Subcellular distribution of calcium and ultrastructural changes after cerebral hypoxia-ischemia in immature rats
Subcellular distribution of calcium and ultrastructural changes after cerebral hypoxia-ischemia in immature rats
复制标题
DOI：
10.1016/s0165-3806(00)00110-3
复制
发表时间：
2000-12-29
期刊：
影响因子：
--
通讯作者：
Hagberg, H
中科院分区：
文献类型：
--
作者：
Puka-Sundvall, M;Gajkowska, B;Hagberg, H
最近的数据表明，线粒体对钙的调节在导致缺氧缺血性脑损伤的过程中至关重要。目的是研究新生大鼠缺氧缺血后钙的亚细胞分布与超微结构变化的相关性。对 7 天大的大鼠进行永久性单侧颈动脉结扎，并暴露于缺氧（氮气中含 7.7% 氧气）90 分钟。再灌注30分钟、3小时或24小时后对动物进行灌注固定。切片取样用于光学显微镜和电子显微镜结合草酸盐-焦锑酸盐技术。在回流 30 分钟和 3 小时时，在内质网、细胞质、细胞核中检测到钙逐渐积累，最明显的是在损伤核心区域灰质神经元的线粒体基质中。一些线粒体出现相当程度的肿胀，在回流 3 小时时直径达到几微米，而大多数线粒体似乎受到中度影响。在许多线粒体严重肿胀并伴有钙沉积的细胞的细胞核中观察到染色质浓缩。在退化细胞中观察到从坏死到凋亡的一系列形态学特征。 24小时后，根据线粒体和质膜的破裂以及细胞电子密度的普遍降低判断，大脑皮层出现了广泛的损伤。在损伤核心区域的白质中，轴突元件表现出充满焦锑酸钙沉积物的静脉曲张样肿胀。此外，薄髓鞘富含钙。许多少突胶质细胞样细胞表现出凋亡形态，细胞质萎缩，染色质浓缩，而星形胶质细胞坏死未见。总之，再灌注 3 小时后，通常在神经元细胞中发现明显肿胀的“巨大”线粒体，其中含有大量钙，核染色质凝结。讨论了与线粒体通透性转变和细胞凋亡过程激活相关的结果。 (C) 2000 Elsevier Science B.V. 保留所有权利。
Recent data imply that mitochondrial regulation of calcium is critical in the process leading to hypoxic-ischemic brain injury. The aim was to study the subcellular distribution of calcium in correlation with ultrastructural changes after hypoxia-ischemia in neonatal rats. Seven-day-old rats were subjected to permanent unilateral carotid artery ligation and exposure to hypoxia (7.7% oxygen in nitrogen) for 90 min. Animals were perfusion-fixed after 30 min, 3 h or 24 h of reperfusion. Sections were sampled for light microscopy and electron microscopy combined with the oxalate-pyroantimonate technique. At 30 min and 3 h of reflow, 3 progressive accumulation of calcium was detected in the endoplasmic reticulum, cytoplasm, nucleus and, most markedly, in the mitochondrial matrix of neurons in the gray matter in the core area of injury. Some mitochondria developed a considerable degree of swelling reaching a diameter of several mum at 3 h of reflow whereas the majority of mitochondria appeared moderately affected. Chromatin condensation was observed in nuclei of many cells with severely swollen mitochondria with calcium deposits. A whole spectrum of morphological features ranging from necrosis to apoptosis was seen in degenerating cells. After 24 h, there was extensive injury in the cerebral cortex as judged by breaks of mitochondrial and plasma membranes, and a general decrease of cellular electron density. In the white matter of the core area of injury, the axonal elements exhibited varicosity-like swellings filled with calcium-pyroantimonate deposits. Furthermore, the thin myelin sheaths were loaded with calcium. Numerous oligodendroglia-like cells displayed apoptotic morphology 'with shrunken cytoplasm and chromatin condensation, whereas astroglial necrosis was not seen. In conclusion, markedly swollen 'giant' mitochondria with large amounts of calcium were found at 3 h of reperfusion often in neuronal cells with condensation of the nuclear chromatin. The results are discussed in relation to mitochondrial permeability transition and activation of apoptotic processes. (C) 2000 Elsevier Science B.V. All rights reserved.