Effects of ischemic postconditioning on hippocampus rCBF and AS activation coupling response and possible mechanisms after thrombotic cerebral ischemia in tree shrews

• 1、Department of Pathophysiology, Kunming Medical College

Abstract：AIM: To study the coupling response of the regional cerebral blood flow (rCBF) and astrocyte (AS) activation coupling response in hippocampus CA1 area and to explore the possible mechanism and the effects of ischemic prostconditioning on rCBF and glial fibrillary acidic protein (GFAP) expression during focal cerebral thrombosis. METHODS: The thrombotic focal cerebral ischemia was induced by photochemical reaction in tree shrews, and ischemic postconditioning was established by cliped ipsilateral carotid of the animal at 4 hours after cerebral ischemia. The rCBF and GFAP expression in hippocampus CA1 area were detected, respectively, by laser-Doppler(LD) fowmeter and immunohistochemistry. RESULTS: The number of GFAP positive cells were increased markedly and GFAP expression enhanced(P＜0.01), AS oncosis were apparent 24 hours after cerebral ischemia. Postconditioning may increase hippocampus rCBF from 2.55±0.28 PU to 10.42±3.75 PU (P＜0.05) at 24 hours and from 9.84±1.22 PU to 18.74±1.6 PU ( P＜0.05) at 72 hours after the cerebral ischemia, and AS oncosis were inhibited markedly. CONCLUSION: The degrees rCBF reduction and AS activation in hippocampus CA1 shown a coupling response after focal cerebral thrombosis. Multiple, short, regional carotid occlusions may prolong “time window” of therapeutic cerebral ischemia, and the protection mechanism of ischemic prostconditioning may associated with the increase of rCBF, appropriate activation of AS and improvement of hippocampus microenvironment.

Keywords： Photochemistry Cerebral ischemia Prostconditioning Regional cerebral blood flow Astrocyte activation Coupling response Oncosis Tree shrew