大鼠局灶性脑缺血再灌注后PAO活性和多胺含量变化及意义

目的：检测大鼠局灶性脑缺血再灌注不同时相脑皮质及皮质下多胺氧化酶(PAO)活性和多胺含量,探讨局灶性脑缺血再灌注后PAO活性和多胺含量变化的时相规律及意义。方法：采用改良的Longa线栓法，建立大鼠局灶性脑缺血2h后再灌注2，4，8，24h动物模型，用高香草酸辣根过氧化物酶荧光法测定脑缺血区皮质和皮质下不同时相PAO活性变化，用高效液相色谱法测定脑缺血区皮质和皮质下不同时相多胺的含量。结果：实验组大鼠脑缺血区皮质和皮质下PAO活性在再灌注8h后开始升高(P<0.01),其高峰出现在再灌注24h后(P<0.01)；实验组腐胺含量于再灌注4h后即开始逐渐升高(P<0.05)，高峰出现在再灌注24h后(P<0.05)；再灌注8，24h实验组精脒、精胺含量较对照组明显下降(P<0.05)。结论：脑缺血再灌注后PAO活性明显增高，PAO活性的增高促使腐胺高峰的形成，对脑缺血损伤有促进作用。

Changes and significance of PAO activities and polyamine levels at different time of reperfusion after transient focal cerebral ischemia in rats

Objective To assay the changes of polyamine oxidase (PAO) activities and polyamine levels in the cortex and subcortex at different time of reperfusion following 2 h focal cerebral ischemia in rats in order to explore the regularity and significance of these changes.Methods Rats of 2 h reversible focal cerebral ischemia were produced by ameliorated method of Longa's intraluminal suture occlusion of middle cerebral artery(MCA). PAO activities and polyamine levels in the cortex and subcortex were measured by homovanillic acid fluorometry and high-performance liquid chromatograph (HPLC) after 2,4,8, and 24 h reperfusion following 2 h ischemia, respectively.Results PAO activity of the experimental group increased after 8 h reperfusion (P<0.01). The peak value of PAO activity appeared after 24 h reperfusion (P<0.01). Putrescine level of the experimental group was elevated after 4 h reperfusion ((P<)0.05), and the peak value of putrescine appeared after 24 h reperfusion (P<0.05). Spermidine and spermine levels of 8,24 h reperfusion in the experiment group decreased significantly compared with the control group (P<0.05). Conclusion PAO activities increased significantly after reperfusion following transient focal cerebral ischemia, which promoted the later peak production of putrescine. It may be contributed to the brain damage after cerebral ischemia.