| Introduction: Cerebral ischemia-reperfusion induced injury is a major contributor affecting therapy of cerebral ischemia patients. There are no specific treatment in the clinical practice at present. Apoptosis which is one of the main patterns of neuronal death plays an important role in cerebral ischemia-reperfusion induced injury. So anti-apoptosis treatment may become one of important remedies for cerebral ischemia-reperfusion induced injury. Sevoflurane is a new volatile anaesthetic. Recently, it is found that sevoflurane can attenuate cerebral ischemia-reperfusion induced injury by the mechanism like ischemia preconditioning or KATp channel opener. We used it preconditioning rats and studied the effects of sevoflurane against focal ischemia-reperfusion induced injury. The possible mechanism of anti-apoptosis was studied too.Methods: Part one: Twelve Sprague-Dawlay (SD) rats were randomly divided into two groups: ischemia-reperfusion group(IR) and sevoflurane preconditioning group(S). We established right middle cerebral artery occlusion (MCAO) model based on lea Longa method. Briefly, rats were anesthetized with intraperitoneal injection of chloral hydrate, the right common carotid artery(CCA), internal carotid artery(ICA) and external carotid artery(ECA) were exposed through a midline incision of the neck. A 3-0 silica gel-coated nylon suture was used asan occluder and was inserted via the CCA. The ECA and the CCA were ligated. The occluder advanced into the ICA about 17. 5-18. 5mm beyond the carotid bifurcation. At 90min after MCAO, reperfusion began with the suture withdrawn. S group received 1h sevoflurane preconditioning (2.4%) before MCAO. After 24h reperfusion, the neurological scores were determined by the method described by Zea Longa. Then rats were decapitated, the brains were stained using triphenyltetrazolium chloride(TTC) to calculate infarct volume percentage.Part two: Eighteen SD rats were randomly divided into three groups: control group(C),ischemia-reperfusion group(IR) and sevoflurane preconditioning group(S). We established right middle cerebral artery occlusion (MCAO) model based on Zea Longa method. In C group, no suture was inserted, while, S group received lh sevoflurane preconditioning (2.4%) before MCAO. After 24h reperfusion, rats were decapitated. Apoptosis neurons in cortex were observed by transmission electron microscope and Hematoxylin and Eosin(HE). TUNEL(TdT mediated dUTP nick end label ing)method was used to count apoptosis neurons in cortex.Part three: Eighteen SD rats were randomly divided into three groups: control group(C), ischemia-reperfusion group(IR) and sevoflurane preconditioning group(S). We established right middle cerebral artery occlusion (MCAO) model based on Zea Longa method. In C group, no suture was inserted, while, S group received lh sevoflurane preconditioning (2.4%) before MCAO. After 24h reperfusion, rats were decapitated. Fresh ischemic brain tissue was taken out and Caspase~3 zymogen and 20000 segment was checked by Western-blot.Results:1. The neurological scores of sevoflurane preconditioning group were lower than that of ischemia-reperfusion group. The infarct volume percentage of IR group and S group was 22.9 + 2.21% and 15.2 ± 1.52%(P<0.05). Sevoflurane preconditioning can improve neurological outcome induced by ischemia-reperfusion.2. It was observed clearly by HE staining and light microscope and transmission electron microscope that there were many apoptosis neurons in the cortex in ischemia-reperfusion group. Apoptosis neurons in sevoflurane preconditioning group distribute sparsely. Apoptosis neurons densities(cell number/0. lmm2) by TUNEL staining: control group, 13.0+1.41;ischemia-reperfusion group, 189. 8 + 6. 79 (P<0. 05 VS C group);sevoflurane preconditioning group, 110.5 + 4. 32(P<0. 05 VS C group;P<0. 05 VS IR group). Sevoflurane preconditioning can inhibit neuron apoptosis induced by ischemia-reperfusion.3. The relative gray values of contents of procaspase-3 by Western-blot: control group, 16.72 +2.96;ischemia-reperfusion group, 76.14 +3.45(P<0.05 VS C group);sevoflurane preconditioning group, 51.15 +3.10(P<0. 05 VS C group;P<0.05 VS IR group) ? 20000 segment: control group, 8. 17 + 2. 31;ischemia-reperfusion group, 58.95 +6.28(P<0.05 VS C group);sevoflurane preconditioning group, 31.23 +5. 43(P<0. 05 VS C group;P<0. 05 VS IR group) ? Sevoflurane preconditioning maybe attenuate neuron apoptosis by inhibiting caspase-3 expression and activity.CONCLUSIONS1. Neuronal apoptosis plays an important role in cerebral ischemia-reperfusion induced injury.2. Sevoflurane preconditioning can provides neuroprotection by inhibiting neuron apoptosis induced by ischemia-reperfusion.3. Sevoflurane preconditioning maybe attenuate neuron apoptosis by inhibiting caspase-3 expression and activity. |
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