肢体缺血预处理减轻大鼠海马缺血/再灌注损伤

目的:探讨肢体缺血预处理(LIP)对大鼠全脑缺血/再灌注损伤的影响.方法: 36只大鼠椎动脉凝闭后随机分为假手术(Control)组、脑缺血组、肢体缺血组、LIP 0 d组(LIP后即刻行脑缺血)、LIP 1 d组(LIP后1 d行脑缺血)和LIP 2 d组(LIP后2 d行脑缺血).重复夹闭大鼠双侧股动脉3次(每次10 min,间隔10 min)作为LIP,夹闭颈总动脉进行全脑缺血8 min后再灌注.硫堇染色观察海马CA1区组织学分级及锥体神经元密度以判断海马损伤程度.结果:脑缺血组海马CA1区锥体神经元损伤严重,与Control组比较,组织学分级明显升高,神经元密度明显降低(P<0.01).LIP 0 d组海马CA1区神经元损伤较脑缺血组明显减轻,组织学分级明显降低,神经元密度明显升高(P<0.01).而LIP 1 d组和LIP 2 d组大鼠海马CA1区锥体细胞缺失较多,仍有明显的组织损伤.结论:LIP可减轻随后立即发生的脑缺血/再灌注损伤,但对间隔1 d后的脑缺血/再灌注损伤无显著对抗作用.

Limb ischemic preconditioning decreases hippocampal ischemia/reperfusion injuries in rats

Aim: To explore the effects of limb ischemic preconditioning (LIP) on cerebral ischemia/reperfusion injuries. Methods: Thirty six wistar rats,of which bilateral vertebral arteries were occluded permanently,were randomly divided into the following 6 groups: control group,cerebral ischemic group,limb ischemic group,LIP 0 d group(cerebral ischemia was given immediately after LIP) ,LIP 1 d group(cerebral ischemia was given 1 d after LIP) and LIP 2 d group (cerebral ischemia was given 2 d after LIP). Global cerebral ischemia was performed by four vessels occlusion in rats. LIP was performed by occluding the bilateral femoral arteries for 10 min 3 times in a interval of 10 min. The histological grade and pyramidal neuronal density in the CA1 hippocampus were measured to quantitate the degree of hippocampal injury under thionin staining. Results: The histological grade was increased and the pyramidal neuronal density was decreased in the CA1 hippocampus of the cerebral ischemic group(P<0.01). The damage of the CA1 hippocampus in LIP 0 d group was significantly diminished,which represented by decreased histological grade and increased neuronal density compared with the cerebral ischemic group(P<0.01). But the CA1 hippocampus still showed obvious injuries in the LIP 1 d and LIP 2 d group. Conclusion: LIP performed immediately prior to cerebral ischemia could confer obvious protective effects on CA1 hippocampus against cerebral ischemia/reperfusion injuries. But LIP performed 1 d and 2 d prior to cerebral ischemia could not afford the protection against injuries induced by cerebral ischemia/reperfusion.