摘要目的 探索脑缺血/再灌注损伤(ischemia/reperfusion injury,I/RI)后甘露醇干预的最佳时机.方法 健康昆明小鼠36只,制备I/RI模型后,按随机数字表法分为6组(每组6只):假手术组(A组)、对照组即I/RI组(B组)和再灌注即刻、30 min、1、1.5 h甘露醇干预组(分别为C、D、E和F组).再灌注24 h后取脑组织,对各组海马CA1区细胞的病理形态学变化、存活细胞数和变性细胞率作出检测.结果 脑缺血/再灌注(ischemia/reperfusion,I/R)即刻甘露醇干预组锥体细胞大多保持正常形态,细胞结构完好,细胞间质无水肿表现；存活细胞数为(22.0±1.1)个/100 μm,与假手术组(23.0±0.9)个/100 μm比较差异无统计学意义(P＞0.05)；变性细胞率(8.17％)较对照组(40.17％)明显减少(P＜0.05),与假手术组(7.33％)比较差异无统计学意义(P＞0.05).再灌注30 min以上甘露醇再干预,神经元损伤不能改善.结论 脑I/R早期血压梯度建立后及时给予甘露醇建立反相的渗透压梯度,可以有效防止细胞水肿的形成,并能阻断由此引发的不可逆细胞损害.研究发现恢复灌注30 min以上再给予甘露醇基本无效.

abstractsObjective To investigate the optimal timing of mannitol intervention in cerebral ischemia-reperfusion injury.Methods Thirty-six mice were randomly divided into six groups (n=6):The sham operation group (group A),the control group (ischemia-reperfusion injury group,group B),aud the mannitol intervention group at the time of 0 min,30 min,1 h and 1.5 h after reperfusion (group C,D,E,F).Taken the brain twenty-four hours after ischemia-reperfusion injury.Morphological changes,viability and degradation of cells in the area of CA1 of hippocampus were studied in each group.Results In the experimental group with mannitol intervention immediately after reperfusion,most hippocampal pyramidal cells remained normal morphology with intact structures and no intercellular edema was observed.The amount of viable cells was (22.0±1.1) per 100 μm which was not significantly different from that of the sham operation group (23.0±0.9).The incidence of cell degradation was 8.17％,which was significantly lower than that of the control group (40.17％,P＜0.05).The cell degradation difference between the experimental group and sham operation group(7.33％) was not significant(P＞0.05).Mannitol intervention beginning over 30 min after reperfusion failed to alleviate neuron injury.Conclusion After the establishment of blood pressure gradient,inverted osmotic pressure gradient by means of prompt mannitol intervention at the early stage of cerebral ischemia-reperfusion can effectively prevent the formation of intracellular edema and avoid the consequent irreversible cellular injury.Mannitol intervention beginning over 30 min after reperfusion was proved ineffective.