STRESS PROTEIN INDUCTION IN GERBIL BRAIN AFTER ISCHEMIA

从最初的归纳论证到现在的大 哺乳动物应激(热休克)蛋白，HSP70，在短暂后 缺血，努力已经指向a)量化 热休克蛋白70和其他应激诱导的转录增加 缺血后的mRNAs；b)免疫细胞化学定位 热休克蛋白70在沙土鼠脑中的诱导。HSP70和HSP70的诱导 泛素mRNA序列现在已经被证明是在 用cdna探针检测脑缺血。泛素信使核糖核酸只是适度的 诱导(增加70%)，再循环6小时达高峰。热休克蛋白70 M RNA的诱导作用更强(超过2倍)，并在 12小时，与HSP70最大翻译时间一致 先前确定的。一个引人注目的颞叶和解剖学 缺血后热休克蛋白70的诱导模式 使用被认为是特异性肿瘤的单抗 HSP70家族的诱导形式。对照动物显示 仅限于室管膜细胞衬里的免疫反应 脑室，这在缺血后保持不变。 在缺血10分钟后的24小时再循环中，HSP70 免疫反应阳性细胞见于齿状颗粒细胞、神经元。 缰核和纹状体，以及在一些基底前脑和 皮质区域。在48小时，CA3有明显的强烈反应。 海马神经元。到96小时，免疫反应性为 仅限于CA3的一些残留染色，并具有很强的标记 内嗅区和其他皮质区域。有趣的是， 在海马区和其他边缘可见阳性细胞。 结构、电路，这些可能是 提出了缺血后神经元丢失的兴奋毒性机制。 热休克蛋白70在CA3和齿状颗粒中有明显积聚 在短暂的缺血中存活，但被大大削弱的细胞 在CA1神经元中，不存在这种现象。热休克蛋白70的这种异质性 诱导可能反映了缺血后代谢应激的变化 以及不同细胞群体对应激的反应。

Since the initial demonstration of induction of the major mammalian stress (heat shock) protein, hsp70, after transient ischemia, efforts have been directed toward a) quantitating increased transcription of hsp70 and other stress-inducible mRNAs after ischemia, and b) immunocytochemical localization of hsp70 induction in gerbil brain. Induction of both hsp70 and ubiquitin mRNA sequences have now been demonstrated after ischemia using cDNA probes. Ubiquitin mRNA is only modestly induced (70% increase) and peaks at 6 hr recirculation. Hsp70 mRNA is more strongly induced (more than 2-fold) and peaks at 12 hr, coincident with the time of maximal hsp70 translation previously determined. A striking temporal and anatomical pattern of hsp70 induction was demonstrated in post-ischemic brain using monoclonal antibodies considered specific for inducible forms of the hsp70 family. Control animals showed immunoreactivity which was restricted to ependymal cells lining the ventricles, and this remained unchanged after ischemia. During 24 hr recirculation after 10 min ischemia, hsp70 immunoreactivity appeared in dentate granule cells, in neurons of habenula and striatum, and in a number of basal forebrain and cortical regions. At 48 hr intense reactivity was evident in CA3 neurons of hippocampus. By 96 hr immunoreactivity was restricted to some residual staining of CA3 with strong labeling of entorhinal and other cortical regions. It is of interest that positive cells are found in hippocampus and other limbic structures, circuitry which may be the anatomical substrate for proposed excitotoxic mechanisms of neuronal loss after ischemia. Accumulation of hsp70 was apparent in CA3 and dentate granule cells which survive transient ischemia, but was greatly attenuated in CA1 neurons which do not. This heterogeneity in hsp70 induction may reflect variations in post-ischemic metabolic stress as well as in the response to stress of various cell populations.