Shimizu H, Chang L H, Litt L, Zarow G, Weinstein P R
Department of Neurological Surgery, School of Medicine, University of California, San Francisco, USA.
Magn Reson Med. 1997 Jun;37(6):833-9. doi: 10.1002/mrm.1910370606.
To record brain temperature for comparison with rectal and temporalis muscle temperatures in preliminary studies before MR spectroscopy experiments, a thermistor was inserted into the basal ganglia in eight anesthetized, ventilated, and physiologically monitored rats. The rats were placed in an MR spectrometer and subjected to 60 min of global cerebral ischemia and 2 h of reperfusion without radiofrequency (RF) pulsing. Body temperature was maintained at 37.5-38.0 degrees C (normothermia) or 36.5-37.0 degrees C (mild hypothermia). Brain temperature during ischemia, which dropped to 31.9 +/- 0.3 (hypothermia) and 33.6 +/- 0.5 degrees C (normothermia), correlated with temporalis muscle temperature (r2 = 0.92) but not with body or magnet bore temperature measurements. Ischemia reduced brain temperature approximately 1.7 degrees C in rats subjected to mild hypothermia (1 degree reduction of body temperature). Parallel MR spectroscopy experiments showed no significant difference in energy metabolites between normothermic and hypothermic rats during ischemia. However, the metabolic recovery was more extensive 20-60 min after the onset of reperfusion in hypothermic rats, although not thereafter (P < 0.05). Mild hypothermia speeds metabolic recovery temporarily during reperfusion but does not retard energy failure during global ischemia in rats.
在磁共振波谱实验前的初步研究中，为记录脑温以便与直肠温度和颞肌温度进行比较，将一个热敏电阻插入8只麻醉、通气并进行生理监测的大鼠的基底神经节。将大鼠置于磁共振波谱仪中，使其经历60分钟的全脑缺血和2小时的再灌注，期间不进行射频脉冲。体温维持在37.5 - 38.0摄氏度（正常体温）或36.5 - 37.0摄氏度（轻度低温）。缺血期间脑温降至31.9±0.3（低温）和33.6±0.5摄氏度（正常体温），与颞肌温度相关（r2 = 0.92），但与体温或磁体腔温度测量值无关。在轻度低温（体温降低1摄氏度）的大鼠中，缺血使脑温降低约1.7摄氏度。并行的磁共振波谱实验表明，在缺血期间，正常体温和低温大鼠的能量代谢物无显著差异。然而，低温大鼠在再灌注开始后20 - 60分钟代谢恢复更为广泛，尽管之后并非如此（P < 0.05）。轻度低温在再灌注期间暂时加快代谢恢复，但在大鼠全脑缺血期间并不延缓能量衰竭。
