Person: AKAKIN, DİLEK
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AKAKIN
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DİLEK
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Publication Metadata only Protective effect of low dose caffeine on psychological stress and cognitive function(PERGAMON-ELSEVIER SCIENCE LTD, 2017) AKAKIN, DİLEK; Cakir, Ozgur Kasimay; Ellek, Nurfitnat; Salehin, Nabila; Hamamci, Rabia; Keles, Hulya; Kayali, Damla Gokceoglu; Akakin, Dilek; Yuksel, Meral; Ozbeyli, DilekIntroduction: Caffeine is an adrenergic antagonist that enhances neuronal activity. Psychological stress depresses cognitive function. Aim: To investigate the effects of acute and chronic low dose caffeine on anxiety-like behavior and cognitive functions of acute or chronic psychological stressed rats. Material-method: Acute or chronic caffeine (3 mg/kg) was administered to male Sprague Dawley rats (200-250 g, n = 42) before acute (cat odor) and chronic variable psychological stress (restraint overcrowding stress, elevated plus maze, cat odor, forced swimming) induction. Anxiety and cognitive functions were evaluated byhole-board and object recognition tests. The brain glutathione and malondialdehyde assays, myeloperoxidase, nitric oxide (NO), superoxide dismutase (SOD), luminol and lucigenin activity and histological examination were done. ANOVA and Student's t-test were used for statistical analysis. Results: The depressed cognitive function with chronic stress exposure and the increased anxiety-like behavior with both stress inductions were improved via both caffeine applications (p < 0.05-0.001). Both caffeine pretreatments in chronic stressed rats, and chronic caffeine in acute stressed ones reduced the elevated myeloperoxidase activities (p < 0.05-0.01). The increased malondialdehyde, lucigenin and NO levels with acute stress were inhibited with chronic caffeine (p < 0.05-0.01), malondialdehyde and NO levels were declined by acute caffeine (p < 0.001). Acute caffeine decreased SOD activity (p < 0.01) and improved glutathione (p < 0.01) and luminol levels (p < 0.05). The induced histological damage with both stress exposures was ameliorated with chronic caffeine. Conclusion: The increased anxiety-like behavior and depleted cognitive functions under stress conditions were improved with both acute and predominantly chronic caffeine pretreatments by decreasing oxidative damage parameters. (C) 2016 Elsevier Inc. All rights reserved.Publication Metadata only Functional and structural changes of the urinary bladder following spinal cord injury; treatment with alpha lipoic acid(WILEY, 2017) VELİOĞLU ÖĞÜNÇ, AYLİZ; Ekiz, Arif; Ozdemir-Kumral, Zarife Nigar; Ersahin, Mehmet; Tugtepe, Halil; Ogunc, Ayliz Velioglu; Akakin, Dilek; Kiran, Demir; Ozsavci, Derya; Biber, Necat; Hakan, Tayfun; Yegen, Berrak C.; Sener, Goksel; Toklu, Hale Z.BACKGROUND & AIMAlpha lipoic acid (LA) was shown to exert neuroprotection in trauma-induced spinal cord injury (SCI), which is frequently associated with urinary bladder complaints in patients with SCI. Accordingly, the protective effects of LA on biochemical and histological changes in bladder as well as functional studies were assessed. METHODSWistar albino rats were divided as control, SCI, and LA (50mg/kg/day, ip) treated SCI groups (SCI+LA). The standard weight-drop (100g/cm force at T10) method was used to induce a moderately severe SCI. One week after the injury, neurological examination was performed and the rats were decapitated. Bladder samples were taken for histological examination, functional (isolated tissue bath) studies, and for the measurement of biochemical parameters (malondialdehyde, MDA; gluthathione, GSH; nerve growth factor, NGF; caspase-3, luminol and lucigenin chemiluminescences). RESULTSSCI caused a significant (P<0.001) increase in the detrusor muscle thickness. It increased the contractility responses to carbachol and relaxation responses to papaverine (P<0.05-0.001). There were also significant alterations in MDA, caspase-3, luminol, and lucigenin chemiluminescences with concomitant decreases in NGF and GSH (P<0.05). LA treatment reversed histological and functional (contraction and relaxation responses) changes induced by SCI (P<0.05-0.001), but no significant recovery was observed in the impaired neurological functions. CONCLUSIONThese results indicate that LA have a beneficial effect in improving the bladder tonus via its antioxidant and anti-inflammatory actions following SCI.Publication Metadata only Melatonin improves hyperglycemia induced damages in rat brain(WILEY, 2018) YARAT, AYŞEN; Gurel-Gokmen, Begum; Ipekci, Hazal; Oktay, Sehkar; Alev, Burcin; Ustundag, Unsal Veli; Ak, Esin; Akakin, Dilek; Sener, Goksel; Emekli-Alturfan, Ebru; Yarat, Aysen; Tunali-Akbay, TugbaBackground Diabetes mellitus is an endocrine disorder which is characterized by the development of resistance to the cellular activity of insulin or inadequate insulin production. It leads to hyperglycemia, prolonged inflammation, and oxidative stress. Oxidative stress is assumed to play an important role in the development of diabetic complications. Melatonin is the hormone that interacts with insulin in diabetes. Therefore, in this study, the effects of melatonin treatment with or without insulin were examined in diabetic rat brain. Methods Results Rats were divided into five groups as control, diabetes, diabetes + insulin, diabetes + melatonin, and diabetes + melatonin + insulin. Experimental diabetes was induced by streptozotocin (60 mg/kg, i.p.). Twelve weeks after diabetes induction, rats were decapitated. Malondialdehyde, glutathione, sialic acid and nitric oxide levels, superoxide dismutase, catalase, glutathione-S-transferase, myeloperoxidase, and tissue factor activities were determined in brain tissue. Melatonin alone showed its antioxidant effect by increasing brain glutathione level, superoxide dismutase, catalase, and glutathione-S-transferase activities and decreasing malondialdehyde level in experimental diabetes. Although insulin did not have a significant effect on glutathione and glutathione-S-transferase, its effects on lipid peroxidation, superoxide dismutase, and catalase were similar to melatonin; insulin also decreased myolopeoxidase activity and increased tissue factor activity. Combined melatonin and insulin treatment mimicked the effects of insulin. Conclusion Addition of melatonin to the insulin treatment did not change the effects of insulin, but the detailed role of melatonin alone in the treatment of diabetes merits further experimental and clinical investigation.Publication Metadata only Intravesical hyaluronic acid treatment improves bacterial cystitis and reduces cystitis-induced hypercontractility in rats(WILEY, 2015) YEGEN, BERRAK; Yildiz, Nurdan; Alpay, Harika; Tugtepe, Halil; Kumral, Zarife Nigar Ozdemir; Akakin, Dilek; Ilki, Arzu; Sener, Goksel; Yegen, Berrak C.ObjectiveTo investigate the effect of intravesical hyaluronic acid on Escherichia coli-induced cystitis and cystitis-induced hypercontractility in rats. MethodsBacterial cystitis was induced in Wistar female rats by intravesical inoculation of E.coli. Isotonic saline was instilled in the control group (n=6). The rats were either non-treated, treated with gentamycin (4mg/kg, 5days) or treated intravesically with hyaluronic acid (0.5mL, 0.5%). On the eighth day, the bladder tissues were excised for histological examination, and the measurements of myeloperoxidase, superoxide dismutase and catalase activities. Contraction/relaxation responses to carbachol, isoprotrenol and papaverine were studied. ResultsTissue myeloperoxidase activity was increased, but superoxide dismutase and catalase activities were decreased in bacterial cystitis, while hyaluronic acid treatment reversed these changes. In the hyaluronic acid-treated group, healing of the uroepithelium was observed, while decreased inflammatory cell infiltration was obvious in gentamycin-treated group. E.coli-induced cystitis in all rats resulted in increased contraction responses to carbachol compared with controls (P<0.01). Treatment with hyaluronic acid, but not gentamycin, significantly (P<0.05) depressed hypercontractility at maximum carbachol concentrations. In all rats with cystitis, papaverine-induced relaxation was increased, whereas isoproterenol-induced relaxation curves were not different between the studied groups. ConclusionGentamycin treatment, despite its ameliorative effect on inflammation, had no impact on the contractile dysfunction of the injured bladder. Intravesical hyaluronic acid, in addition to its supportive role in the healing of the epithelium, seems to lower the increased threshold for contraction and to reduce oxidative stress. These findings support a potential role for hyaluronic acid in the treatment of bacterial cystitis.Publication Open Access Neuroprotective Effects of Alpha-Lipoic Acid in Experimental Spinal Cord Injury in Rats(TAYLOR & FRANCIS LTD, 2010-01) VELİOĞLU ÖĞÜNÇ, AYLİZ; Toklu, Hale Z.; Hakan, Tayfun; Celik, Hasan; Biber, Necat; Erzik, Can; Ogunc, Ayliz V.; Akakin, Dilek; Cikler, Esra; Cetinel, Sule; Ersahin, Mehmet; Sener, GokselBackground: Oxidative stress is a mediator of secondary injury to the spinal cord following trauma. Objective: To investigate the putative neuroprotective effect of a-lipoic acid (LA), a powerful antioxidant, in a rat model of spinal cord injury (SCI). Methods: Wistar albino rats were divided as control, vehicle-treated SCI, and LA-treated SCI groups. To induce SCI, a standard weight-drop method that induced a moderately severe injury (100 g/cm force) at T10 was used. Injured animals were given either 50 mg/kg LA or saline at 30 minutes postinjury by intraperitoneal injection. At 7 days postinjury, neurologic examination was performed, and rats were decapitated. Spinal cord samples were taken for histologic examination or determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity, and DNA fragmentation. Formation of reactive oxygen species in spinal cord tissue samples was monitored by using a chemiluminescence (CL) technique. Results: SCI caused a significant decrease in spinal cord GSH content, which was accompanied with significant increases in luminol CL and MDA levels, MPO activity, and DNA damage. Furthermore, LA treatment reversed all these biochemical parameters as well as SO-induced histopathologic alterations. Conversely, impairment of the neurologic function caused by SCI remained unchanged. Conclusion: The present study suggests that LA reduces SCI-induced oxidative stress and exerts neuroprotection by inhibiting lipid peroxidation, glutathione depletion, and DNA fragmentation.Publication Metadata only Ameliorative effects of riboflavin on acetic acid-induced colonic injury in rats(WILEY, 2018) ERTAŞ, BÜŞRA; Karakoyun, Berna; Ertas, Busra; Yuksel, Meral; Akakin, Dilek; Cevik, Ozge; Sener, GokselRiboflavin (RF) has been found to be a promising antioxidant and/or anti-inflammatory agent in several studies. However, the effect of RF against acetic acid (AA)-induced colonic injury is currently unknown. This study aimed to investigate the potential antioxidant and protective effects of RF in a rat model of ulcerative colitis. Starting immediately after the colitis induction (AA+RF group) or 1week before the colitis induction (RF+AA+RF group), the rats were treated with RF (25mg/kg per day; p.o.) for 3days. The control and AA groups received saline (1mL; p.o.) whereas AA+SS group (positive control) received sulfasalazine (100mg/kg per day; p.o.) for 3days. Colonic samples were taken for the biochemical and histological assessments on the third day. High damage scores, elevated tissue wet weight index (WI), tissue myeloperoxidase (MPO) activity, 8-hydroxy-2-deoxyguanosine levels and chemiluminescence values, and a pronounced decrease in antioxidant glutathione (GSH) levels of the AA group were all reversed by RF pretreatment (RF+AA+RF group) and SS treatment (AA+SS group) (P<.05-.001). Tissue WI, MPO activity and GSH levels were not statistically changed in the AA+RF group. Western blot analysis revealed that the decreased protein expressions of tissue collagen (COL) 1A1, COL3A1 and transforming growth factor-1 in the AA group were elevated in all the treatment groups (P<.05-.001). In conclusion, RF exerts both the antioxidant and anti-inflammatory effects against AA-induced colonic inflammation by suppressing neutrophil accumulation, inhibiting reactive oxidant generation, preserving endogenous glutathione, improving oxidative DNA damage and regulating inflammatory mediators, suggesting a future potential role in the treatment and prevention of ulcerative colitis.Publication Metadata only Protective effect of exercise and sildenafil on acute stress and cognitive function(PERGAMON-ELSEVIER SCIENCE LTD, 2015) AKAKIN, DİLEK; Ozbeyli, Dilek; Gokalp, Ayse Gizem; Koral, Tolga; Ocal, Onur Yuksel; Dogan, Berkay; Akakin, Dilek; Yuksel, Meral; Kasimay, OzgurIntroduction: There are contradictory results about the effects of exercise and sildenafil on cognitive functions. Aim: To investigate the effects of sildenafil pretreatment and chronic exercise on anxiety and cognitive functions. Method: Wistar rats (n = 42) were divided as sedentary and exercise groups. A moderate-intensity swimming exercise was performed for 6 weeks, 5 days/week, 1 h/day. Some of the rats were administered orogastrically with sildenafil (25 mg/kg/day) either acutely or chronically. Exposure to cat odor was used for induction of stress. The level of anxiety was evaluated by elevated plus maze test, while object recognition test was used to determine cognitive functions. Brain tissues were removed for the measurement of myeloperoxidase (MPO), malondialdehyde (MDA), nitric oxide levels, lucigenin-enhanced chemiluminescence, and for histological analysis. Results: Increased MPO and MDA levels in sedentary-stressed rats were decreased with sildenafil applications. Chronic exercise inhibited the increase in MPO levels. Increased nitric oxide and lucigenin chemiluminescence levels in sedentary-stressed rats, were diminished with chronic sildenafil pretreatment. The time spent in the open arms of the plus maze was declined in sedentary-stressed rats, while chronic sildenafil pretreatment increased the time back to that in non-stressed rats. Acute sildenafil application to exercised rats prolonged the time spent in open arms as compared to non-treated exercise group. The time spent with the novel object, which was decreased in sedentary-stressed rats, was increased with sildenafil pretreatment. Our results suggest that sildenafil pretreatment or exercise exerts a protective effect against acute stress and improves cognitive functions by decreasing oxidative damage. (C) 2015 Elsevier Inc All rights reserved.Publication Metadata only Protective effect of alpha-lipoic acid, aerobic or resistance exercise from colitis in second hand smoke exposed young rats(WILEY, 2017) AKAKIN, DİLEK; Ozbeyli, Dilek; Berberoglu, Ayse Cansu; Ozen, Anil; Erkan, Oktay; Basar, Yunus; Sen, Tunahan; Akakin, Dilek; Yuksel, Meral; Cakir, Ozgur KasimayThe role of second hand smoke (SHS) exposure on ulcerative colitis is not known. Our aim was to examine the effects of -lipoic acid (ALA), chronic aerobic (AE) or resistance exercise (RE) on SHS exposed rats with colitis. Sprague-Dawley male rats (150-200g, n=54) were selected for colitis induction. Among the colitis groups, one group was exposed to SHS (6d/wk, 4cigarettes/d) and the other was not. The SHS group was divided into subgroups as follows: sedentary; AE (swimming; 3d/wk); and RE (climbing with weight; 3d/wk). After 5weeks, colitis was induced by intrarectal acetic acid. All groups had subgroups that were given subcutaneously ALA (50mg/kg per day) or vehicle for 3days. Following decapitation, colon tissues were sampled to examine malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity, luminol and lucigenin chemiluminenscence, macroscopic scoring and histologic examination. ANOVA and Student's t-test were used for statistical analysis. The increased macroscopic and microscopic scores, MPO, MDA, luminol and lucigenin measurements in colitis and SHS-colitis groups were decreased via ALA (P<.05-.001). AE declined macroscopic and microscopic scores, MDA, lucigenin compared to colitis and SHS-colitis groups (P<.01-.001). RE reduced microscopic score, MPO, MDA, luminol, lucigenin (P<.05-.001) that were increased with colitis. Decreased GSH levels (P<.01) in the SHS-colitis group approached to control levels when given ALA. According to our results SHS and colitis induction increased inflammatory damage. SHS did not worsen it more than colitis. Our results suggest that ALA, AE or RE might be protective for SHS exposed ulcerative colitis conditions.