肢体远端缺血预处理对抑制缺血性脑卒中的MRDWI研究

MRDWI research of the inhibition of limb remote ischemic preconditioning(LRP) on stroke

目的探讨经肢体远端缺血预处理(limb remote ischemic preconditioning,LRP)后大鼠脑缺血模型在DWI图像上的改变。方法 48只成年SD大鼠随机分为两组:LRP组,大鼠在行脑缺血诱导前经3个循环的右侧股动脉夹闭(15min)-恢复再灌(15min)的缺血预处理;脑缺血对照组,暴露右侧股动脉90min后线栓法栓塞右侧大脑中动脉1h,恢复再灌。分别在恢复再灌后1、3、12、24h行MRI检查采集T2WI/DWI图像;并结合神经学评分、TTC染色从行为学和形态学上进行辅助评价。结果 LRP组行为学评分为2.333±0.5164(n=20),较脑缺血组(1.333±0.5164,n=20)明显增加(P<0.01);LRP组大脑梗死面积为35.67±5.06%(n=5),脑缺血组的梗死面积为45.75±3.70%(n=5),经过预处理后脑缺血所致的梗死面积显著减少(P<0.01),与MRI检测结果一致。此外,连续性的DWI检测显示脑缺血组的病灶出现在恢复再灌后1h,而LRP组多出现在3h以后。结论单侧的LRP能够改善缺血所致的行为学缺陷,减轻脑缺血引起的脑水肿,并且还能够延迟病灶的出现,意味着LRP能够延长脑卒中的"治疗时间窗"。

Objective To investigate the changes of diffusion-weighted imaging（DWI） in rats underwent limb remote ischemic preconditioning（LRP） compared with those simply subjected to transient focal ischemia-reperfution.Methods Adult SD male rats were subjected to either remote preconditioning（RPC） or sham surgery and then subsequently underwent 1h right middle cerebral artery occlusion（MCAO）.Animals underwent MR T2/DWI imaging 1,3,12,24h after stroke and then neurological behavior evaluation and TTC staining were carried out.Results Limb-preconditioning with 3 cycles of 15 minutes performed immediately before stroke improved the neurologic deficit score from 2.333±0.5164（n=20） of control ischemia to 1.333±0.5164（n=20）.Infarct size was reduced from 45.75±3.70%（n=5） of control ischemia to 35.67±5.06%（n=5） through TTC staining,that was consistent with the result of MRI detection.Results of successional DWI detection showed that the present of lesion was prolonged by limb-preconditioning from 1h after stroke in control ischemia to 3h.Conclusion These results suggest that LRP performed in one limb improved neurological function,what＇s more,it not only alleviates but also prolongs the encephaledema leaded by ischemia,meaning LRP could lengthen the ＂therapeutic time windows＂ after stroke onset.