by Mo Flora. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1991. / Includes bibliographical references (leaves 168-184). / ACKNOWLEDGEMENT --- p.i / ABSTRACT --- p.ii / TABLE OF CONTENTS --- p.iv / Chapter CHAPTER ONE --- INTRODUCTION / Chapter 1.1 --- Stroke as a major disabling disease --- p.1 / Chapter 1.2 --- Classification of stroke --- p.4 / Chapter 1.3 --- Risk factors attributing to stroke --- p.15 / Chapter 1.4 --- Experimental methods to induce cerebral ischemia --- p.19 / Chapter 1.4.1 --- The establishment of animal models for stroke --- p.21 / Chapter 1.4.2 --- Gerbil as a putative model --- p.25 / Chapter 1.5 --- Mechanisms of focal ischemia damage --- p.30 / Chapter 1.6 --- Potential biochemical markers for cerebral ischemia --- p.38 / Chapter 1.7 --- Aim of investigation --- p.48 / Chapter CHAPTER TWO --- MATERIALS AND METHODS / Chapter 2.1 --- Common chemicals --- p.49 / Chapter 2.2 --- Common bench solutions --- p.52 / Chapter 2.3 --- Animals / Chapter 2.3.1 --- Gerbils --- p.52 / Chapter 2.3.2 --- Rabbit --- p.53 / Chapter 2.4 --- Establishment of an animal model / Chapter 2.4.1 --- Surgical methods for common carotid artery (CCA) ligation --- p.54 / Chapter 2.5 --- Methods to determine stroke conditions of gerbils / Chapter 2.5.1 --- Ocular fundus examination --- p.56 / Chapter 2.5.2 --- Stroke index --- p.56 / Chapter 2.5.3 --- Inclined plane method --- p.59 / Chapter 2.6 --- Preparation of gerbil brain for subsequent analysis / Chapter 2.6.1 --- Preparation of gerbil brain slices --- p.61 / Chapter 2.6.2 --- "2,3,5-triphenytetrazolium chloride (TTC) for quantitative staining of brain slices" --- p.61 / Chapter 2.6.3 --- Preparation of normal and stroke gerbil brain extract --- p.62 / Chapter 2.7 --- Polyacrylamide gel electrophoresis (PAGE) using a discontinuous buffer system / Chapter 2.7.1 --- Stock reagents --- p.63 / Chapter 2.7.2 --- Separation gel preparation --- p.65 / Chapter 2.7.3 --- Stacking gel preparation --- p.66 / Chapter 2.7.4 --- Electrophoresis conditions --- p.67 / Chapter 2.7.5 --- Staining and destaining --- p.67 / Chapter 2.8 --- Two dimensional slab gel electrophoresis / Chapter 2.8.1 --- Equipment --- p.70 / Chapter 2.8.2 --- Chemical --- p.70 / Chapter 2.8.3 --- Procedure --- p.74 / Chapter 2.9 --- Production of rabbit polyclonal antibodies against isolated stroke protein / Chapter 2.9.1 --- Isolation of stroke protein band from SDS-PAGE slab gel --- p.78 / Chapter 2.9.2 --- Production of anti-stroke protein serum in rabbits --- p.79 / Chapter 2.10 --- Western blotting method / Chapter 2.10.1 --- Reagents --- p.80 / Chapter 2.10.2 --- Procedures --- p.81 / Chapter 2.11 --- Extraction of total cellular RNA by lithium chloride method / Chapter 2.11.1 --- Reagents --- p.83 / Chapter 2.11.2 --- Procedures --- p.84 / Chapter 2.11.3 --- Checking the purity of the extracted RNA --- p.85 / Chapter 2.12 --- Purification of mRNA / Chapter 2.12.1 --- Reagents --- p.85 / Chapter 2.12.2 --- Procedure --- p.86 / Chapter 2.13 --- Verification of purity of mRNA / Chapter 2.13.1 --- Reagents --- p.87 / Chapter 2.13.2 --- Procedure --- p.88 / Chapter 2.14 --- Translation of gerbil brain mRNA in reticulocyte lysates and analysis of its product by SDS PAGE / Chapter 2.14.1 --- Reagents --- p.89 / Chapter 2.14.2 --- Procedures --- p.89 / Chapter CHAPTER THREE --- ESTABLISHMENT OF AN ANIMAL STROKE MODEL / Chapter 3.1 --- Foreword --- p.92 / Chapter 3.2 --- Preliminary studies / Chapter 3.2.1 --- Introduction --- p.92 / Chapter 3.2.2 --- Results --- p.93 / Chapter 3.2.3 --- Discussion --- p.96 / Chapter 3.3 --- Survival rate analysis / Chapter 3.3.1 --- Introduction --- p.97 / Chapter 3.3.2 --- Result --- p.98 / Chapter 3.3.3 --- Discussion --- p.102 / Chapter 3.4 --- Neurologic signs of ischemia / Chapter 3.4.1 --- Introduction --- p.103 / Chapter 3.4.2 --- Result --- p.105 / Chapter 3.4.3 --- Discussion --- p.111 / Chapter 3.5 --- Ocular fundus examination / Chapter 3.5.1 --- Introduction --- p.112 / Chapter 3.5.2 --- Result --- p.114 / Chapter 3.5.3 --- Discussion --- p.116 / Chapter 3.6 --- Inclined plane method / Chapter 3.6.1 --- Introduction --- p.117 / Chapter 3.6.2 --- Result --- p.118 / Chapter 3.6.3 --- Discussion --- p.121 / Chapter 3.7 --- Histologic examination using TTC as staining agent / Chapter 3.7.1 --- Introduction --- p.122 / Chapter 3.7.2 --- Result --- p.124 / Chapter 3.7.3 --- Discussion --- p.129 / Chapter CHAPTER FOUR --- IDENTIFICATION OF ALTERED PROTEIN PATTERN IN THE - BRAINS OF STROKE GERBILS BY ELECTROPHORETIC METHODS / Chapter 4.1 --- Separation of soluble brain extracts by SDS-PAGE analysis / Chapter 4.1.1 --- Introduction --- p.130 / Chapter 4.1.2 --- Result --- p.132 / Chapter 4.1.3 --- Discussion --- p.140 / Chapter 4.2 --- Two dimensional electrophoretic analysis of soluble brain extracts from stroke gerbils / Chapter 4.2.1 --- Introduction --- p.142 / Chapter 4.2.2 --- Result --- p.143 / Chapter 4.2.3 --- Discussion --- p.148 / Chapter CHAPTER FIVE --- ISOLATION OF STROKE-ASSOCIATED PROTEIN FROM BRAINS OF STROKE GERBILS BY IMMUNOCHEMICAL METHOD / Chapter 5.1 --- Introduction --- p.149 / Chapter 5.2 --- Result --- p.151 / Chapter 5.3 --- Discussion --- p.153 / Chapter CHAPTER SIX --- DETECTION OF NEW PROTEIN TRANSLATED FROM MESSENGER RIBONUCLEIC ACID FROM BRAINS OF STROKE GERBIL / Chapter 6.1 --- Introduction / Chapter 6.1.1 --- Extraction of stroke gerbil brain messenger ribonucleic acid --- p.154 / Chapter 6.1.2 --- Translation of mRNA --- p.154 / Chapter 6.2 --- Results / Chapter 6.2.1 --- Yield of total cellular RNA --- p.157 / Chapter 6.2.2 --- Verification of purity of mRNA --- p.157 / Chapter 6.2.3 --- Autoradiographic patterns of translated proteins --- p.159 / Chapter 6.3 --- Discussion --- p.163 / Chapter CHAPTER SEVEN --- GENERAL DISCUSSION --- p.165 / BIBLIOGRAPHY --- p.168

Cerebral ischemia is the principal cause of morbidity and mortality worldwide. In addition to neuronal loss associated with hypoxic-ischemic damage, cerebral ischemia is characterized by a neuromicrovascular injury. Nitrative stress and lipid peroxidation increase in hypoxic-ischemic damages and play an essential role in neuromicrovascular injury leading to cerebral ischemia. We hypothesized that newly described lipid peroxidation products, termed trans-arachidonic acids (TAA), could be implicated in the pathogenesis of hypoxia-ischemia by affecting the cerebral vasomotricity and microvascular integrity. / The effects of TAA on neuromicrovascular tone were tested ex vivo by monitoring the changes in vascular diameter of rat cerebral pial microvessels. Four isomers of TAA, namely 5 E-AA, 8E-AA, IIE-AA and 14 E-AA induced an endothelium-dependent vasorelaxation. Possible mechanisms involved in TAA-induced vasorelaxation were thoroughly investigated. Collectively, data enclosed revealed that TAA induce cerebral vasorelaxation through the interactive activation of BKCa channels with heme oxygenase-2. This interaction leads to generation of carbon monoxide which in turn activates soluble guanylate cyclase and triggers vasorelaxation. / Chronic effects of TAA on microvascular integrity were examined by generating a unilateral hypoxic-ischemic (HI) model of cerebral ischemia on newborn rat pups. Our HI model showed microvascular degeneration as early as 24h post-HI, preceded by an increase in cerebral TAA levels. HI-induced microvascular lesions were dependent on nitric oxide synthase activation and ensued TAA formation. Although the molecular mechanisms leading to TAA-induced microvascular degeneration were, in part uncovered for the retina, the primary site of action of TAA remains unknown. We demonstrated that TAA binds and activates GPR40 receptor, a newly described free fatty acid receptor. Importantly, GPR40 receptor knock-out prevents TAA-induced reduction in cerebral microvascular density and limits HI-induced brain infarct.

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