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Öğe Antihyperalgesic and antiallodynic effect of sirolimus in neuropathic pain and the role of cytokines in this effect(Elsevier Ireland Ltd, 2010) Orhan, Cahide Elf; Onal, Aytuel; Ulker, SibelRecent studies have revealed that T lymphocytes play a role in neuropathic pain following nerve injury in rats through releasing several cytokines. Sirolimus is an immunosuppressive antibiotic inhibiting T cell activation. This study aimed to determine the effect of sirolimus on hyperalgesia and allodynia and on serum and spinal cord TNF-alpha, IL-1 beta and IL-6 levels in rat neuropathic pain Neuropathic pain was induced by loose ligation of the sciatic nerve and evaluated by tests measuring the mechanical hyperalgesia and allodynia. Sirolimus (0.75 and 1 5 mg/kg) was administered intraperitoneally once every 3 days for 2 weeks (7 doses totally). This dosing regimen revealed acceptable blood concentrations in neuropathic rats Chronic constriction injury of the sciatic nerve resulted in hyperalgesia and allodynia. Serum levels of cytokines remained unchanged in neuropathic rats However, TNF-alpha, but not IL-1 beta or IL-6, protein level was increased in the spinal cord tissue as evaluated by Western blotting analysis Treatment with sirolimus resulted in antihyperalgesic and antiallodynic effects and prevented the increased spinal cord TNF-alpha level. It seems that sirolimus could be a promising immunosuppressive agent in the treatment of neuropathic pain. (C) 2010 Elsevier Ireland Ltd All rights reservedÖğe Antihyperalgesic and antiallodynic effect of sirolimus in rat model of adjuvant arthritis(Elsevier Science Bv, 2013) Orhan, Cahide Elif; Onal, Aytul; Uyanikgil, Yigit; Ulker, SibelSirolimus is an immunosupressive drug that specifically inhibit the activation of T-lymphocytes. This study was undertaken to investigate whether treatment with sirolimus exert analgesic effect in rat adjuvant-induced arthritis, an animal model of rheumatoid arthritis. Arthritis was induced by a single subcutaneous injection of Freund's complete adjuvant to male Wistar rats that were divided into four groups; control (saline), vehicle (ethanol), sirolimus 0.75 and sirolimus 1.5. Sirolimus (0.75 and 1.5 mg/kg/day) was administered intraperitoneally using Monday-Wednesday-Friday dosing schedule for 29 days, this dosing regimen revealed acceptable trough blood concentrations in arthritic rats. Adjuvant inoculation resulted in paw inflammation, hyperalgesia and allodynia as assessed by pletismometer, analgesymeter and dynamic plantar aesthesiometer respectively. Light microscopic evaluation of the arthritic metacarpophalangeal joints revealed synovial hypertrophy with inflammatory cellular infiltration, cartilage destruction and partial subchondral bone resorption. ELISA tests of serum TNF-alpha, IL-1 beta or IL-6 did not show any change in arthritic rats, while Western blotting analysis revealed a significant increase in TNF-alpha (P<0.001), but not IL-1 beta or IL-6, protein expression in the lumbar spinal cord of arthritic rats. Treatment with sirolimus significantly decreased the arthritic lesions (P<0.001) and paw swelling (P<0.05), alleviated the histological features in the metacarpophalangeal joint, resulted in antihyperalgesic and antiallodynic effects without affecting the locomotor activity and prevented the increased spinal cord TNF-alpha level (P<0.05). It seems that prevention of the increased TNF-alpha expression in the spinal cord may partially contribute to the antihyperalgesic effect of sirolimus in adjuvant arthritic rats and sirolimus could be a promising immunosupressive agent in the treatment of arthritic pain. (C) 2013 Elsevier B.V. All rights reserved.Öğe Apocynin restores endothelial dysfunction in streptozotocin diabetic rats through regulation of nitric oxide synthase and NADPH oxidase expressions(Elsevier Science Inc, 2010) Olukman, Murat; Orhan, Cahide Elif; Celenk, Fatma Gul; Ulker, SibelAim: Increased production of reactive oxygen species (ROS) in the diabetic vasculature results in the impairment of nitric oxide (NO)mediated relaxations leading to impaired endothelium-dependent vasodilation. An important source of ROS is nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and the inhibition of this enzyme is an active area of interest. This study aimed to investigate the effects of apocynin, an NADPH oxidase inhibitor, on endothelial dysfunction and on the expression of NO synthase (NOS) and NADPH oxidase in thoracic aorta of diabetic rats. Method: Streptozotocin (STZ)-diabetic rats received apocynin (16 mg/kg per day) for 4 weeks. Endothelium-dependent and -independent relaxations were determined in thoracic aortic rings. Western blotting and RT-PCR analysis were performed for NOSs and NADPH oxidase in the aortic tissue. Results: Acetylcholine-induced relaxations and L-NAME-induced contractions were decreased in diabetic aorta. The decrease in acetylcholine and L-NAME responses were prevented by apocynin treatment without a significant change in plasma glucose levels. Endothelial NOS (eNOS) protein and mRNA expression exhibited significant decrease in diabetes, while protein and/or mRNA expressions of inducible NOS (iNOS) as well as p22(phox) and gp91(phox) subunits of NADPH oxidase were increased, and these alterations were markedly prevented by apocynin treatment. Conclusion: NADPH oxidase expression is increased in diabetic rat aorta. NADPH oxidase-mediated oxidative stress is accompanied by the decreased eNOS and increased iNOS expressions, contributing to endothelial dysfunction. Apocynin effectively prevents the increased NADPH oxidase expression in diabetic aorta and restores the alterations in NOS expression, blocking the vicious cycle leading to diabetes-associated endothelial dysfunction. (C) 2010 Elsevier Inc. All rights reserved.Öğe Effect of vitamin E and C supplementation combined with oral antidiabetic therapy on the endothelial dysfunction in the neonatally streptozotocin injected diabetic rat(Wiley, 2006) Alper, Gulinnaz; Olukman, Murat; Irer, Seda; Caglayan, Osman; Duman, Erdal; Yilmaz, Candeger; Ulker, SibelBackground This study investigates the contribution of vitamin supplementation to the efficacy of oral antidiabetic therapy on the reversal of endothelial dysfunction in a model of type-2 diabetes in rat. Methods Diabetes was induced by streptozotocin injection to neonatal rats which were breastfed for 4 weeks, then fed 6 weeks with normal food or food supplemented with 2% vitamin E and 4% vitamin C. Some diabetic rats were treated with gliclazide for 6 weeks. Endothelium-dependent and -independent relaxations to acetylcholine and sodium nitroprusside (SNP) were recorded in thoracic aortic rings. Plasma insulin, HbA(1c) and antioxidant vitamins (A, C and E); plasma and aortic malondialdehyde (NIDA) levels were determined. Results Induction of diabetes resulted in decreased body weight and increased blood glucose, plasma insulin and HbA(1c) levels compared to controls. Acetylcholine relaxation was impaired in diabetic aorta, while SNP relaxation remained unchanged. Aortic MDA level was significantly higher, while plasma vitamin levels were lower in diabetic rats. Diminished acetylcholine response, enhanced aortic MDA level and decreased plasma vitamin levels were all restored after gliclazide and/or vitamin therapy. However, vitamin supplementation in control rats significantly impaired acetylcholine relaxations and increased aortic MDA levels. Conclusions Apparently, a selective endothelial dysfunction accompanies the imbalance in oxidant/antioxidant status in the type-2 diabetes model of rat and gliclazide and/or vitamin supplementation improves the impairment in diabetic vasculature. However, vitamin supplementation triggers oxidative stress in normal aortic tissue, thereby, leads to endothelial dysfunction; indicating that nutritional extra-supplementation of antioxidant vitamins isn't advisable for normal subjects, although it's beneficial in disease status. Copyright (c) 2005 John Wiley & Sons, Ltd.Öğe Effects of cyanocobalamin and its combination with morphine on neuropathic rats and the relationship between these effects and thrombospondin-4 expression(Korean Pain Soc, 2022) Duzenli, Neslihan; Ulker, Sibel; Sengul, Gulgun; Kayhan, Buse; Onal, AytulBackground: Thrombospondin-4 (TSP4) upregulates in the spinal cord following peripheral nerve injury and contributes to the development of neuropathic pain (NP). We investigated the effects of cyanocobalamin alone or in combination with morphine on pain and the relationship between these effects and spinal TSP4 expression in neuropathic rats. Methods: NP was induced by chronic constriction injury (CCI) of the sciatic nerve. Cyanocobalamin (5 and 10 mg/kg/day) was administered 15 days before CCI and then for 4 and 14 postoperative days. Morphine (2.5 and 5 mg/kg/day) was administered only post-CCI. Combination treatment included cyanocobalamin and morphine, 10 and 5 mg/kg/day, respectively. All drugs were administered intraperitoneally. Nociceptive thresholds were detected by esthesiometer, analgesia meter, and plantar test, and TSP4 expression was assessed by western blotting and fluorescence immunohistochemistry. Results: CCI decreased nociceptive thresholds in all tests and induced TSP4 expression on the 4th postoperative day. The decrease in nociceptive thresholds persisted except for the plantar test, and the increased TSP4 expression reversed on the 14th postoperative day. Cyanocobalamin and low-dose morphine alone did not produce any antinociceptive effects. High-dose morphine improved the decreased nociceptive thresholds in the esthesiometer when administered alone but combined with cyanocobalamin in all tests. Cyanocobalamin and morphine significantly induced TSP4 expression when administered alone in both doses for 4 or 14 days. However, this increase was less when the two drugs are combined. Conclusions: The combination of cyanocobalamin and morphine is more effective in antinociception and partially decreased the induced TSP4 expression compared to the use of either drug alone.Öğe Esophageal Epithelial Resistance and Lower Esophageal Sphincter Muscle Contraction Increase in a Chronic Diabetic Rabbit Model(Springer, 2016) Capanoglu, Doga; Coskunsever, Deniz; Olukman, Murat; Ulker, Sibel; Bor, SerhatEsophageal motility disorders and possibly gastroesophageal reflux disease are common in patients with diabetes mellitus. We aimed to investigate both the electrophysiological characteristics of the esophageal epithelium and the contractility of the lower esophageal sphincter (LES) muscle in alloxane-induced diabetic rabbits. Electrophysiological properties were measured using an Ussing chamber method. An acid-pepsin model was employed with pH 1.7 or weakly acidic (pH 4) Ringer and/or pepsin. Smooth muscle strips of the LES were mounted in an isolated organ bath. Contractile responses to an electrical field stimulation and cumulative concentrations of acetylcholine were recorded. Contractility of the muscle strips were tested in the presence of Rho-kinase inhibitor (Y-27632) and nonspecific nitric oxide inhibitor (L-NAME). The resistance of diabetic tissue perfused in the pH 1.7 Ringer decreased 17 %; pepsin addition decreased it by 49 %. The same concentrations caused a more distinct loss of resistance in the control tissues (22 and 76 %, p < 0.05). The perfusion of tissues in increased concentrations of luminal and serosal glucose did not change the tissue resistance and voltage. Diabetes significantly increased both the electrical field stimulation and acetylcholine-induced contractions in the LES muscle strips (p < 0.01). Incubation with Y-27632 significantly decreased the acetylcholine-induced contractions in a concentration-dependent manner (p < 0.01). The acid-pepsin model in the diabetic rabbit esophageal tissue had less injury compared with the control. The diabetic rabbit LES muscle had higher contractility, possibly because of the activation of the Rho-Rhokinase pathway. Our results show that in a chronic diabetic rabbit model the esophagus resists reflux by activating mechanisms of mucosal defense and increasing the contractility of the LES.Öğe A First-in-Human Phase I Study to Evaluate the Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of a Novel Anti-Interleukin 1 Biologic Agent, Rph-104, in Healthy Subjects(Wiley, 2017) Gul, Ahmet; Ulker, Sibel; Senturk, Recep Selim; Turk, Ugur Onsel; Gurgun, Cemil; Lavrovsky, Yan; Samsonov, Mikhail; Ozen, Sebnem; Altinel, SerdarÖğe Light, electron microscopic and immunohistochemical study of the effect of low-dose aspirin during the proestrus phase on rat endometrium in the preimplantation period(Sci Printers & Publ Inc, 2007) Ates, Utku; Baka, Meral; Turgut, Mehmet; Uyanikgil, Yigit; Ulker, Sibel; Yilmaz, Ozlem; Tavmergen, Erol; Yurtseven, MineOBJECTIVE: To evaluate structural alterations in rat endometrium at preimplantation following treatment with aspirin beginning from proestrus by light microscopy, electron microscopy and immunohistochemical techniques. STUDY DESIGN: Twenty rats were divided into control (n =10) and experimental (n =10) groups. Experimental rats were treated with low-dose aspirin daily (2 mg/kg/day) during estrus, beginning from the proestrus phase, mated at end of cycle and treated with aspirin. Untreated pregnant rats were the control group. Rats in both groups were sacrificed at the 84th pregnancy hour; the uterus was rapidly removed and dissected free of surrounding adipose tissue. Uteri specimensfrom nonpregnant rats were transferred into fixative solution and processed for light, electron microscopic and immunohistochemical study. RESULTS: Light and electron microscopy of endometrium from control rats conformed to mid-diestrus phase; endometrial histology of the aspirin-treated group conformed to late diestrus phase. The endometrial layer was significantly thicker in the aspirin-treated group compared to the untreated control group (p < 0.001). No significant difference was found in vessel number between groups. Staining with alpha V integrin was more dense in the aspirin-treated group. CONCLUSION: Based on histologic findings, we suggest low-dose aspirin has positive effects on preparing endometrium before implantation.Öğe Milnacipran attenuates hyperalgesia and potentiates antihyperalgesic effect of tramadol in rats with mononeuropathic pain(Pergamon-Elsevier Science Ltd, 2007) Onal, Aytul; Parlar, Ayse; Ulker, SibelMilnacipran is a non-tricyclic antidepressant drug which selectively inhibits serotonin and noradrenaline re-uptake and is recommended in the treatment of various chronic pain syndromes. Many studies have shown that compounds known to block monoamine uptake potentiate the antinociceptive effects of opioids. This study investigates the effect of milnacipran alone or in combination with an opiodergic drug, i.e. tramadol, on hyperalgesia in a rat model of neuropathic pain. The contribution of serotonergic, noradrenergic and opioidergic systems in the potential antihyperalgesic effect of milnacipran has also been examined. Chronic constriction injury was induced in rats by loose ligation of the sciatic nerve and neuropathic pain was evaluated 14 days after surgery. Intraperitoneal acute injection of milnacipran 60 mg/kg produced an antihyperalgesic effect which was prevented by pretreating systemically with alpha-methyl-p-tyrosine, an inhibitor of noradrenaline synthesis; parachlorophenylalanine, an inhibitor of serotonin synthesis; and naloxone, an antagonist of opioidergic receptors. Co-administration of milnacipran 40 mg/kg with tramadol (20 and 40 mg/kg) potentiated the antihyperalgesic effect of tramadol. Milnacipran has an antihyperalgesic effect mediated by serotonergic, noradrenergic and opioidergic systems and the combined use of tramadol with milnacipran potentiates the effect of tramadol in the management of neuropathic pain. (C) 2007 Elsevier Inc. All rights reserved.Öğe Nitric oxide does not downregulate Rho-kinase (ROCK-2) expression in rat coronary endothelial cells(Lippincott Williams & Wilkins, 2008) Tiftik, R. Nalan; Erol, Ayse; Cinar, Mehtap G.; Kubat, Havva; Ark, Mustafa; Ulker, Sibel; Buyukafsar, KansuRho kinase (ROCK) and nitric oxide (NO) are important targets in cardiovascular diseases. Therefore, we investigated the possible influence of NO on Rho kinase (ROCK-2 isoform) expressions in cultured rat coronary microvascular endothelial cells. The cells were isolated from Wistar rats on a Langendorff system, and were incubated overnight (similar to 16 h) with an NO generator, A-23187 (10(-7) to 10(-6) M) NO donors, such as sodium nitroprusside (10(-7) to 10-6 M) glyceryl trinitrate (10(-7) to 10-6 M), 2,2'-(hydroxynitro- sohydrazono)bis-ethanimine (10(-7) to 10(-6) M), and NaNO2 (10(-4) to 10(-3) M) or a nitric oxide synthase (NOS) inhibitor, N-G-nitro-L-arginme methylester (2x10(-4) M), or two ROCK inhibitors, (-+)(R)-trans-4-(1-aminoethyl)- N-(4-pyridyl) cyclohexanecarboxamide dihydrochloride monohydrate (Y-27632, 10(-5) M) and fasudil (10(-5) M) in the absence or presence of thrombin (4 U/mL). ROCK-2 and endothelial NOS (eNOS) expressions were detected by Western blotting. Moreover, nitrite/nitrate levels were detected by Griess method in the presence of the ROCK inhibitors. The NO donors and the NO generator had no significant effects on ROCK-2 expression. Y-27632 and fasudil did not alter eNOS expression and NO production. Nitrite/nitrate levels were 4.4 +/- 0.32 mu M in control and 4.0 +/- 0.93 mu M and in Y-27632 group. These results demonstrate that prolong NO donation could not suppress the expression of ROCK-2 protein, and the ROCK inhibitor did not change e-NOS expression and NO production in the cultured rat coronary microvascular endothelial cells.Öğe Treatment with NADPH oxidase inhibitor apocynin alleviates diabetic neuropathic pain in rats(Wolters Kluwer Medknow Publications, 2018) Olukman, Murat; Onal, Aytul; Celenk, Fatma Gul; Uyanikgil, Yigit; Cavusoglu, Turker; Duzenli, Neslihan; Ulker, SibelIncreased reactive oxygen species by the activation of NADPH oxidase (NOX) contributes to the development of diabetic complications. Apocynin, a NOX inhibitor, increases sciatic nerve conductance and blood flow in diabetic rats. We investigated potential protective effect of apocynin in rat diabetic neuropathy and its precise mechanism of action at molecular level. Rat models of streptozotocin-induced diabetes were treated with apocynin (30 and 100 mg/kg per day, intragastrically) for 4 weeks. Mechanical hyperalgesia and allodynia were determined weekly using analgesimeter and dynamic plantar aesthesiometer. Western blot analysis and histochemistry/immunohistochemistry were performed in the lumbar spinal cord and sciatic nerve respectively. Streptozotocin injection reduced pain threshold in analgesimeter, but not in aesthesiometer. Apocynin treatment increased pain threshold dose-dependently. Western blot analysis showed an increase in catalase and NOX-p47phox protein expression in the spinal cord. However, protein expressions of neuronal and inducible nitric oxide synthase (nNOS, iNOS), superoxide dismutase, glutathion peroxidase, nitrotyrosine, tumor necrosis factor-alpha, interleukin-6, interleukin-1 beta, aldose reductase, cyclooxygenase-2 or MAC-1 (marker for increased microgliosis) in the spinal cord remained unchanged. Western blot analysis results also demonstrated that apocynin decreased NOX-p47phox expression at both doses and catalase expression at 100 mg/kg per day. Histochemistry of diabetic sciatic nerve revealed marked degeneration. nNOS and iNOS immunoreactivities were increased, while S-100 immunoreactivity (Schwann cell marker) was decreased in sciatic nerve. Apocynin treatment reversed these changes dose-dependently. In conclusion, decreased pain threshold of diabetic rats was accompanied by increased NOX and catalase expression in the spinal cord and increased degeneration in the sciatic nerve characterized by increased NOS expression and Schwann cell loss. Apocynin treatment attenuates neuropathic pain by decelerating the increased oxidative stress-mediated pathogenesis in diabetic rats.Öğe Urotensin receptor antagonist palosuran attenuates cyclosporine-a-induced nephrotoxicity in rats(Wroclaw Medical Univ, 2019) Olukman, Murat; Can, Cenk; Coskunsever, Deniz; Uyanikgil, Yigit; Cavusoglu, Turker; Sozmen, Eser; Ulker, SibelBackground. Cyclosporine-A (CsA) is widely used for immunosuppressivetherapy in renal transplantation. Nephrotoxicity is the main dose-limiting undesirable consequence of CsA. Urotensin II (U-II), a novel peptide with a powerful influence on vascular biology, has been added to the list of potential renal vascular regulators. Upregulation of the urotensin receptors and elevation of plasma U-II levels are thought to possibly play a role in the etiology of renal failure. Objectives. the present study examines this hypothesis by evaluating renal function and histology with regard to the potential role of U-II and its antagonist, palosuran, in the pathogenesis of CsA-induced nephrotoxicity in rats. Material and methods. Male Sprague-Dawley rats were treated with CsA (15 mg/kg, for 21 days, intraperitoneally) or CsA + palosuran (300 mg/kg, for 21 days). Renal function was measured and histopathology, U-II immunostaining and protein detection with western blotting of the kidneys were performed. Results. Cyclosporine-A administration caused a marked decline in creatinine clearance (Ccr). Fractional sodium excretion (FENa) tended to increase in the CsA-treated rats. Plasma U-II levels decreased in the CsA-treated rats. Cyclosporine-A treatment resulted in a marked deterioration in renal histology and an increase in the expression of U-II protein in the kidneys. Palosuran's improvement of renal function manifested as a significant decrease in serum creatinine levels and a significant increase in urine creatinine levels, resulting in a marked increase in Ccr. Palosuran produced a significant normalization of kidney histology and prevented an increase in U-II expression. Conclusions. Cyclosporine-A-induced renal impairment was accompanied by an increase in U-II expression in kidneys and a contrary decrease in systemic U-II levels. Palosuran improved the condition of rats suffering from renal dysfunction by preventing the decrease in renal U-II expression without affecting the systemic levels of U-II. the protective effect of palosuran in CsA nephrotoxicity is possibly independent of its U-II receptor antagonism.
