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    Melatonin treatment against remote organ injury induced by renal ischemia reperfusion injury in diabetes mellitus
    (Pharmaceutical Soc Korea, 2008) Fadillioglu, Ersin; Kurcer, Zehra; Parlakpinar, Hakan; Iraz, Mustafa; Gursul, Cebrail
    Oxidative stress may have a role in liver damage after acute renal injury due to various reasons such as ischemia reperfusion (IR). Diabetes mellitus (DM) is an important disease for kidneys and may cause nephropathy as a long term complication. The aim of this study was to investigate protective effect of melatonin, a potent antioxidant, against distant organ injury on liver induced by renal IR in rats with or without DM. The rats were divided into six groups: control (n=7), DM (n=5), IR (n=7), DM+IR (n=7), melatonin+IR (Mel+IR) (melatonin, 4 mg/kg during 15 days) (n=7), and Mel+DM+IR groups (n=7). Diabetes developed 3 days after single i.p. dose of 45 mg/kg streptozotocin. After 15 day, the left renal artery was occluded for 30 min followed 24 h of reperfusion in IR performed groups. DM did not alter oxidative parameters alone in liver tissue. The levels of malondialdehyde, protein carbonyl and nitric oxide with activities of xanthine oxidase and myeloperoxidase were increased in liver tissues of diabetic and non-diabetic IR groups. Nitric oxide level in DM was higher than control. The activities of catalase and superoxide dismutase were increased in IR groups in comparison with control and DM. ALT and AST levels were higher in IR and DM+IR groups than control and DM. Melatonin treatment reversed all these oxidant and antioxidant parameters to control values as well as serum liver enzymes. We concluded that renal IR may affect distant organs such as liver and oxidative stress may play role on this injury, but DM has not an effect on kidney induced distant organ injury via oxidant stress. Also, it was concluded that melatonin treatment may prevent liver oxidant stress induced by distant injury of kidney IR.
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    Morphological Changes and Vascular Reactivity of Rat Thoracic Aorta Twelve Months After Pinealectomy
    (Ortadogu Ad Pres & Publ Co, 2010) Kurcer, Zehra; Ozturk, Feral; Sahna, Engin; Kurus, Meltem; Olmez, Ercument
    Objective: Melatonin, a hormone produced by the pineal gland, has been suggested to protect against development of hypertension and atherosclerosis. In this study, the effects of long-term melatonin deficiency for twelve months after pinealectomy on the alpha-adrenergic-contractions induced by phenylephrine, endothelium-dependent relaxation responses to acetylcholine and the morphological changes in the rat thoracic aorta were studied. Material and Metods: Rats were pinealectomized twelve months before the beginning of the vasomotor studies. Rings of arteries were mounted in isolated tissue baths for the measurements of isometric contractile force. The contractile responses to phenylephrine and endothelium-dependent relaxation responses to acetylcholine in the vessels were evaluated. Endothelial function was evaluated by vascular relaxation to acetylcholine. Histological examinations demonstrated the alterations of tunica media in the vessels of pinealectomized rats. Results: Thick and thin areas were observed in the transverse sections of vessels and the ratio of the widest media thickness to the narrowest was found significantly increased in pinealectomized group (2.85 +/- 056) when compared to the control group (1.65 +/- 0.10). In addition, alpha-smooth muscle actin and elastic lamellae staining of the media were attenuated in pinealectomized rats. Although contractile responses of vessels to phenylephrine in pinealectomized rats were lower than control group, significant difference was found for only one concentration (3x 10-8 mol l-1) of phenylephrine. There was no difference between the relaxation responses to acetylcholine in pinealectomized and control groups. Conclusion: These results show that long-term melatonin deficiency may cause some morphological changes in the tunics media of vessels. However, the function of endothelium and vascular responsiveness to proportional to-adrenergic stimulus seem to be mostly protected.