Griffith J K, Cordisco B R, Lin C W, LaManna J C
Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH 44106.
Brain Res. 1992 Feb 21;573(1):1-7. doi: 10.1016/0006-8993(92)90108-l.
Tissue acidosis is an important determinant of cell viability following cerebral ischemia. Because of the heterogeneity of tissue response to metabolic stress, a method for measuring intracellular pH (pHi) that preserves spatial information would be desirable. Histophotometry of the pH indicator dye Neutral red offers such a possibility. The purpose of our study was to determine the distribution of pHi following complete irreversible ischemia and show the correlation of mean pHi measured by Neutral red and [31P]NMR in the same brain. Three rats were studied in the anesthetized state. A pHi range was obtained by total cerebral ischemia at various pre-arrest plasma glucose concentrations. The data show that mean pHi calculated by Neutral red was strongly correlated to pHi determined from [31P]NMR (slope: 0.99 +/- 0.08; P less than 0.001, r2 = 0.96). Within each brain, 80-110 discrete samples were analyzed by histophotometry. The pHi distribution of those samples broadened in those rat brains with greater acidosis, suggesting a heterogeneity of response by the tissue to ischemia and the presence of multiple pHi pools. Our results demonstrate the need to use methods which maintain spatial resolution such as is available with histophotometry.
组织酸中毒是脑缺血后细胞活力的重要决定因素。由于组织对代谢应激反应的异质性，一种能够保留空间信息的测量细胞内pH值（pHi）的方法将是理想的。pH指示剂染料中性红的组织光度测定法提供了这样一种可能性。我们研究的目的是确定完全不可逆缺血后pHi的分布，并显示同一大脑中用中性红测量的平均pHi与[31P]核磁共振之间的相关性。对三只处于麻醉状态的大鼠进行了研究。通过在不同的预停搏血浆葡萄糖浓度下进行全脑缺血来获得pHi范围。数据表明，用中性红计算的平均pHi与由[31P]核磁共振测定的pHi密切相关（斜率：0.99±0.08；P<0.001，r2 = 0.96）。在每个大脑中，通过组织光度测定法分析了80 - 110个离散样本。在酸中毒更严重的大鼠大脑中，这些样本的pHi分布变宽，表明组织对缺血的反应存在异质性以及存在多个pHi池。我们的结果表明需要使用能够保持空间分辨率的方法，如组织光度测定法所具备的那样。
