Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Blood-Brain Model Comprising Mouse Brain Tissue(Izmir Institute of Technology, 2023) Demi̇r, Ceylan; Okvur, Devri̇m PesenBeyin kan bariyeri (BBB), beyin hastalıklarının patolojilerinde ve ilaç dağıtımı gibi tedavi yaklaşımı çalışmalarında büyük önem taşımaktadır. Kan beyin bariyerinin yüksek verimli ve gerçekçi tasarımlara sahip mikroakışkanlarla modellenmesi, araştırmalarda hayvan kullanımının azaltılması, hassas tıbbın yaygınlaştırılması ve bilimsel araştırmaların ilerletilmesi için etkili bir seçenektir. Bu çalışmada yetişkin fare beyin dokusunu içerecek şekilde bir BBB modelinin geliştirilmesi amaçlandı. Bu amaçla yaklaşık olarak eşit büyüklükte ve besin alımına yetecek kadar küçük beyin dokusu elde edilmesini sağlayacak bir araç ve yöntem geliştirildi. BBB modeline uygun mikroakışkan model geliştirilmiş ve çalışmanın ilerlemesine göre özellikleri optimize edilmiştir. Doku canlılığına ilişkin parametreler optimize edildi ve doku, mikroakışkan içinde yaşadı. Farklı bileşenlerin dahil edilmesiyle doku içeren ve doku içermeyen ortamların mikrovasküler ağ oluşumları incelendi. BBB modelinin işlevsel durumu, optimize edilmiş vasküler ağ ve endotel hücre katmanının oluşturulmasından sonra geçirgenlik tahlili ile test edildi.Master Thesis Investigation of the Pathology of Brain Derived Endothelial Cells in In-Vitro Hypoxia Models(01. Izmir Institute of Technology, 2021) Erdemli, Kısmet Tuğçe; Tosun, ÇiğdemThe blood brain barrier (BBB) is a vital structure that protects brain homeostasis. Endothelial cells (EC) have a significant role in regulating the BBB structure and function. Several studies have revealed the association of SUR1-TRPM4 channels that regulate this secondary damage of CNS injuries. After the activation of the channel, Na+ influx causes depolarization, cell swelling (edema) and ultimately oncotic cell death. Hypoxia inducing factor (HIF) transcription factor that has been reported to activate more than 100 genes to adapt to a hypoxic condition. Once Hif1-⍺ is translocated into the nucleus, it can dimerize with HIF1-ß to produce HIF that is critical in hypoxic conditions and regulate cell cycle arrest or cell death pathways. Hypoxia can occur in an O2 dependent and independent manner. In this study, CoCl2 and hypoxia chamber which was cost-effective and reliable were optimized. Cellular death was calculated with Trypan blue staining in this novel hypoxia chamber model and compared with CoCl2 models. In addition, morphological changes were observed in microscopic analysis. Hif1-⍺, caspase-3 and NF-κB translocation to the nucleus localization were quantified. Cell viability was different between the CoCl2 model and novel hypoxia chamber model at 24 hours. The cellular death increased with CoCl2 exposure, where no change was noted in the hypoxia chamber model. Time dependent Hif1-⍺ upregulation was also demonstrated that peaked at 12-hours. Finally, NF-κB translocation into the nucleus was significantly increased at 24 hours of hypoxia exposure. The results reveal that the inflatable hypoxia chamber model could be reliably used to mimic hypoxia in an in-vitro setting. Hif1-⍺ activated in a time dependent manner, along with NF-κB. The upregulation of these transcription factors can ultimately affect the cellular death mechanisms differentlyMaster Thesis The Effect of Glibenclamide in Lipopolysaccharide Stimulated Brain Microvascular Endothelial Cells(Izmir Institute of Technology, 2019) Cihankaya, Hilal; Tosun, ÇiğdemEndothelial cells are essential components of the blood brain barrier (BBB) that regulate the exchange of solutes between the vasculature and the brain parenchyma. The integrity of the BBB is disrupted after central nervous system (CNS) injuries, and it has been associated with the Sur1-Trpm4 channels. Once these channels are opened, Na+ flows into the cells causing edema and cell death. To mimic CNS injuries in vitro, lipopolysaccharide (LPS) was used as an endotoxin to initiate proinflammatory mediators to increase endothelial permeability, and glibenclamide was used as an antagonist of Sur1-Trpm4 channels to reduce the inflammatory response and to maintain the structural integrity of BBB proteins. To demonstrate the role of glibenclamide following LPS stimulation, we determined the cytotoxicity of LPS in bEnd.3 cells by cleaved caspase-3 expression and propidium iodide staining. We also investigated the protective effect of glibenclamide on NF-B translocation, and BBB proteins; collagen IV (COL IV) and zonula occludens 1 (ZO-1) in LPS stimulated bEnd.3 cells. Our results revealed that 1g/ml LPS exposure was sufficient for NF-B nuclear translocation, along with a statistically significant decrease in the expressions of COL IV and ZO-1 proteins, and a significant increase in cell death. We also demonstrated that glibenclamide was able to restore the expressions of COL IV and ZO-1, significantly reduce NF-B translocation, and cell death. Taken together, LPS induction in bEnd.3 cells can be used to investigate endothelial cell dysfunction due to inflammation in stroke and trauma models and glibenclamide can be used as a protective drug to inhibit LPS stimulated inflammatory response, cell death and disruptions in the structures of key BBB proteins.