Intracisternal increase of superoxide anion production in a canine subarachnoid hemorrhage model.
Intracisternal increase of superoxide anion production in a canine subarachnoid hemorrhage model.
复制标题
犬蛛网膜下腔出血模型中脑池内超氧阴离子产生的增加。
作者：
Mori,T;Nagata,K;Town,T;Tan,J;Matsui,T;Asano,T
背景和目的——活性氧（ROS）被认为是蛛网膜下腔出血（SAH）后脑血管痉挛发病机制的主要原因。然而，由于脑血管痉挛中ROS的直接证据尚未得到证实，我们试图使用改良的Karnovsky锰/二氨基联苯胺(Mn2+/DAB)技术来证实SAH后蛛网膜下腔中超氧阴离子(·O2−)的产生。方法——根据24只比格犬的两次出血模型诱导SAH或假手术。 SAH或假手术后第2或7天，给狗鞘内注射含有Mn2+和DAB的缓冲液，并准备脑干用于光学和电子显微镜检查。还分别使用特恩布尔蓝或柏林蓝染色检查了亚铁 (Fe2+) 或三价铁 (Fe3+) 铁离子与·O2− 可能的共定位。 结果 - 光学显微镜显示 SAH 后第 2 天和第 7 天，蛛网膜下腔血肿、动脉周围间隙和基底动脉外膜内有无定形琥珀色沉积物。 ·通过添加超氧化物歧化酶或从灌注液中排除 Mn2+ 或 DAB 来消除 O2- 沉积物，从而证实了反应的特异性。这些沉积物与指示 Fe2+ 和 Fe3+ 的蓝色反应沉积物共定位。在蛛网膜下腔内，·O2− 指示电子致密细颗粒优先位于退化红细胞周围，其次是浸润巨噬细胞和中性粒细胞。结论——我们显示了 SAH 后蛛网膜下腔中·O2− 和 Fe2+/Fe3+ 铁离子生成增加的直接证据，进一步支持了 ROS 在 SAH 后脑血管痉挛中的致病作用。 SAH。
Background and Purpose—Reactive oxygen species (ROS) are thought to be primary in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). However, as direct evidence of ROS has not yet been demonstrated in cerebral vasospasm, we sought to substantiate superoxide anion (·O2−) generation in the subarachnoid space after SAH using a modification of Karnovsky’s manganese/diaminobenzidine (Mn2+/DAB) technique.Methods—SAH or sham operation was induced according to a 2-hemorrhage model in a total of 24 beagle dogs. On day 2 or 7 after SAH or sham operation, dogs were intrathecally infused with buffer containing Mn2+and DAB, and the brain stem was prepared for light and electron microscopy. Possible colocalization of ferrous (Fe2+) or ferric (Fe3+) iron ions with ·O2−was also examined with the use of Turnbull blue or Berlin blue staining, respectively.Results—Light microscopy revealed amorphous, amber deposits within the subarachnoid hematoma, the periarterial space, and the tunica adventitia of the basilar artery on days 2 and 7 after SAH. ·O2−deposits were eliminated by addition of superoxide dismutase or exclusion of either Mn2+or DAB from the perfusate, confirming the specificity of the reaction. These deposits were colocalized with blue reaction deposits indicating Fe2+and Fe3+. Within the subarachnoid space, ·O2−indicating electron-dense fine granules were preferentially located around degenerated erythrocytes and, secondarily, infiltrating macrophages and neutrophils.Conclusions—We show direct evidence for enhanced production of ·O2−and Fe2+/Fe3+iron ions in the subarachnoid space after SAH, lending further support to the pathogenic role of ROS in cerebral vasospasm after SAH.