Browsing by Author "Tuerkez, Hasan"

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Assessment of the Neuroprotective Potential of D-Cycloserine and L-Serine in Aluminum Chloride-Induced Experimental Models of Alzheimer's Disease: In Vivo and In Vitro Studies
(Frontiers Media SA, 2022) Tozlu, OEzlem OEzdemir; Tuerkez, Hasan; Okkay, Ufuk; Ceylan, Onur; Bayram, Cemil; Hacimueftueoglu, Ahmet; Mardinoglu, Adil
Alzheimer's disease (AD) is a neurodegenerative disease characterized by the accumulation of amyloid-beta (A beta) plaques and neurofibrillary tangles in the brain accompanied by synaptic dysfunction and neurodegeneration. No effective treatment has been found to slow the progression of the disease. Therapeutic studies using experimental animal models have therefore become very important. Therefore, this study aimed to investigate the possible neuroprotective effect of D-cycloserine and L-serine against aluminum chloride (AlCl3)-induced AD in rats. Administration of AlCl3 for 28 days caused oxidative stress and neurodegeneration compared to the control group. In addition, we found that aluminum decreases alpha -secretase activity while increasing beta -secretase and gamma -secretase activities by molecular genetic analysis. D-cycloserine and L-serine application resulted in an improvement in neurodegeneration and oxidative damage caused by aluminum toxicity. It is believed that the results of this study will contribute to the synthesis of new compounds with improved potential against AlCl3-induced neurodegeneration, cognitive impairment, and drug development research.
Genotoxic Effect of Beryllium Chloride and Protective Role of Crataegus Oxyacantha L. (Hawthorn) Fruit Extract in Vitro
(Parlar Scientific Publications (p S P), 2012) Dirican, Ebubekir; Tuerkez, Hasan
Beryllium (Be) is used in various industries (electronics, energy, automotive, and aerospace applications); however, there is very scarce data on its genotoxicity. On the other hand, Crataegus oxyacantha is a thorny tree that thrives in hedgerows and fields in the temperate regions of Europe and the British Isles. Besides, C. oxyacantha berry extract is known as one of the most powerful antioxidants. In this study, antigenotoxic effects of C. oxyacantha against Be-induced chromosomal aberrations (CA), sister chromatid exchanges (SCE) and micronucleus (MN) formation in human lymphocytes were investigated. All cultures were treated with 120 mg/L beryllium chloride (BeCl2) for 48 h. Three different concentrations (25, 50 and 100 mg/L) of C. oxyacantha fruit extract was added to the BeCl2-treated cultures. In BeCl2 and C. oxyacantha combination, the frequency of abnormal cells and CA/cell significantly decreased compared to BeCl2 alone. Statistically significant reduction was also observed in SCE/cell and MN frequencies in all the treatments. These results illustrated anticlastogenic and antimutagenic effects of C. oxyacantha fruit extract against BeCl2-induced genetic damage. On the other hand, BeCl2 + C. oxyacantha treatments induced significant reduction in the mitotic index, with regard to BeCl2 treatment alone. Based on the results of this study, it may be concluded that dose-controlled C. oxyacantha diet may play a protective role in the process of BeCl2 mutagenesis and/or carcinogenesis.
In Vitro and In Vivo Neuroprotective Effects of Sarcosine
(Wiley, 2022) Tanas, Arzuguel; Tozlu, Ozlem Ozdemir; Gezmis, Tugba; Hacimueftueoglu, Ahmet; Abd El-Aty, A. M.; Ceylan, Onur; Tuerkez, Hasan
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by behavioral and psychological symptoms in addition to cognitive impairment and loss of memory. The exact pathogenesis and genetic background of AD are unclear and there remains no effective treatment option. Sarcosine, an n-methyl derivative of glycine, showed a promising therapeutic strategy for some cognitive disorders. To our knowledge, the impacts of sarcosine supplementation against AD have not yet been elucidated. Therefore, we aimed to determine the neuroprotective potential of sarcosine in in vitro and in vivo AD model. In vitro studies have demonstrated that sarcosine increased the percentage of viable cells against aluminum induced neurotoxicity. In AlCl3-induced rat model of AD, the level of antioxidant capacity was significantly decreased and expression levels of APP, BACE1, TNF-alpha, APH1A, and PSENEN genes were elevated compared to the control group. Additionally, histopathological examinations of the hippocampus of AlCl3-induced rat brains showed the presence of neurofibrillary tangles (NFTs). However, the administration of sarcosine produced marked improvement and protection of AD-associated pathologies induced by AlCl3 in experimental rats. Therefore, this investigation may contribute to design novel therapeutic strategies using sarcosine for the management of AD pathologies.