缺血预适应对沙土鼠脑缺血再灌注后纹状体多巴胺及其代谢产物的影响

目的　研究缺血预适应对沙士鼠脑缺再灌注后纹状体中多巴胺(DA)及其代谢产物的影响,以探讨其神经保护作用的可能机制。方法　应用沙土鼠脑缺血再灌注模型,脑缺血时间为 5min。96只沙土鼠随机分为假手术组 (S)、缺血组(I)、单纯预适应组 (Po)、缺血预适应组 (Ip)。在再灌注 0(即缺血末)、5、30、60min时,断头、分离纹状体,用高效液相-电化学检测器 (HPLC ECD)分别测定各组沙土鼠纹状体DA、3, 4双羟苯乙酸 (DOPAC)和高香草酸 (HVA)的含量。结果　与假手术组相比,短暂缺血组在缺血再灌注期间纹状体中DA、DOPAC和HVA含量均无显著性变化 (P>0 05)。再灌注期间,预适应、缺血再灌注组DA含量均显著低于假手术组,但在再灌注 0min和 30min时,预适应组DA含量及显著高于缺血再灌注组,分别增加了 28% (P<0 01)和 22% (P<0 05)。与假手术组相比,预适应组的DOPAC和HVA含量在再灌注期间均无显著变化 (P>0 05 );缺血再灌注组DOPAC含量在再灌注 5min时有明显增加;HVA含量在再灌注 30min时增加至峰值。结论　缺血预适应能部分抑制沙土鼠脑缺血再灌注期间纹状体DA的降低,显著减少DA氧化代谢产物的产生,从而在脑缺血再灌注损伤中起保护作用。

The effect of ischemic preconditioning on striatal dopamine and its metabolites after cerebral ischemia-reperfusion in gerbils

Aim To investigate the effect of ischemic pr econditioning on striatal dopamine and its metabolites after cerebral ischemia a nd reperfusion in gerbils.Methods We measured the content of do pamine (DA),3,4-dihydroxyphenylacetic acid (DOPAC),and homovanillic acid(HVA ) by high pressure liquid chromatography (HPLC) with electrochemical detection ( ECD) at 0 (at the end of ischemia),5,30,and 60 min of reperfusion in striatal of the brain after occlusion of both common carotid arteries for 5 min in gerbi ls with and without ischemic preconditioning.Animals were divided into four grou ps——the sham operated (S)group, the ischemia(I)group with 5 min ischemia wit hout prior preconditioning, the preconditioning only (Po) group with 2-minute i schemia twice 2 days without 5-minute ischemia, and the ischemic preconditionin g (Ip) group with 2-minute ischemia twice 2 days before 5 min ischemia(n=24 for each group).Results There was no significant difference in striatal DA, DOPAC and HVA contents between Po group and S group during reperfu sion. Although the striatal DA contents in Ip and I group were lower than those in S group (P<0.05), they were significantly higher in Ip group than those in I group, increased by 28% (P<0.01) and 22% (P<0.05) at 0,30 min o f reperfusion, respectively. There was no significant difference in striatal con tent of DOPAC and HVA between Ip and S group (P>0.05). In the I group,str iatal content of DOPAC increased at 5 min of reperfusion;striatal content of HV A increased during reperfusion and reached to peak value at 30 min of reperfusio n.Conclusion Ischemic preconditioning can partially inhibit the decrease of striatal content of DA, and significantly attenuate the increase of DOPAC and HVA content after ischemia-reperfusion.