Aronowski J, Cho K H, Strong R, Grotta J C
Department of Neurology, The University of Texas Medical School at Houston, 77030, USA.
J Cereb Blood Flow Metab. 1999 Jun;19(6):652-60. doi: 10.1097/00004647-199906000-00008.
To determine the occurrence and time-course of presumably irreversible subcellular damage after moderate focal ischemia, rats were subjected to 1, 3, 6, 9, or 24 hours of permanent unilateral middle cerebral and common carotid occlusion or 3 hours of reversible occlusion followed by 3, 6, or 21 hours of reperfusion. The topography and the extent of damage were analyzed with tetrazolium staining and immunoblot using an antibody capable of detecting breakdown of neurofilament. Neurofilament proteolysis began after 3 hours in the infarct core but was still incomplete in penumbral regions up to 9 hours. Similarly, tetrazolium-staining abnormalities were observed in the core of 50% of animals after 3 hours of ischemia. At 6 hours of permanent ischemia, infarct volume was maximal, and further prolongation of occlusion to 9 or 24 hours did not increase abnormal tetrazolium staining. In contrast to permanent ischemia and in agreement with the authors' previous demonstration of "reperfusion injury" in this model, prolongation of reperfusion from 3 hours to 6 and 21 hours after 3 hours of reversible occlusion gradually augmented infarct volume by 203% and 324%, respectively. Neurofilament proteolysis initiated approximately 3 hours after ischemia was quantitatively greatest in the core and extended during reperfusion to incorporate penumbra with a similar time course to that of tetrazolium abnormalities. These data demonstrate that, at least as measured by neurofilament breakdown and mitochondrial failure, extensive cellular damage is not present in penumbral regions for up to 9 hours, suggesting the potential for rescuing these regions by appropriate and timely neuroprotective strategies.
为了确定中度局灶性缺血后可能发生的不可逆亚细胞损伤的发生情况和时间进程，对大鼠进行了1、3、6、9或24小时的永久性单侧大脑中动脉和颈总动脉闭塞，或3小时的可逆性闭塞，随后再灌注3、6或21小时。使用能够检测神经丝断裂的抗体，通过四氮唑染色和免疫印迹分析损伤的部位和程度。神经丝蛋白水解在梗死核心3小时后开始，但在半暗带区域直至9小时仍未完全完成。同样，在缺血3小时后，50%的动物核心区域观察到四氮唑染色异常。在永久性缺血6小时时，梗死体积最大，闭塞时间进一步延长至9或24小时并未增加异常四氮唑染色。与永久性缺血相反，并且与作者之前在该模型中证明的“再灌注损伤”一致，在3小时可逆性闭塞后，再灌注时间从3小时延长至6和21小时，梗死体积分别逐渐增加203%和324%。神经丝蛋白水解在缺血后约3小时开始，在核心区域定量最大，并在再灌注期间扩展至半暗带，其时间进程与四氮唑异常相似。这些数据表明，至少通过神经丝断裂和线粒体功能衰竭来衡量，在长达9小时的时间内，半暗带区域不存在广泛的细胞损伤，这表明通过适当及时的神经保护策略有可能挽救这些区域。
