Lindsberg P J, Frerichs K U, Sirén A L, Hallenbeck J M, Nowak T S
Department of Neurology, University of Helsinki, Finland.
J Cereb Blood Flow Metab. 1996 Jan;16(1):82-91. doi: 10.1097/00004647-199601000-00010.
Cortical brain damage was produced in rats by a focal pulse from a Nd-YAG laser, and evolution of the lesion was evaluated at 30 min, and 2, 8, and 24 h with respect to microvascular perfusion, blood-brain barrier (BBB) permeability, and expression of both the heat-shock/stress protein, hsp72, and the c-fos proto-oncogene transcription factor. A double-labeling fluorescence technique employing intravenously injected Evans blue albumin (EBA) and fluorescein-labeled dextran was used to map and measure BBB damage and microvascular perfusion in fresh frozen brain sections. Hsp72 and c-fos mRNAs were localized by in situ hybridization, and the respective proteins were identified by immunocytochemistry. Parallel sections were stained for glial fibrillary acidic protein and for routine histologic examination. Striking hsp72 mRNA expression was evident by 2 h in an approximately 300 microns wide rim surrounding an area of expanding BBB damage. Increased hsp72 mRNA was observed only in regions of preserved microcirculation, where the hsp72 protein was subsequently localized exclusively in the vasculature at 24 h after the insult. Hsp72-positive endothelial cells spanned the narrow margin between the lesion and histologically normal, glial fibrillary acidic protein (GFAP)-positive cortical tissue. There was no hsp72 expression in the area of subcortically migrating edema fluid. Inductions of c-fos mRNA and Fos protein were not strikingly evident around the focal brain lesion, but were observed transiently throughout the injured hemisphere at 30 min and 2.5 h, respectively, indicating that spreading depression was triggered by the focal injury. These results are in striking contrast to those previously obtained from studies of models of focal ischemic or traumatic brain injury, which are characterized by a complex pattern of glial and neuronal hsp72 expression in the periphery of an infarct, and which suggest that the tightly demarcated lesion produced by the Nd-YAG laser lacks these components of graded injury that are evident following other types of focal brain damage.
通过钕钇铝石榴石激光的聚焦脉冲在大鼠中造成皮质脑损伤，并在30分钟、2小时、8小时和24小时评估损伤的演变情况，涉及微血管灌注、血脑屏障（BBB）通透性以及热休克/应激蛋白hsp72和原癌基因c-fos转录因子的表达。采用静脉注射伊文思蓝白蛋白（EBA）和荧光素标记葡聚糖的双标记荧光技术，对新鲜冷冻脑切片中的血脑屏障损伤和微血管灌注进行定位和测量。通过原位杂交定位hsp72和c-fos mRNA，并通过免疫细胞化学鉴定各自的蛋白质。对平行切片进行胶质纤维酸性蛋白染色和常规组织学检查。在血脑屏障损伤扩大区域周围约300微米宽的边缘处，2小时时hsp72 mRNA表达明显。仅在保存微循环的区域观察到hsp72 mRNA增加，损伤后24小时hsp72蛋白仅在脉管系统中定位。hsp72阳性内皮细胞跨越病变与组织学正常的胶质纤维酸性蛋白（GFAP）阳性皮质组织之间的狭窄边缘。皮质下迁移性水肿液区域没有hsp72表达。c-fos mRNA和Fos蛋白的诱导在局灶性脑损伤周围并不明显，但分别在30分钟和2.5小时在整个损伤半球短暂观察到，表明局灶性损伤引发了扩散性抑制。这些结果与先前从局灶性缺血或创伤性脑损伤模型研究中获得的结果形成鲜明对比，后者的特征是梗死周边胶质和神经元hsp72表达的复杂模式，这表明钕钇铝石榴石激光产生的界限分明的损伤缺乏其他类型局灶性脑损伤后明显的这些分级损伤成分。
