Protective mechanism(s) of anti-oxidants in pancreatic-islet beta-cells against glucose toxicity and oxidative stress

Poon, Chui Wa Christina."August 2011."Thesis (M.Phil.)--Chinese University of Hong Kong, 2011.Includes bibliographical references (leaves 123-131).Abstracts in English and Chinese.ABSTRACT --- p.i論文摘要 --- p.viACKNOWLEDGEMENTS --- p.ixPUBLICATIONS --- p.xAbstracts --- p.xABBREVIATIONS --- p.xiiChapter 1. --- GENERAL INTRODUCTION --- p.1Chapter 1.1. --- Diabetes --- p.1Chapter 1.1.1. --- Overview --- p.1Chapter 1.1.2. --- Diagnostic Criteria of Type-2 Diabetes --- p.2Chapter 1.1.3. --- Type-2 Diabetes (T2DM) --- p.3Chapter 1.1.3.1. --- Impaired Insulin Synthesis and Insulin Secretory Defects in Type-2 Diabetes --- p.3Chapter 1.1.3.2. --- β-Cell Dysfunction --- p.5Chapter 1.1.3.3. --- Insulin Resistance --- p.5Chapter 1.1.4. --- Glucose Toxicity --- p.6Chapter 1.1.4.1. --- Fasting Hyperglycemia --- p.8Chapter 1.1.4.2. --- Postprandial Hyperglycemia --- p.8Chapter 1.2. --- Oxidative Stress --- p.8Chapter 1.2.1. --- ROS and Mitochondria --- p.8Chapter 1.2.2. --- ROS Production by Mitochondria --- p.9Chapter 1.2.3. --- The Relationship of Glucose Recognition by β-cells and Oxidative Stress --- p.11Chapter 1.2.4. --- Important Roles of Glutathione in Pancreatic β-cells and Glutathione Synthesis --- p.14Chapter 1.2.5. --- N-acetyl-L-cysteine - A Potential Drug Treatment for Type-2 Diabetes? --- p.17Chapter 1.3. --- Role of F-actin Cytoskeleton on Glucose-induced Insulin Secretion --- p.18Chapter 1.4. --- Current Clinical Treatments for Type-2 Diabetes Mellitus --- p.21Chapter 1.4.1. --- Metformin --- p.22Chapter 1.4.2. --- Sulfonylureas --- p.22Chapter 1.4.3. --- Thiazolidinediones --- p.23Chapter 1.4.4. --- Glinides (Meglitinide Analogues) --- p.23Chapter 1.4.5. --- α-Glucosidase (AG) Inhibitors --- p.24Chapter 1.4.6. --- Dipeptidyl Peptidase-4 (DPP-4) Inhibitors --- p.24Chapter 1.4.7. --- (Clinical) Antioxidant Treatment --- p.24Chapter 1.5. --- Animal Models Used in Type-2 Diabetes Research --- p.25Chapter 1.6. --- Aims of Study --- p.27Chapter 2. --- RESEARCH DESIGN & METHODS --- p.28Chapter 2.1. --- Materials --- p.28Table 1. Sources and concentrations of drugs tested in this study: --- p.28Culture Medium - --- p.29General Reagents --- p.29Chapter 2.2. --- Isolation of Islets of Langerhans and Single Pancreatic β-Cells --- p.31Chapter 2.3. --- Measurement of Mitochondrial ROS Levels --- p.32Chapter 2.4. --- Measurement of Islets Insulin Release and Insulin Content --- p.34Chapter 2.4.1. --- Preparation of Samples --- p.34Chapter 2.4.2. --- Enzyme-Link Immunosorbent Assay (ELISA) --- p.35Chapter 2.5. --- Immunocytochemistry --- p.35Chapter 2.6. --- Data and Statistical Analysis --- p.37Chapter 3. --- RESULTS --- p.38Chapter 3.1. --- "Effects of L-NAC, Various Oxidative Stress Inducers/Reducers and Actin Polymerisation/Depolymerisation Inducers on Releasable Insulin Levels and Insulin Contents in Response to Low Glucose (5 mM) and High Glucose (15 mM) of Isolated Pancreatic Islets of (db+/m+) and (db+/db+) Mice" --- p.38Chapter 3.1.1. --- Effect of L-NAC on Insulin Secretion and Insulin Contents --- p.38Chapter 3.1.2. --- Effect of Cytochalasin B on Insulin Secretion and Insulin Contents --- p.39Chapter 3.1.3. --- Effect of 4-Phenyl Butyric Acid on Insulin Secretion and Insulin Contents --- p.43Chapter 3.1.4. --- Effect of Ursodeoxycholic Acid on Insulin Secretion and Insulin Contents --- p.46Chapter 3.1.5. --- Effect of Hydrogen Peroxide on Insulin Secretion and Insulin Contents --- p.49Chapter 3.1.6. --- Effect of Jasplakinolide on Insulin Secretion and Insulin Contents --- p.53Chapter 3.1.7. --- Effect of Thapsigargin on Insulin Secretion and Insulin Contents --- p.57Chapter 3.1.8. --- Effect of BSO on Insulin Secretion and Insulin Contents --- p.61Chapter 3.2. --- "Effects of L-NAC, Various Oxidative Stress Inducers/Reducers and Actin Polymerisation/Depolymerisation Inducers on Mitochondrial ROS Levels in Response to High Glucose (15 mM) Challenge in Isolated Single Pancreatic β-Cells of (db +/m+) and (db +/db +) Mice" --- p.65Chapter 3.2.1. --- "Effects of L-NAC (20 mM), 4-Phenyl Butyric Acid (4-PBA) (1 mM), Ursodeoxycholic Acid (UA) (500 μg/ml), H202 (200 μM), Thapsigargin (0.5 μM) and DL-Buthionine-[S,R]-Sulfoximine (BSO) (0.1 μM) Pre-treatments on Mitochondrial ROS Level in Response to High Glucose (15 mM) Challenge" --- p.65Chapter 3.2.2. --- "Effects of L-NAC (20 mM), Cytochalasin B (10 μM) and Jasplakinolide (5 μM) Pre-treatments on Mitochondrial ROS Level in Response to High Glucose (15 mM) Challenge_" --- p.76Chapter 3.3. --- "Effects of L-NAC, Various Oxidative Stress Inducers/Reducers and Actin Polymerisation/Depolymerisation Inducers on F-actin Cytoskeleton Levels Incubated in Low Glucose (5 mM) and High Glucose (15 mM) Medium in Single Pancreatic β-Cells of Non-Diabetic (db +/m+) and Diabetic (db +/db +) Mice" --- p.81Chapter 4. --- DISCUSSION --- p.100Chapter 4.1. --- General Discussion --- p.100Chapter 5. --- SUMMARY --- p.120Chapter 6. --- FUTURE PERSPECTIVES --- p.121Chapter 7. --- REFERENCES --- p.12