The Mechanisms Of Hippocampal Neuronal Injury And Mitochondrial Stress After Thrombotic Cerebral Ischemia In Tree Shrews

OBJECTIVE: To explore the hippocampal neuronal injury and the mitochondrial stress after thrombotic cerebral ischemia or glutamate and calcium solution affusing hippocampus in Tree Shrews.We observe the resulting changes in distribution of cytochrome c protein, at the same time, we detect the content of caspase (cysteine-containing aspartate-specific protease)mRNA. Our research explores how the ischemic microenvironment results in mitochondrial stress, proapoptotic protein release and activation of the caspase cascade. We provide a new molecular mechanism of mitochondrial stress in hippocampal neurons under an abnormal microenvironment.METHODS: Cerebral ischemic was induced by photochemical reaction and the right lateral hippocampus was microperfused by a kind of single-pumped push-pull perfusion system under three-dimensional orientation instrument in Tree Shrews. The expression of cytochrome c was observed in ischemic and perfused lateral hippocampi at different times by immunochemistry. Also, the hippocampus was removed, then mitochondria and cytoplasmic fragment were divided by low temperature centrifugation and the distribution of cytochrome c was assessed through western blot. We used real time fluorescence polymerase chain reaction to evaluate the relative amounts of caspase-3 and caspase-9 mRNA. In the treated group, we intravenously injected cyclosporine A (40mgkg-1) or ginkgolide B (Smg·kg^-1) at 6h after perfusing the glutamate-calcium chloride solutions into the hippocampus and inspected the above-mentioned items.RESULTS: Cytochrome c immunoreactivity was present in the cytosol of neurons at 4h after thrombosis, increased at 24h and decreased at 72h. Compared with sham group (Just iv rose bengal, not illumination), Western blot results demonstrated mitochondrial levels of Cyto C lessened at 4h after thrombosis (optical density,OD:...