Effect of hypoxia on traumatic brain injury in rats: Part 2. Changes in high energy phosphate metabolism.
Effect of hypoxia on traumatic brain injury in rats: Part 2. Changes in high energy phosphate metabolism.
复制标题
缺氧对大鼠脑外伤的影响：第二部分：高能磷酸盐代谢的变化。
作者：
N. Ishige;L. Pitts;L. Pogliani;T. Hashimoto;M. Nishimura;H. Bartkowski;T. James
利用体内磷 31 磁共振 (P-31 MR) 波谱研究了不同程度的缺氧对冲击损伤大鼠脑内磷酸盐代谢的影响。比较了单独缺氧、单独冲击损伤或联合冲击缺氧损伤的大鼠在损伤后 60 分钟内 P-31 MR 光谱的连续变化。单独缺氧（PaO2 为 40 mm Hg，持续 30 分钟）除了细胞内 pH 值降低外，没有引起磷光谱的显着变化。在受到冲击损伤的大鼠中，无机磷酸盐 (Pi) 的浓度增加，但磷酸肌酸 (PCr) 和 β-三磷酸腺苷 (β-ATP) 的信号没有变化，并且 PCr/Pi 的比率仅略有变化，比对照值低 7%。 5 atm流体冲击冲击损伤大鼠在PaO2 40 mm Hg缺氧条件下持续15 min时，PCr/Pi比值下降14%，显着低于单独冲击组（P小于0.05）。冲击损伤大鼠长时间缺氧（PaO2 为 40 mm Hg，持续 30 分钟）后，Pi 显着增加，PCr 和 β-ATP 信号显着降低，导致 PCr/Pi 比值显着下降至低于对照值 39%（P 小于 0.001）。较轻度缺氧（PaO2 为 50 mm Hg，持续 30 分钟）加上冲击损伤导致高能代谢物浓度变化较小，PCr/Pi 比值降至对照值以下 15%。（摘要截断为 250 字）
The effect of different degrees of hypoxia on phosphate metabolism in the brains of impact-injured rats was studied using in vivo phosphorus-31 magnetic resonance (P-31 MR) spectroscopy. Sequential changes in P-31 MR spectra within 60 minutes of insult were compared among rats with hypoxia alone, impact injury alone, or a combined impact-hypoxic insult. Hypoxia alone (PaO2 of 40 mm Hg for 30 minutes) caused no remarkable changes in phosphorus spectra except a decrease in intracellular pH. In impact-injured rats, the concentration of inorganic phosphate (Pi) increased, but signals for phosphocreatine (PCr) and beta-adenosine triphosphate (beta-ATP) did not change, and the ratio of PCr/Pi changed only slightly to 7% below control value. When rats with a fluid percussion impact injury of 5 atm were subjected to hypoxic conditions of a PaO2 of 40 mm Hg for 15 minutes, the PCr/Pi ratio decreased by 14%, a value significantly below that of the impact alone group (P less than 0.05). After longer periods of hypoxia (PaO2 of 40 mm Hg for 30 minutes) in impact-injured rats, there were marked increases of Pi and significant decreases in signals for PCr and beta-ATP, which caused a marked decrease in the PCr/Pi ratio to 39% below control values (P less than 0.001). Milder hypoxia (PaO2 of 50 mm Hg for 30 minutes) plus impact injury caused smaller changes in high energy metabolite concentrations, and the PCr/Pi ratio decreased to 15% below control values.(ABSTRACT TRUNCATED AT 250 WORDS)