Germano I M, Pitts L H, Berry I, De Armond S J
Department of Neurological Surgery, University of California, San Francisco.
J Cereb Blood Flow Metab. 1988 Feb;8(1):24-31. doi: 10.1038/jcbfm.1988.4.
Relative levels of phosphate metabolites in the brain were examined in vivo by 31P magnetic resonance spectroscopy (MRS) in 50 Sprague-Dawley rats before, during, and after induction of focal permanent cerebral ischemia. After acquisition of baseline spectra, rats were subjected to injury within the core of the MR spectrometer, and 31P spectra were collected for 60 min after injury: in 7 rats, permanent, acute focal cerebral ischemia was induced (ischemia group); in 6 rats, mild hypoxia (FiO2 14%) was induced at the time of the ischemic insult and was maintained for 20 min (ischemia-hypoxia group); in 6 rats, mild hypoxia (FiO2 14%) only was induced for 20 min (hypoxia group). Control studies were performed in 25 rats. Cerebral intracellular pH, calculated from the chemical shift of inorganic phosphate (Pi), decreased immediately after injury in the ischemia and ischemia-hypoxia groups. The first 31P spectrum obtained after injury was characterized by an increase in Pi and a decrease in phosphocreatine (PCr) in the ischemia and ischemia-hypoxia groups; these changes in spectra were significantly greater in the ischemia-hypoxia group. No significant changes in adenosine triphosphate (ATP) were found in either group. Within 60 min of occlusion, 31P spectra returned toward baseline spectra in both ischemia-hypoxia and ischemia groups. No significant changes were seen in spectra of rats subjected to hypoxia alone. These results confirm that 31P MRS is a sensitive measure of early changes of high energy metabolites in focal cerebral ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)
在50只Sprague-Dawley大鼠中，通过31P磁共振波谱（MRS）在局灶性永久性脑缺血诱导前、诱导期间和诱导后对大脑中磷酸盐代谢物的相对水平进行了体内检测。在获取基线波谱后，将大鼠置于磁共振波谱仪的核心区域内进行损伤，并在损伤后60分钟收集31P波谱：7只大鼠诱导永久性急性局灶性脑缺血（缺血组）；6只大鼠在缺血性损伤时诱导轻度缺氧（FiO2 14%）并维持20分钟（缺血-缺氧组）；6只大鼠仅诱导轻度缺氧（FiO2 14%）20分钟（缺氧组）。对25只大鼠进行了对照研究。根据无机磷酸盐（Pi）的化学位移计算得出的脑细胞内pH值，在缺血组和缺血-缺氧组损伤后立即下降。缺血组和缺血-缺氧组损伤后获得的第一个31P波谱的特征是Pi增加和磷酸肌酸（PCr）减少；缺血-缺氧组波谱的这些变化明显更大。两组中三磷酸腺苷（ATP）均未发现显著变化。在闭塞60分钟内，缺血-缺氧组和缺血组的31P波谱均恢复至基线波谱。仅接受缺氧处理的大鼠波谱未见显著变化。这些结果证实，31P MRS是局灶性脑缺血中高能代谢物早期变化的敏感测量方法。（摘要截断于250字）
