP1/FIS1 and BNIP3/NIX axis, respectively. Additionally, melatonin administration significantly reduced P21 activation, induced cell cycle arrest, P27, finally regulated caspase-depended mitochondrial apoptosis signals in a time dependent manner. Our results suggest that melatonin may emerge as a therapeutic candidate to protect the bioenergetic dynamics of mitochondria in hearth.Öğe The Role of Melatonin in Oxidative Stress, DNA Damage, Apoptosis and Angiogenesis in Fetal Eye under Preeclampsia and Melatonin Deficiency Stress(Taylor & Francis Inc, 2019) Doganlar, Zeynep Banu; Guclu, Hande; Oztopuz, Ozlem; Turkon, Hakan; Dogan, Ayten; Uzun, Metehan; Doganlar, OguzhanAim: The aim of this study was to investigate the possible mechanisms of ocular damage induced by pinealectomy (PNX) and preeclampsia (PE), and to determine the cellular and molecular effects of melatonin treatment on oxidative stress, DNA damage, molecular chaperone responses, induction of apoptosis and angiogenesis in the fetal eye of both PNX and PNX+PE animals. Material and Methods: We analysed therapeutic potential of melatonin on fetal eye damage in PNX and PNX+PE animals using Malondialdehyde (MDA), Random Amplified Polymorphic DNA (RAPD), qRT-PCR and Western blot assays. Results: Our study presents three preliminary findings: (a) in fetal eye tissues, PNX and PNX+PE significantly induce oxidative damage to both DNA and protein contents, leading to a dramatic increase in caspase-dependent apoptotic signalling in both mitochondrial and death receptor pathways; (b) the same conditions trigger hypoxia biomarkers in addition to significant overexpression of HIF1-alpha, HIF1-beta, MMP9 and VEGF genes in the fetal eye; (c) finally, melatonin regulates not only the expression of genes encoding antioxidant enzymes and increase in DNA damage as well as lipid peroxidation but also limits programmed cell death processes in the fetal eye of PNX and PNX+PE animals . Furthermore, melatonin can relatively modulate genes in the HIF1 family, TNF-alpha and VEGF, thus acting as a direct anti-angiogenic molecule. In conclusion, both PNX and PNX+PE induce ocular damage at both cellular and molecular levels in fetal eye tissue of rats. Conclusion: Our results clearly indicate the potential of melatonin as a preventative therapeutic intervention for fetal ocular damage triggered by both PNX and PNX+PE.
