Takemoto O, Tomimoto H, Yanagihara T
Department of Neurology, Mayo Clinic, Rochester, Minn, USA.
Stroke. 1995 Sep;26(9):1639-48. doi: 10.1161/01.str.26.9.1639.
Proto-oncogene activation and induction of heat shock protein (HSP) occur in response to various stimuli to brain, but the role in neuronal survival after cerebral ischemia remains uncertain. We compared the extent of insults and induction of c-fos and c-jun gene products (c-FOS and c-JUN) as well as HSP in ischemic and postischemic gerbil brains immunohistochemically.
Common carotid arteries of Mongolian gerbils were occluded for 5 or 15 minutes and recirculated for 0 minutes to 7 days. Antibodies for c-FOS, c-JUN, and HSP 70 were used for immunohistochemistry, and positive reactions were semiquantitatively analyzed. The presence of ischemic and postischemic lesions was ascertained with an antibody for microtubule-associated proteins.
After ischemia for 15 minutes and reperfusion, c-FOS was induced promptly after 1 to 6 hours in pyramidal cells of the CA3 and CA4 regions, while c-JUN became visible in the same areas after recirculation for 4 to 48 hours. HSP 70 was detected after recirculation for 24 hours in the CA3 region. In layers I and II of the cerebral cortex, c-FOS and c-JUN peaked at 3 hours and HSP 70 at 96 hours. Induction of these proteins was absent or negligible in the areas that developed ischemic or postischemic lesions, including the subiculum-CA1 and CA1 regions of the hippocampus and layers III/IV and Vb/VI of the cerebral cortex. After shorter ischemia for 5 minutes and reperfusion, c-FOS and c-JUN were rapidly induced at 15 minutes to 1 hour except for the subiculum-CA1 and CA1 regions of the hippocampus. Induction of HSP 70 did not occur for 24 hours and was noted only in the hippocampus.
Induction of c-FOS and c-JUN occurred in the areas surviving after transient cerebral ischemia, but the extent of induction and the latent period varied depending on the duration of the insult and the location. In the areas with ischemic or postischemic damage detected by loss of the reaction for microtubule-associated proteins, the induction of c-FOS and c-JUN was either absent or minimal, suggesting that active induction of those immediate early gene products occurred early in surviving neurons. On the other hand, the induction of HSP 70 did not occur until reperfusion for 24 hours and actively occurred only in the areas with earlier induction of c-FOS and/or c-JUN, suggesting that the induction of HSP 70 occurred in neurons that survived to that point, but it did not participate in early responses for neuronal survival after global cerebral ischemia.
原癌基因激活和热休克蛋白（HSP）的诱导可响应大脑受到的各种刺激而发生，但在脑缺血后神经元存活中的作用仍不确定。我们通过免疫组织化学比较了缺血和缺血后沙鼠脑内损伤程度以及c-fos和c-jun基因产物（c-FOS和c-JUN）以及HSP的诱导情况。
阻断蒙古沙鼠的双侧颈总动脉5或15分钟，再灌注0分钟至7天。使用针对c-FOS、c-JUN和HSP 70的抗体进行免疫组织化学，并对阳性反应进行半定量分析。用微管相关蛋白抗体确定缺血和缺血后病变的存在。
缺血15分钟并再灌注后，CA3和CA4区锥体细胞在1至6小时后迅速诱导出c-FOS，而c-JUN在再灌注4至48小时后在同一区域可见。CA3区在再灌注24小时后检测到HSP 70。在大脑皮层的I层和II层，c-FOS和c-JUN在3小时达到峰值，HSP 70在96小时达到峰值。在出现缺血或缺血后病变的区域，包括海马的下托-CA1和CA1区以及大脑皮层的III/IV层和Vb/VI层，这些蛋白的诱导不存在或可忽略不计。缺血5分钟并再灌注时间较短时，除海马的下托-CA1和CA1区外，c-FOS和c-JUN在15分钟至1小时迅速诱导。HSP 70在24小时内未诱导产生，仅在海马中观察到。
短暂性脑缺血后存活区域诱导出c-FOS和c-JUN，但诱导程度和潜伏期因损伤持续时间和位置而异。在通过微管相关蛋白反应缺失检测到缺血或缺血后损伤的区域，c-FOS和c-JUN的诱导不存在或最小，这表明这些即刻早期基因产物的活跃诱导发生在存活神经元的早期。另一方面，HSP 70直到再灌注24小时才诱导产生，且仅在c-FOS和/或c-JUN早期诱导的区域活跃发生，这表明HSP 70的诱导发生在存活到该时刻的神经元中，但它不参与全脑缺血后神经元存活的早期反应。
