Browsing by Author "Seker, Ayse"

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Evaluation of the Effects of Intermittent Fasting Diet and Capsaicin Treatment on the Survival of Laser Damaged Drg Neurons in Experimental Obesity Model
(Wiley, 2022) Seker, Ayse; Kaya, Mehmet Salih; Ustun, Ramazan
Functional and Structural Neurodegenerative Activities of Ankaferd Bloodstopper in a Mouse Sciatic Nerve Model
(Spandidos Publ Ltd, 2024) Ustun, Ramazan; Oguz, Elif Kaval; Seker, Ayse; Taspinar, Filiz
Traumatic and postoperative hemorrhages are life-threatening complications. Ankaferd BloodStopper (ABS) is a potent topical hemostatic agent to stop bleeding. However, ABS is associated with nerve toxicity. The present study aimed to investigate the functional and structural neurodegenerative effects of ABS in a mouse model. A total of 30 male BALB/c mice, aged 6-8 weeks, were randomly divided into control group (no treatment), a sham group (treated with saline) and an experimental group (treated with ABS). In the saline and the ABS groups, the right sciatic nerve was surgically exposed and treated with saline or ABS, respectively. No surgical procedure was performed in the control group. On day 7 post-treatment, functional changes of the sciatic nerve were evaluated by a horizontal ladder rung walking task. Structural changes were assessed with immunohistochemistry. In the horizontal ladder rung walking test, the gait impairment was proportional to the severity of sciatic nerve damage, with the ABS group showing a significantly higher rate of errors than the control and saline groups. Immunohistochemistry demonstrated extensive degeneration and deformation in the axons and myelin sheath of the sciatic nerve in the ABS group. The results provide compelling evidence for the neurotoxicity of ABS.
Neuromuscular Degenerative Effects of Ankaferd Blood Stopper® in Mouse Sciatic Nerve Model
(Taylor & Francis Ltd, 2017) Ustun, Ramazan; Oguz, Elif Kaval; Delilbasi, Cagri; Seker, Ayse; Taspinar, Filiz; Oncu, Mehmet Resit; Oguz, Ahmet Regaip
Purpose: Ankaferd Blood Stopper((R)) (ABS), a licenced medicinal herbal extract, is commonly used as an effective topical haemostatic agent. This study is designed to investigate whether topical ABS application may cause peripheral nerve degeneration and neuromuscular dysfunction in a mouse sciatic nerve model.Methods: Twenty mice were randomly divided into two groups; an ABS treated experimental group and a saline-treated control group. Left sciatic nerves were treated with 0.3ml of ABS in the experimental group and 0.3ml of sterile saline in the control group for 5min. Peripheral nerve degeneration and neuromuscular dysfunction were evaluated by behavioural tests, electrophysiological analysis and weight ratio comparison of target muscles.Results: The motor function, assessed by the sciatic function index, was significantly impaired in ABS-treated animals as compared to the animals treated with saline. Motor coordination, evaluated with the rotarod test, was significantly decreased (-42%) in ABS-treated animals compared to the saline-treated animals. The degree of pain, assessed by the reaction latency to thermal stimuli (hot-plate test), was significantly prolonged (313%) in ABS-treated mice when compared to the saline-treated mice. ABS-treated mice showed a significant reduction in motor nerve conduction velocity (MNCV) (-52%) and the compound muscle action potential (CMAP) (-47%); however, it significantly prolonged onset latency (23%). The gastrocnemius muscles weight ratio of the ABS group was considerably lower than that of the control group.Conclusions: These findings demonstrate that ABS triggers peripheral nerve degeneration and functional impairment and, thus promotes a deterioration of sciatic nerves.
Serum Paraoxonase Activity and Oxidative Status in Subjects With Alopecia Areata
(Taylor & Francis Ltd, 2013) Bilgili, Serap Gunes; Ozkol, Halil; Karadag, Ayse Serap; Ozkol, Hatice Uce; Seker, Ayse; Calka, Omer; Aslan, Mehmet
Introduction: Previous studies have suggested that oxidative stress may play an important role in the pathogenesis of alopecia areata (AA) but these reports are limited and conflicting. Objectives: The aim of this study was to investigate serum paraoxonase-1 (PON1) activity and oxidative status in subjects with AA. Materials and methods: Thirty-nine subjects with AA and 39 healthy controls were enrolled. Serum PON1 activity, total antioxidant capacity (TAC), total oxidant status (TOS) and oxidative stress index (OSI) were determined. Results: Serum TAC levels and PON1 activity were significantly lower in the subjects with AA than controls (p=0.038, p=0.001, respectively), whereas TOS levels and OSI were significantly higher (both, p=0.001) in the subjects with AA. Conclusions: Our results suggest that reduced PON1 activity may be related to increased oxidant and decreased antioxidant levels. These data indicated that oxidant/antioxidant imbalance may play a role in the etiopathogenesis of AA.
Thymoquinone Prevents Cisplatin Neurotoxicity in Primary Drg Neurons
(Elsevier Science Bv, 2018) Ustun, Ramazan; Oguz, Elif Kaval; Seker, Ayse; Korkaya, Hasan
Chemotherapy-induced peripheral neuropathy (CIPN) is a substantial, dose-limiting adverse effect that occurs in cancer patients. Cis-dichlorodiamine (II) platinum (CDDP, cisplatin) is a platinum-based chemotherapeutic agent that causes severe acute and chronic peripheral neuropathies in 30% of cancer patients. Thymoquinone (TQ), a leading bioactive constituent of Nigella sativa seeds, has been reported to have antioxidant, anti-inflammatory, anti-neoplastic and neuroprotective properties. Dorsal root ganglia (DRG) include different classes of primary sensory neurons, such as nociceptors, mechanoreceptors, and proprioceptive neurons. Here, we investigated the neuroprotective activity of TQ against cisplatin neurotoxicity in cultured DRG neurons. We prepared neuronal cultures from DRGs of adult mice, pre-treated them with or without varying doses of TQ prior to exposure of cells to cisplatin. The preparations were viewed under the scope before and after the treatment at 24 h, 48 h, and 72 h time points. We analyzed neuronal cell viability and neurite outgrowths, and evaluated morphologic changes of neuronal or non-neuronal cells. TQ significantly increases the ability to extend neurites and neuronal cell viability when compared to the culture conditions which were treated with cisplatin only. Although we provide compelling evidence for the protective activity of TQ against chemotherapy-induced neurotoxicity, further detailed investigations in preclinical settings are warranted for its clinical use.
Thymoquinone Protects Drg Neurons From Axotomy-Induced Cell Death
(Taylor & Francis Ltd, 2018) Ustun, Ramazan; Oguz, Elif Kaval; Seker, Ayse; Korkaya, Hasan
Objective: Peripheral nerve injury (PNI) is a significant health problem that is linked to sensory, motor, and autonomic deficits. This pathological condition leads to a reduced quality of life in most affected individuals. Schwann cells (SCs) play a crucial role in the repair of PNI. Effective agents that promote SC activation may facilitate and accelerate peripheral nerve repair. Thymoquinone (TQ), a bioactive component of Nigella sativa seeds, has an antioxidant, anti-inflammatory, immunomodulatory, and neuroprotective properties. In the present study, the neuroprotective efficacy of TQ was investigated by using a laser microdissection technique in a mouse PNI model. Methods: Single cells were isolated from dorsal root ganglions (DRGs) of 6-8-week-old mice, maintained in defined culture conditions and treated with or without TQ at different concentrations. Axons were cut (axotomy) using a controllable laser microbeam to model axonal injury in vitro. Under fluorescence microscopy, cell viability was evaluated using the fluorescent dyes. The behavior of the cells was continuously monitored with time-lapse video microscopy. Results: TQ significantly increased neuronal survival by promoting the survival and proliferation of SCs and fibroblasts, as well as the migration of SCs. Furthermore, TQ improved the ability to extend neurites of axotomized neurons. The regenerative effect of TQ was dose-dependent suggesting a target specificity. Our studies warrant further preclinical and clinical investigations of TQ as a potential regenerative agent to treat peripheral nerve injuries. Conclusion: TQ exhibits a regenerative potential for the treatment of damaged peripheral nerves.