急性等容量血液稀释对大鼠全脑缺血再灌注时海马组织细胞凋亡的影响

Effect of acute normovolemic hemodilution on apoptosis in hippocampal cells induced by global cerebral ischemia-reperfusion in rats

目的探讨急性等容量血液稀释（ANH）对大鼠脑缺血再灌注时海马组织细胞凋亡的影响。方法健康清洁级雄性sD大鼠36只，体重280—320g，50～60d龄，采用随机数字表法，将其随机分为3组（n=12），假手术组（s组）仅游离暴露双侧椎动脉及颈总动脉；脑缺血再灌注组（I／R组）和ANH组采用四血管阻断法制备全脑缺血再灌注损伤模型。ANH组于灼烧双侧椎动脉后24h实施ANH，经股动脉放血（经10min），放血的同时股静脉输注6％羟乙基淀粉130／0．4氯化钠，ANH结束后10min时夹闭双侧颈总动脉5min。于再灌注24h时，处死大鼠，取脑组织，分离海马，采用流式细胞术测定细胞凋亡情况，采用反转录聚合酶链反应法测定Apaf-1mRNA及caspase-3mRNA的表达。结果与s组比较，I／R组和ANH组海马组织细胞凋亡率升高，海马组织Apaf-1mRNA及caspase-3mRNA表达上调（P〈0．01）；与I／R组比较，ANH组海马组织细胞凋亡率降低，海马组织Apaf-1mRNA及caspase-3mRNA表达下调（P〈0．01）。结论ANH可抑制大鼠全脑缺血再灌注时海马神经细胞凋亡，其机制与下调Apaf-1及caspase-3表达有关。

Objective To investigate the effect of acute normovolemic hemodilution （ANH） on the apoptosis in hippocampal cells induced by global cerebral ischemia-reperfusion （I/R） in rats. Methods Thirty-six healthy 50-60 day old male SD rats weighing 280-320 g were randomly divided into 3 groups （ n = 12 each） ： group sham operation （group S）; group global cerebral I/R （group I/R） and group ANH. Global cerebral I/R was pro- duced by 4-vessel technique described by Pulsinelli et al. in groups I/R and ANH. ANH was carried out at 24 h after cauterization of bilateral vertebral arteries, before occlusion of bilateral carotid arteries. Blood was withdrawn from femoral artery until Hct was reduced to 30% and equal volume of hydroxyethyl starch 130/0.4 sodium chloride was infused into femoral vein simultaneously, Bilateral carotid arteries were blocked for 5 min at 10 rain after ANH. The rats were sacrificed at 24 h of reperfusion and their hippoeampi were isolated. Apoptosis was detected by flow cytometry. The expression of Apaf-1 mRNA and caspase-3 mRNA was determined by RT-PCR. Results Global cerebral I/R significantly increased apoptosis index and up-regulated Apaf-1 mRNA and caspase-3 mRNA expression in group I/R as compared with group S. ANH significantly attenuated apoptosis and down-regulated Apaf-1 mRNA and caspase-3 mRNA expression in group ANH compared with group I/R. Conclusion ANH can reduce hippocampal cell apoptosis induced by cerebral I/R through down-regulation of Apaf-1 and caspase-3 expression in hippocampus.