Aslı Aykaç

The change in muscarinic receptor subtypes in different brain regions of rats treated with fluoxetine or propranolol in a model of post-traumatic stress disorder

This study shows the possible contribution of muscarinic receptors in the pathophysiology of post-traumatic stress disorder. Sprague-Dawley rats of both sexes were exposed to dirty cat litter (trauma) for 10 min and the protocol was repeated 1 week later with a trauma reminder (clean litter). The rats also received intraperitoneal fluoxetine (2.5, 5 or 10 mg/kg/day), propranolol (10 mg/kg/day) or saline for 7 days between two exposure sessions. Functional behavioral experiments were performed using elevated plus maze, following exposure to trauma reminder. Western blot analyses for M(1), M(2), M(3), M(4) and M(5) receptor proteins were employed in the homogenates of the hippocampus, the frontal cortex and the amygdaloid complex. The anxiety indices increased from 0.63±0.02 to 0.89±0.04 in rats exposed to the trauma reminder. The freezing times were also recorded as 47±6 and 133±12 s, in control and test animals respectively. Fluoxetine or propranolol treatments restored the increases in the anxiety indices and the freezing times. Female rats had higher anxiety indices compared to males. Western blot data showed increases in M(2) and M(5) expression in the frontal cortex. Expression of M(1) receptors increased and M(4) subtype decreased in the hippocampus. In the amygdaloid complex of rats, we also detected a down-regulation of M(4) receptors. Fluoxetine and propranolol only corrected the changes occurred in the frontal cortex. These results may imply that muscarinic receptors are involved in this experimental model of post-traumatic stress disorder.

D-Cycloserine acts via increasing the GluN1 protein expressions in the frontal cortex and decreases the avoidance and risk assessment behaviors in a rat traumatic stress model.

D-cycloserine (DCS), an FDA approved anti-tuberculosis drug has extensively been studied for its cognitive enhancer effects in psychiatric disorders. DCS may enhance the effects of fear extinction trainings in animals during exposure therapy and hence we investigated the effects of DCS on distinct behavioral parameters in a predator odor stress model and tested the optimal duration for repeated daily administrations of the agent. Cat fur odor blocks were used to produce stress and avoidance and risk assessment behavioral parameters were used where DCS or saline were used as treatments in adjunct to extinction trainings. We observed that DCS facilitated extinction training by providing further extinction of avoidance responses, risk assessment behaviors and increased the contact with the cue in a setting where DCS was administered before extinction trainings for 3 days without producing a significant tolerance. In amygdala and hippocampus, GluN1 protein expressions decreased 72h after the fear conditioning in the traumatic stress group suggesting a possible down-regulation of NMDARs. We observed that extinction learning increased GluN1 proteins both in the amygdaloid complex and the dorsal hippocampus of the rats receiving extinction training or extinction training with DCS. Our findings also indicate that DCS with extinction training increased GluN1 protein levels in the frontal cortex. We may suggest that action of DCS relies on enhancement of the consolidation of fear extinction in the frontal cortex.

Protective effect of silk fibroin in burn injury in rat model

Activation of pro-inflamatuar pathways play major role in formation of major complications as a result of burns. This study was planned to investigate the protective effect of Silk Fibroin in lung injury caused by burn in the experimental rat model. After rinsing the skin of rats under ether anesthesia, the exposed back region, covers 30% of the total body, was kept in the 90°C water bath for 10s. The control rats were kept in the 25°C water bath for 10s. Immediately after burning process, silk fibroin was administered orally at a dose of 600mg/kg. After 24h following burning from all groups the levels of TNF-α, IL-1β in blood samples and the MDA, GSH and the activity of MPO were determined from taken lung tissues. Moreover, the expression of Bcl-2/Bax, Caspase-3 and Caspase-9 were determined. Significant increase in TNF-α, IL-1β, Casp-3 and Casp-9 levels were observed in the Silk Fibroin-treated burn group (p<0.05) whereas for ratio of Bcl-2/Bax, a significant reduction was observed compared to control group (p<0.05). Increased levels of TNF-α, IL-1β, Caspase-3 and Caspase-9 in Silk Fibroin-treated burn groups were found to be reversed. Silk fibroin can be an effective biomaterial in diminishing burn injury in tissue and apoptosis.

Protective effects of St. John’s wort in the hepatic ischemia/reperfusion injury in rats

OBJECTIVESnThe purpose of this study was to investigate possible protective effects of St. Johns wort in the hepatic ischemia/reperfusion injury.nnnMATERIAL AND METHODSnThe hepatic artery, portal vein, and bile duct were all clamped for 45 minutes to induce ischemia in rats, and after that reperfusion for 1 hour. SJW was administrated orally, once a day for 3 days before ischemia/reperfusion. The aspartate aminotransferase, alanine aminotransferase, tumor necrosis factor, and interleukin levels were measured in the serum samples. Luminol chemiluminescence, lucigenin luminol chemiluminescence levels; myeloperoxidase. The sodium-potassium ATPase (Na+/K+ ATPase) activity was determined in the liver tissue, and caspase-3 and caspase-9 activity with the bcl-2/bax ratio were measured by the western blot analysis.nnnRESULTSnThe St. Johns wort administration recovered the aspartate aminotransferase, alanine aminotransferase, tumor necrosis factor, and IL-1β levels serum parameters meaningfully, while ischemia/reperfusion caused an increase in luminol chemiluminescence, lucigenin luminol chemiluminescence, myeloperoxidase, caspase-3, and caspase-9 activity and led to a decrease in the B-cell lymphoma-2/bcl-2-associated X protein (bcl-2/bax) ratio and the Na+/K+ ATPase activity.nnnCONCLUSIONnThe obtained results indicate protective effects of St. Johns wort on the ischemia/reperfusion injury through various mechanisms, and we are able to suggest that St. Johns wort can clinically create a new therapeutic principle.

The effects of citalopram and low-dose risperidone on memory and anxiety in rats subjected to chronic immobilization stress

ABSTRACT OBJECTIVES: Many clinical reports describe the beneficial effects of low-dose atypical antipsychotic added to the antidepressants in the management of anxiety disorders. The aim of this study was to evaluate the effect of low-dose atypical antipsychotic when added to antidepressant treatment on cholinergic M1 receptor expression in the hippocampus and amygdale region in learning and cognitive disorders caused by anxiety. METHODS: The treatments were administered by using different test models on memory, learning, and anxiety, as well as the effect on muscarinic M1 receptor expression levels were assessed. Citalopram (10u2005mg/kg/sc) and combination [citalopram and risperidone (1u2005mg/kg/sc)] treatments were applied after stress induction using the immobilization model in rats. Animals groups were randomly divided as: control, stress, stressu2009+u2009citalopram, and stressu2009+u2009combination treatment group. Rats in stress groups were immobilized in cages for 4u2005h a day for 15 days. On days 1–5, groups were subjected to Morris water maze (MWM), open field, and elevated plus maze (EPM) tests. RESULTS: MWM test results have shown that citalopram induces an anxiolytic effect. Low-dose risperidone treatment has increased the antidepressant-like activity of citalopram in all tests. In OFT the number of squares that rats were circulating on the plane was increased and the time spent by the rats on the maze platform was also increased in MWM. In addition to this, the time spent by the rats on the open arms of the EPM test were also increased. Since the combined treatment increased the discovery of the environment and the active behaviour in tests; all those reflected the increase in general activity. Findings also suggest that treatments may play an effective role in altering the expression level of M1 receptors which are effective in learning and recalling information in the amygdale and the hippocampus. Combination treatment has been shown to provide a meaningful correction of stress-induced memory and learning functions. CONCLUSIONS: These findings indicate that combination treatment may help reduce the stress-induced impairments in cognitive functions.

Potential protective effects of silk fibroin against ethanol induced gastric ulcer

ABSTRACT: Ulcers that develop due to alcohol consumption are frequently confronted. The aim of this study was to investigate the protective effects of silk fibroin on the pro-apoptotic and anti-apoptotic protein expression levels on ethanol induced-ulcer models in rats. For three consecutive days, orogastrically either silk fibroin or saline were given to rats. On the 4th day, animals were deprived of food but allowed free access to water for 24 h before the experiment. While control groups were treated with only physiological saline, the ulcer groups were treated orally either with saline or silk fibroin groups. For ulcer induction, 1 ml of absolute ethanol by gavage were given to both group. Firstly, intracardiac blood was taken at 60 min of EtOH or saline administration and immediately animals were decapitated. In blood samples, the amount of TNF-uf061, IL-1β were analysed whereas in stomach tissues, the levels of MDA, GSH, and MPO activity and the expression levels of bcl-2, Bax, caspase-3 and -9 were determined. In ulcer groups, the amount of TNF-uf061 , IL-1β, MDA, MPO, caspase-3 and caspase-9 were found to be significantly higher compared to control groups whereas in GSH, Bcl-2/Bax were found to be lower (p < 0.005). In treatment groups it is observed that silk fibroin recovers the amount of TNF-uf061, IL 1-β, MDA, MPO, GSH, caspase-3, caspase-9, and Bcl2/Bax. In conclusion, for the treatment of the gastric ulcer SF thought to be very efficient therapeutic agent.

Post-Traumatic Stress Disorder: The Importance of Apoptosis

Sorumlu Yazar/Correspondence Author: Aslı Aykaç E-posta/E-mail: aykacasli@yahoo.com Geliş Tarihi/Received: 18.04.2016 Kabul Tarihi/Accepted: 26.08.2016 Çevrimiçi Yayın Tarihi/Available Online Date: 01.11.2016 DOI: 10.5152/clinexphealthsci.2016.76 ©Telif Hakkı 2016 Marmara Üniversitesi Sağlık Bilimleri Enstitüsü Makale metnine www.clinexphealthsci.com web sayfasından ulaşılabilir ©Copyright by 2016 Journal of Marmara University Institute of Health Sciences Available online at www.clinexphealthsci.com Öz Abstract

Altered ratio of proapoptotic and antiapoptotic proteins in different brain regions of female rats in model of post-traumatic stress disorder (Post-travmatik stres hastaliği modelinde dişi siçanlarin farkli beyin bölgelerinde proapoptotik ve antiapoptotik proteinlerin oranindaki değişim)

Abstract Objective: The B-cell lymphoma/leukemia-2 (Bcl-2) family of proteins governs mitochondrial membrane permeability where the programmed apoptotic process is controlled by the balance between proapoptotic (Bax) and antiapoptotic (Bcl-2) proteins. We aimed to investigate the [Bcl-2]/[Bax] in different brain regions in a post-traumatic stress disorder rat model. Methods: Female Sprague-Dawley rats were exposed to dirty cat litter (trauma) for 10 min and the protocol was repeated 1 week later with a trauma reminder (clean litter) in reversed 12 h light/dark cycle. The rats received intraperitoneal saline, fluoxetine (2.5 mg/kg/day) or propranolol (10 mg/kg/day) for 7 days between exposure sessions. Following exposure to the trauma reminder, elevated plus maze experiments were done. Immunoblotting was used to quantify [Bcl-2] and [Bax] proteins in the homogenates of the dorsal hippocampus, the frontal cortex and the amygdaloid complex. Results: Fluoxetine reversed the increases in the anxiety indices and the freezing times. In the amygdaloid complex and the frontal cortex, the [Bcl-2]/[Bax] decreased in the traumatized control rats significantly (p<0.0001), but not in the dorsal hippocampus. Although the fluoxetine treatment reversed the apoptotic changes but propranolol failed and caused proapoptotic proteins to increase. Conclusion: These results may suggest a neuroprotective role for fluoxetine but not for propranolol. Özet Amaç: B-hücre lenfoma/lösemi-2 (Bcl-2) protein ailesi, proapoptotik (Bax) ve antiapoptotik (Bcl-2) proteinleri arasındaki denge ile kontrol edilen programlı hücre ölümü işleminde mitokondri zar geçirgenliğini düzenlemektedir. Post travmatik stress sıçan modelinde farklı beyin bölgelerinde [Bcl-2]/[Bax] oranını araştırmayı amaçlıyoruz. Metod: Dişi Sprague-Dawley sıçanlar ters 12 s aydınlık/karanlık siklusunda 10 dak. kirli kedi kumuna maruz bırakıldı ve protokol 1 hafta sonra travma çağrıştırıcı (temiz kum) ile tekrarlandı. Sıçanlara intraperitonel tuzlu su, fluoksetin (2.5 mg/kg/day) veya propronolol (10 mg/ kg/gün) uygulama dönemleri arasında 7 gün verildi. Travma çağrıştırıcıya maruz bırakmanın ardından yükseltilmiş artı labirent yapıldı. Western blot dorsal hipokampus, frontal korteks ve amigdalar bölge homojenatlarında Bcl-2 ve Bax proteinlerinin miktarını belirlemede kullanıldı. Bulgular: Fluoksetin, ankisiyete indeksleri ve dona kalma sürelerindeki artışları geri çevirdi. Amigdalar bölgede ve frontal korteks de [Bcl-2]/[Bax] oranı travmatik kontrol sıçanlarda anlamlı olarak azaldı (p<0.0001), fakat dorsal hipokampusda azalmadı. Fluoksetin apoptotik değişimleri geri çevirmesine rağmen propranolol çevirmedi ve proapoptotik proteinde artışa sebep oldu. Sonuç: Bu sonuçlarla fluoksetinin nöroprotektif rolü önerilebilir fakat propranolol için önerilemez.

Anksiyete araştırmalarında kullanılan sıçan davranış modelleri

Klinik oncesi calismalar kapsaminda olusturulan hayvan modelleri ile yeni ilaclarin anksiyolitik etkileri arastirilmaktadir. Bu modellerde en sik kullanilan hayvanlar sicanlar ve farelerdir. Anksiyete olusturulan hayvanlarda; cevreyi arastirma ve tanima davranislarindaki degisiklikleri inceleyerek, ilaca verilen yanita bu davranislardaki degisimlerin saptanmasi arastirmalarin temelini olusturmaktadir. Insanlarda gorulen anksiyete davranislarini tam olarak karsilamamakla birlikte hayvan modellerinde sicanlardaki bu davranislar modelin esasini olusturmaktadir. Stres yaratan etken olarak; elektrik soku, kafeslere egim verilmesi, olfaktor bulbektomi, ortamin yukseltilmesi, aydinlatmanin degistirilmesi, sosyal izolasyon, sualti travmalari, saldirgan hayvanin kendisine ya da saldirgan hayvana ait ipuclarina (saldirgana ait koku, tuy, idrar vb) maruz birakma kullanilmaktadir. Olusturulan strese karsi bu calismalarda genellikle asiri irkilme, bilissel bozukluklar, gelismis korku, dusuk sosyal etkilesim gibi anksiyete davranislarindaki degisimler olculmektedir. Sik kullanilan modeller arasinda; acik alan, zorunlu yuzme, catisma testleri, tekrarlayan stres uygulamalari, kuyruktan asma, yukseltilmis labirentler, sosyal izolasyon, uzun sureli tek bir strese maruz birakma, kronik hafif stres ve saldirgan ya da saldirgan ile ilgili ipuclarina maruz birakma testlerini saymak mumkundur.Bu derlemede, farkli stresorler ile anksiyete olusturmada kullanilan sican modelleri tanimlanmaktadir. Modellerin ozellikleri ve kullanim alanlari gozden gecirildiginde; kolay olusturulabilir ve tekrarlanabilir oluslari, yeni gelistirilmekte olan ilaclarin ya da mevcut benzer ilaclarin anksiyeteyi onleme ve tedavi edici etkileri daha etkin olarak arastirilmaktadir.