Matz P G, Sundaresan S, Sharp F R, Weinstein P R
Department of Neurosurgery, University of California at San Francisco, USA.
J Neurosurg. 1996 Jul;85(1):138-45. doi: 10.3171/jns.1996.85.1.0138.
Current experimental research on subarachnoid hemorrhage (SAH) has been limited by the lack of a small-animal model that physiologically resembles SAH and consistently demonstrates acute and delayed cellular injury. Recently, a model for inducing SAH by endovascular perforation of the internal carotid artery has been developed in the rat. This model physiologically resembles SAH. However, little histological data detailing cellular injury after SAH are available in this or other models. Using immunocytochemistry, the authors investigated the induction of the 70-kD heat shock protein, HSP70, a sensitive marker for cellular stress or injury in the brain, 1 and 5 days following endovascular SAH. The authors also used the conventional histological techniques of cresyl violet and hematoxylin and eosin staining to investigate cellular damage 1 and 5 days after the endovascular SAH. One day following the SAH, HSP70 was induced in all six animals examined in multiple anatomical regions, including the basal forebrain, thalamus, neocortex, striatum, and hippocampus. This HSP70 induction was observed in multiple vascular distributions bilaterally. Immunostaining with HSP70 occurred primarily in neurons but also was observed in glia and endothelium. Five days after the SAH, a similar but more intense pattern of HSP70 immunostaining was observed in all eight animals examined. Specifically, HSP70 immunoreactivity was observed in at least one region of the hippocampus more often at 5 days (six of eight animals) than at 1 day (one of six animals, p < 0.05, one-tailed Fisher's exact test). No HSP70 immunostaining was observed in control animals at 1 day or at 5 days. Conventional histology demonstrated foci of ischemic neuronal damage and cellular necrosis; however, HSP70 immunocytochemistry detailed cellular injury far better than conventional histology in all animals tested at both 1 day and 5 days. Our results demonstrate that HSP70 is induced in multiple regions and cell types 1 day and 5 days following endovascular SAH. Because ischemia is a known inducer of stress genes, the authors propose that acute and delayed ischemia are the processes responsible for the induction of HSP70 that was observed at 1 day and 5 days, respectively. Investigation of HSP70 induction following endovascular SAH may also serve as the basis for a new, inexpensive animal model to assess potential therapeutic interventions.
目前关于蛛网膜下腔出血（SAH）的实验研究受到限制，因为缺乏一种生理上类似于SAH且能持续显示急性和迟发性细胞损伤的小动物模型。最近，在大鼠中建立了一种通过颈内动脉血管内穿孔诱导SAH的模型。该模型在生理上类似于SAH。然而，在这个模型或其他模型中，关于SAH后详细的细胞损伤组织学数据很少。作者使用免疫细胞化学方法，研究了血管内SAH后1天和5天，70-kD热休克蛋白HSP70的诱导情况，HSP70是大脑细胞应激或损伤的敏感标志物。作者还使用了甲酚紫以及苏木精和伊红染色的传统组织学技术，来研究血管内SAH后1天和5天的细胞损伤情况。SAH后1天，在检查的所有6只动物的多个解剖区域，包括基底前脑、丘脑、新皮层、纹状体和海马体中均诱导出了HSP70。在双侧的多个血管分布区域均观察到了这种HSP70的诱导。HSP70免疫染色主要发生在神经元中，但在神经胶质细胞和内皮细胞中也有观察到。SAH后5天，在检查的所有8只动物中观察到了类似但更强烈的HSP70免疫染色模式。具体而言，在5天时，在至少一个海马区域观察到HSP70免疫反应性的动物更多（8只动物中有6只），而在1天时（6只动物中有1只），p < 0.05，单尾Fisher精确检验。在1天或5天时，对照动物中未观察到HSP70免疫染色。传统组织学显示有缺血性神经元损伤和细胞坏死灶；然而，在1天和5天测试的所有动物中，HSP70免疫细胞化学比传统组织学更能详细地显示细胞损伤情况。我们的结果表明，血管内SAH后1天和5天，HSP70在多个区域和细胞类型中被诱导。由于缺血是应激基因的已知诱导因素，作者提出急性和迟发性缺血分别是导致在1天和5天观察到的HSP70诱导的过程。对血管内SAH后HSP70诱导的研究也可能作为一种新的、廉价的动物模型的基础，以评估潜在的治疗干预措施。
