Moleküler Biyoloji ve Genetik Bölümü / Department of Molecular Biology and Genetics
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Browsing Moleküler Biyoloji ve Genetik Bölümü / Department of Molecular Biology and Genetics by Author "Akdemir, Osman"
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Publication Calpain inhibitor AK 295 inhibits calpain-induced apoptosis and improves neurologic function after traumatic spinal cord injury in rats(Soc Espanola Neurocirugia, C/O Dr Poza, Gran Via Salzillo 42, 30005 Murcia, Spain, 2009-06) Çolak, Ahmet; Kaya, Mehmet; Karaoğlan, Alper; Sağmanlıgil, Ayhan; Akdemir, Osman; Şahan, Elife; ÇELİK, ÖZGE; TR113987; TR110929Background. An increase in the level of intracellular calcium activates the calcium-dependent neutral protease calpain, which in turn leads to cellular dysfunction and cell death after an insult to the central nervous system. fit this study, we evaluated the effect of a calpain inhibitor, AK 295, on spinal cord structure, neurologic function, and apoptosis after spinal cord injury (SCI) in a murine model. Methods. Thirty albino Wistar rats were divided into 3 groups of 10 each: the sham-operated control group (group 1), the spinal cord trauma group (group 2), and the spinal cord trauma plus AK 295 treatment group (group 3). After having received a combination of ketamine 60 mg/kg and xylazine 9 mg/kg to induce anesthesia, the rats in groups 2 and 3 were subjected to thoracic trauma by the weight drop technique (40 g-cm). One hour after having been subjected to that trauma, the rats in groups 2 and 3 were treated with an intraperitoneal injection of either dimethyl sulfoxide 2 mg/kg or AK 295 2 mg/kg. The effects of the injury and the efficacy of AK 295 were determined by an assessment of the TUNEL technique and the results of examination with a light microscope. The neurologic performance of 5 rats from group 2 and 5 from group 3 was assessed by means of the inclined plane technique and the modified Tarlov's motor grading scale 1, 3, and 5 days after spinal cord trauma. Findings. Light-microscopic examination of spinal cord specimens from group 2 revealed hemorrhage, edema, necrosis, and vascular thrombi 24 : hours after trauma. Similar (but less prominent) features were seen in specimens obtained from group 3 rats. Twenty-four hours after injury, the mean apoptotie cell numbers in groups I and 2 were zero and 4.57 +/- 0.37 cells, respectively. In group 3, the mean apoptotic cell number was 2.30 +/- 0.34 cells, a value significantly lower than that in group 2 (P < .05). Five days after trauma, the injured rats in group 2 demonstrated significant motor dysfunction (P < .05). In comparison, the motor scores exhibited by group 3 rats were markedly better (P < .05). Conclusions. AK 295 inhibited apoptosis via calpain-dependent pathway's and provided neuroprotection and improved neurologic function in a rat model of SCI. To our knowledge, this is the first study to evaluate the use of AK 295, a calpain inhibitor, after SCI. Our data suggest that AK 295 might be a novel therapeutic compound for the neuroprotection of tissue and the recovery of function in patients with a SCI.Publication Q-VD-OPh, a pancaspase inhibitor, reduces trauma-induced apoptosis and improves the recovery of hind-limb function in rats after spinal cord injury(Soc Espanola Neurocirugia, C/O Dr Poza, Gran Via Salzillo 42, 30005 Murcia, Spain, 2009-12) Colak, A.; Antar, Veysel; Karaoğlan, Alper; Akdemir, Osman; Şahan, E.; Sagmanlıgil, Ayhan; ÇELİK, ÖZGE; 110929Background. Various caspases have been implicated in the development of secondary damage after spinal cord injury (SCI). Anticaspase therapy that targets only one caspase has been investigated in a variety of in vitro and in vivo studies. This study examined the neuroprotective effects of Q-VD-OPh, a pan-caspase inhibitor, in a rat model of SCI. Methods. Thirty Wistar albino rats were divided into 3 groups of 10 each: the sham-operated controls (group 1), the trauma-created controls (group 2), and the Q-VD-OPh-treated rats (group 3). An SCI (a trauma of 40 g-cm) was produced at the thoracic level (T8-T10) by the weight-drop technique. The response to injury and the neuroprotective effects of Q-VD-OPh were investigated by histopathologic examination and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) 24 hours and 5 days after trauma. The inclined plane technique of Rivlin and Tator and a modified version of Tarlov's grading scale were used to assess the functional status of the rats 24 hours, 3 days, and 5 days after injury. Results. Twenty-four hours after trauma, light microscopic examination of a specimen taken from group 2 rats revealed hemorrhage, necrosis, vascular thrombi, and edema. Group 3 tissue samples showed similar features at that time. Twenty-four hours after trauma, the mean apoptotic cell number was 4.47 +/- 0.35 cells in group 2 and 1.58 +/- 0.33 in group 3. Five days after injury, the mean apoptotic cell count was 4.35 +/- 0.47 in group 2 and 1.25 +/- 0.34 in group 3. Thus the number of TUNEL-positive cells in an injured spinal cord was greatly reduced by treatment with Q-VD-OPh. The neurologic function scores (both the inclined plane performance and motor grading scores) were significantly better in the Q-VD-OPh-treated group than in the trauma-created control group. Conclusion. The marked antiapoptotic properties of Q-VD-OPh due to the inhibition of all caspases render it a promising novel agent. A therapeutic strategy using Q-VD-OPh may eventually lead to the effective treatment of SCI in humans.Publication Tauroursodeoxycholic acid and secondary damage after spinal cord injury in rats(CHURCHILL LIVINGSTONE, JOURNAL PRODUCTION DEPT, ROBERT STEVENSON HOUSE, 1-3 BAXTERS PLACE, LEITH WALK, EDINBURGH EH1 3AF, MIDLOTHIAN, SCOTLAND, 2008-06) Çolak, Ahmet; Kelten, Bilal; Sağmanlıgil, Ayhan; Akdemir, Osman; Karaoğlan, Alper; Şahan, Elife; Barut, Şeref; ÇELİK, ÖZGE; TR110561; TR110929; TR113987Greater clinical understanding of the pivotal role of apoptosis in spinal cord injury (SCI) has led to new and innovative apoptosisbased therapies for patients with an SCL Tauroursodeoxycholic acid (TUDCA) is a biliary acid with antiapoptotic properties. To our knowledge, this is the first study in the English language to evaluate the therapeutic efficacy of TUDCA in an experimental model of SCI. Thirty rats were randomized into three groups (sham-operated, trauma only, and trauma plus TUDCA treatment) of 10 each. In groups 2 and 3, spinal cord trauma was produced at the T8-T10 level via the Allen weight drop technique. Rats in group 3 were treated with TUDCA (200 mg/kg intraperitoneal) 1 min after trauma. The rats were killed either 24 h or 5 days after injury. The neuroprotective effect of TUDCA on injured spinal cord tissue and the effects of that agent on the recovery of hind-limb function were assessed. The efficacy of treatment was evaluated with histopathologic examination and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) analysis. Histopathologic characteristics were analyzed by comparison of hematoxylin-and-eosin stained specimens. Neurologic evaluations were performed 24 h, 3 days, and 5 days after trauma. Hind-limb function was assessed with the inclined plane technique of Rivlin and Tator and the modified version of Tarlov's grading scale. Twenty-four hours after injury, there was a significantly higher number of apoptotic cells in the lesioned spinal cord group than in the sham-operated control group. Treatment of the rats with TUDCA significantly reduced the number of apoptotic cells (4.52 +/- 0.30 vs. 2.31 +/- 0.24 in group 2) and the degree of tissue injury. Histopathologic examination showed that group 3 rats had better spinal cord architecture compared with group 2 rats. Five days after injury, the mean inclined plane angles in groups 1, 2, and 3 were 65.50 degrees +/- 2.09, 42.00 degrees +/- 2.74, and 53.50 degrees +/- 1.36. Motor grading of the rats revealed a similar trend. These differences were statistically significant (p < 0.05). The mechanism of neuroprotection in the treated rats, although not yet elucidated, may be related to the marked antiapoptotic properties of TUDCA. A therapeutic strategy using TUDCA may eventually lead to effective treatment of SCI without toxic effects in humans. (C) 2007 Elsevier Ltd. All rights reserved.