血红素加氧酶-1在肢体缺血后处理对脑缺血再灌注损伤的保护作用

Protection of heme oxygenase-1 in limb ischemic postconditioning on cerebral ischemia reperfusion injury

目的探讨血红素加氧酶-1(HO-1)在肢体缺血后处理(LPostC)对脑缺血再灌注损伤的保护作用及机制。方法 80只雄性SD大鼠随机分为假手术组(sham组)、缺血再灌注组(I/R组)、肢体缺血后处理组(LPostC组)和血红素加氧酶抑制剂锌原卟啉组(ZnPP组),每组20只。采用石蜡线栓法建立大脑中动脉缺血再灌注模型。夹闭双侧股动脉5 min,松开5 min,反复循环3次,制备LPostC模型。再灌注24 h后,采用2,3,5-氯化三苯基四氮唑(TTC)法测脑梗死体积;末端脱氧核苷酸转移酶介导的dUTP缺口末端标记测定(TUNEL)法检测神经细胞凋亡;用免疫组化和Western blotting方法测定HO-1的表达;分光光度计法测脑组织中丙二醛(MDA)和超氧化物歧化酶(SOD)的水平。结果与sham组相比,I/R组HO-1表达减少,SOD活性降低,MDA含量增加(均P<0.05)。与I/R组相比,LpostC组脑梗死体积缩小,神经细胞凋亡数量显著减少,HO-1表达明显增加,SOD活性升高且MDA含量降低(均P<0.05)。与LPostC组相比,ZnPP组脑梗死体积扩大,神经细胞凋亡数量增多,HO-1表达明显减少,SOD活性降低,MDA含量升高(均P<0.05)。结论 LPostC对脑缺血再灌注损伤具有保护作用,其作用机制可能与HO-1的表达增加有关。

Objective To investigate the protection of heme oxygenase-1(HO-1)in limb ischemic postconditioning(LPostC)on cerebral ischemia reperfusion injury.Methods Eighty male SD rats were randomly divided into sham-operation group(sham group),ischemia reperfusion group(I/R group),limb ischemia postconditioning group(LPostC group)and inhibitor of HO-1 group(ZnPP group),20 rats in each group.The ischemia and reperfusion injury model was established by line embolism with paraffin to block the middle cerebral artery.It includes three cycles of 5 min to occlusion and 5 min to loosen the bilateral femoral artery to make the LPostC model.After 24 h reperfusion,adopted 2,3,5-Triphenyltetrazolium chloride(TTC)staining to measure cerebral infarction volume.TdT-mediated dUTP Nick-End Labeling(TUNEL)staining was used to detected neuronal apoptosis.Immunohistochemistry and Western blotting method were employed to detect the expression of HO-1.Malondialdehyde(MDA)content and Superoxide Dismutase(SOD)activity in brain tissue were measured by spectrophotometer.Results The expression of HO-1 and SOD activity were lower whereas MDA content was higher in I/R group than in sham group(all P<0.05).When compared with those in I/R group,the cerebral infarction volume diminished,and the number of nerve cell apoptosis significantly reduced,and the expression of HO-1 sharply increased,meanwhile SOD activity rose and MDA content decreased in LPostC group(all P<0.05).Cerebral infarction volume,nerve cell apoptosis and MDA content stronger,whereas the expression of HO-1 and SOD activity markedly lower in ZnPP group than in LPostC group(all P<0.05).Conclusion Limb ischemia postconditioning plays the role to protect cerebral ischemia reperfusion injury,and the mechanism may be related to the upregulation of HO-1.