血红素氧合酶-1、诱导型一氧化氮合成酶在局灶性脑缺血中的表达

目的观察两种不同信使分子CO／NO的限速酶血红素氧合酶-1（HO～1）、诱导型一氧化氮合成酶（iNOS）在局灶性脑缺血中的表达，初步探讨HO-1、iNOS在局灶性脑缺血中的不同作用。方法采用免疫荧光技术，观察HO-1、iNOS在局灶性缺血脑组织中不同时间点的表达及分布。结果iNOS在海马、皮质、基底节均有分布以灶周皮质最多。HO-1在同侧海马、皮质、基底节、丘脑均有分布，以灶周皮质为最多。iNOS的表达在缺血后2h出现，24～48h达最高峰，以后逐渐下降。HO-1表达在缺血后0．5h即出现，缺血后6～12h达最高峰。在缺血皮质半暗带的某些神经细胞有iNOS及HO-1的共同表达。结论脑缺血早期即有HO-1的表达，而iNOS表达则较晚出现，其表达的高峰期晚于HO-1。在半暗带的某些神经细胞可见有HO-1和iNOS的同时表达。

Expression of HO-1 and iNOS in Focal Cerebral Ischemia in Rats

Objective To study the different roles of heme oxygenase-1 (HO-1) and iNOS protein during permanent focal cerebral ischemia in rats.Methods By using immunofluorescence, the co-expression and distribution of HO-1 and iNOS protein in the brains of focal ischemia at different time points were investigated, and the changes in fluorescent intensity were observed.Results iNOS was expressed in hippocampus, cortex and basal nuclei, mostly in cortex around the ischemia area. The iNOS positive neural cells were observed in 2 h after ischemia, peaked at 24-48 h, then slowed down, lasted till 7th day after middle cerebral artery occlusion (MCAO). HO-1 was expressed in the collateral hippocampus, cortex, basal nuclei and thalamus, mostly in perifocal ischemic cortex. With time going on, the number of HO-1 immunofluorescence positive neural cells was increased, peaked at 6-12 h, then slowed down, lasted till 7 th day after MCAO. The number of HO-1 immunofluorescence positive neural cells was less than that of iNOS in the same area. There was about 5 %-10 % neural cells co-expressing HO-1 and iNOS.Conclusion In the early stage of cerebral ischemia, HO-1positive neural cells were observed. The increased iNOS expression was later than that of HO-1. The co-expression of HO-1 and iNOS was detectable in perifocal ischemic tissue.