Person: YILDIRIM, ALPER
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YILDIRIM
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ALPER
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Publication Metadata only Phosphodiesterase-5 inhibition by sildenafil citrate in a rat model of bleomycin-induced lung fibrosis(ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 2010) YILDIRIM, ALPER; Yildirim, Alper; Ersoy, Yasemin; Ercan, Feriha; Atukeren, Pinar; Gumustas, Koray; Uslu, Unal; Alican, InciSildenafil, a selective and potent inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase (PDE)5, has a relaxant effect on the smooth muscle cells of the arterioles supplying the human corpus cavernosum acting via nitric oxide (NO)-dependent mechanism. This study aimed to investigate the possible protective effect of sildenafil citrate on the extent of tissue integrity, oxidant-antioxidant status and neutrophil infiltration to the inflamed organ in a rat model of bleomycin-induced lung fibrosis. Lung fibrosis was induced by intratracheal administration of 0.1 ml of bleomycin hydrochloride (5 mg/kg in 0.9% NaCl) under anesthesia to Sprague-Dawley rats (200-250 g; n =7-8 per group). Control rats received an equal volume of saline intratracheally. In the treatment groups, the rats were treated with either sildenafil citrate (10 mg/kg per day; subcutaneously) or saline for 14 days. Another group of rats were administered subcutaneously with N(G)-nitro-L-arginine methyl ester (L-NAME; 20 mg/kg in 0.9% NaCI) 5 min after sildenafil injections. After decapitation, the lungs were excised and taken for microscopic evaluation or stored for the measurement of malondialdehyde (MDA) and glutathione (GSH) levels, and myeloperoxidase (MPO) activity, and for the assessment of apoptosis. Trunk blood was collected for the assessment of serum tumor necrosis factor (TNF)-alpha and interleukin (1)-1 beta levels. In the group with lung fibrosis, the lung tissue was characterized by microscopic lesions, increased lipid peroxidation with a concomitant reduction in GSH content, increased MPO activity and apoptosis. Serum TNF-alpha and IL-1 beta levels were higher in the lung fibrosis group compared to control values. Sildenafil reversed tissue MDA levels, MPO activity and serum pro-inflammatory cytokine levels, and preserved GSH content although its effect on the extent of tissue lesion and apoptosis was not statistically significant. Treatment with L-NAME reversed the effect of sildenafil on GSH content. In conclusion, sildenafil citrate administration to rats with bleomycin-induced lung fibrosis seems to be beneficial via prevention of lipid peroxidation, cytokine production and/or release and neutrophil accumulation. (C) 2009 Elsevier Ltd. All rights reserved.Publication Metadata only Nesfatin-1 ameliorates testicular injury and supports gonadal function in rats induced with testis torsion(ELSEVIER SCIENCE INC, 2018) YILDIRIM, ALPER; Tamer, Sevil Arabaci; Yildirim, Alper; Koroglu, M. Kutay; Cevik, Ozge; Ercan, Feriha; Yegen, Berrak C.Testicular torsion causes ischemia-reperfusion injury and an increased risk of infertility. Nesfatin-1 is a novel peptide with antioxidant, anti-inflammatory and anti-apoptotic properties. In the present study, we aimed to investigate the putative beneficial effects of nesfatin-1 on oxidative injury and impaired testicular function induced by testis torsion. Under anesthesia, male Sprague-Dawley rats (180-230 g; n = 24) had sham-operation or they underwent testicular torsion by rotating the left testis 720 degrees and fixing it for 2 h, followed by a 2-h detorsion. Rats in each group were treated intraperitoneally with either nesfatin-1 (0.3 mu g/kg) or saline prior to the torsion or sham-torsion. At the end of the 4-h experimental period, tissue samples were removed for evaluation of spermatozoa, molecular and histochemical analyses. In saline-treated torsion/detorsion group, a high percentage of abnormal spermatozoa with head defects was observed, which was abolished in nesfatin-1 -treated torsion/detorsion group. The levels of 8-OHdG, tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, caspase-3 were increased in the saline-treated torsion/detorsion group as compared to sham-operated group, while nesfatin-1 pre-treatment significantly decreased the expressions of the pro-inflammatory cytokines, depressed apoptosis, and also reduced the tubular degeneration. In addition, nesfatin-1 in torsion/detorsion group elevated expressions of transforming growth factor (TGF)-beta and reduced expressions of protein kinase B (AKT) and cAMP response element binding protein (CREB) in the testis tissue. The present findings show that nesfatin-1, by regulating AKT and CREB signaling pathways and pro-inflammatory/anti-inflammatory cytokine balance, preserves the spermatogenic cells and ameliorates torsion-detorsion-induced tubular degeneration.Publication Open Access Impaired vasomotor function induced by the combination of hypertension and hypercholesterolemia(ELSEVIER SCIENCE INC, 2013-01) YILDIRIM, ALPER; Kurtel, Hizir; Rodrigues, Stephen F.; Yilmaz, Cigdem E.; Yildirim, Alper; Granger, D. NeilAlthough it is well known that endothelial function is compromised in the presence of either hypertension (HTN) or hypercholesterolemia (HCh), less is known about whether and how the combination of these risk factors (HTN+HCh) results in impaired endothelium-dependent dilation (EDD). The aims of this study were to evaluate the influence of HTN+HCh on vasomotor function and to identify the mechanisms that underlie the altered vascular reactivity elicited by HTN+HCh. Endothelium-dependent and -independent vasomotor responses of aortic vessels were studied in mice with diet-induced HCh and/or HTN induced by chronic administration of either angiotensin II (AngII) or deoxycorticosterone acetate-salt. HTN+HCh elicited an impairment of EDD that appeared between each risk factor alone. Incubation with catalase resulted in more severe EDD impairment. Each risk factor enhanced vascular H2O2 production, but a larger response was noted with HTN+HCh. An attenuated EDD was not observed in AngII type la receptor deficient (AT1r(-/-)) mice, but AT1r(-/-) bone marrow chimeras exhibited more profound impairment compared with wild-type. HTN+HCh does not exert an additive effect of vasomotor dysfunction compared with either risk factor alone, and both H2O2 and blood cell-associated AT1r contribute to the impaired EDD responses in mice with HTN+HCh. J Am Soc Hypertens 2013;7(1):14-23. (C) 2013 American Society of Hypertension. All rights reserved.Publication Metadata only Treatment with estrogen receptor agonist ER beta improves torsion-induced oxidative testis injury in rats(PERGAMON-ELSEVIER SCIENCE LTD, 2019) YILDIRIM, ALPER; Tamer, Sevil Arabaci; Yildirim, Alper; Arabaci, Sule; Ciftci, Selin; Akin, Sena; Sari, Elif; Koroglu, M. Kutay; Ercan, Feriha; Yuksel, Meral; Cevik, Ozge; Yegen, Berrak C.Aims: The purpose of the present study was to investigate the potential antioxidant, anti-apoptotic and sperm function-preserving effects of estrogen, estrogen receptor (ER) a and ER beta agonists in a rat model of testis torsion-detorsion (T/D). Main methods: Under anesthesia, 6-8-week-old male Sprague-Dawley rats underwent sham-operation or testicular torsion by fixing left testis rotated at 720 degrees for 2 h. After detorsion, rats were treated with ER alpha agonist (1 mg/kg/day, subcutaneously, sc) or ER beta agonist (1 mg/kg/day, sc) or estradiol (E-2, 1 mg/kg/day, in drinking water) or vehicle on the following two days. On the third day, testicular blood-flow was recorded and then left testes were extracted for molecular and histochemical analysis. Key findings: The findings showed that reduced testicular blood-flow following torsion was partially restored on the 3rd day of detorsion, while treatments with either of the ER agonists or E-2 returned blood flow fully back to the control levels. When the testis-torsioned rats were given ER beta agonist during the detorsion period, tubular injury was lessened, sperm count and motility were increased, while the production of reactive oxygen meta-bolites and apoptosis in the testis tissues were totally suppressed. Although a down-regulated expression of androgen receptor (AR) along with a reduction in serum testosterone level was observed in the vehicle-treated T/D group, all three treatments up-regulated the expressions of AR and its mRNA, while ER alpha agonist and E-2 suppressed the testosterone level. Significance: ER beta receptor activation during the post-ischemic period may be beneficial in protection against torsion-related oxidant testicular injury and infertility.