大鼠急性缺血心肌31P磁共振波谱的基础研究

利用³¹P磁共振波谱（MRS）检测了急性缺血心肌组织提取物中高能磷酸化合物的变化. 方法：成年SD大鼠在心肌梗塞后0、5、 20、45 min后进行取材，梗塞区、边缘区及正常区的心肌组织经高氯酸萃取后进行高分辨MRS检测. 结果：梗塞区，缺血5 min PCr/Pi比值下降到对照组的12 ％；20 min ATP/Pi 比值下降至0.05，Pi/EPP比值上升至0.8；45 min 梗塞区PDE/ATP上升至1.93，与45 min心肌的不可逆损伤超微结构相吻合. 边缘区各代谢产物出现改变的程度要小于梗塞区，大于正常区. 正常区也有能量代谢的改变. 结论：心肌组织的³¹P MRS能够反映心肌缺血后心肌不同部位的动态能量代谢改变. PDE/ATP是判断心肌不可拟性损伤的可靠指标.

A 31P MAGNETIC RESONANCE SPECTROSCOPY STUDY OF RAT MYOCARDIUM AFTER ACUTE ISCHEMIA

Myocardial ischemia with different durations (0 min, 5 min, 20 min and 45 min) was induced in adult male SD rats. The myocardium was then harvested,. divided into three parts (the infarcted region, the border zone and the normal appearing re- gion), frozen with liquid nitrogen, Pulverized and extracted with perchloric acid (PCA). The extracts obtained were lyophilized, re-dissolved in ~2H_2O and analyzed by ~(31)P MRS. The results show that, in the infarcted region, the PCr/Pi ratio decreased to 12 % of control after 5 min ischemia; the ATP/Pi ratio decreased to 0. 05 and the Pi/ EPP ratio increased to 0. 8 after 20 min ischemia; the PDE/ATP ratio reached 1. 93 after 45 min ischemia. The normal region also showed metabolite changes. The PCr/Pi ratio after 5 min ischemia and the ATP/Pi ratio after 45 min ischemia decreased to 20 % and 43 % of those in the normal appearing region respectively. Conclusions: (1) ~(31) P MRS on PCA extracts can be used to study energy and phospholipids metabolism in myocardi- um; (2) The normal appearing region showed metabolite changes, suggesting that ener- gy reserve and utilization decreased in this region; (3) The PDE/ATP ratio may be used as a marker for irreversible ischemic injuries in rat myocardium.