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 45min) was induced in adult male SD rats. The myocardium was then harvested,. dividedinto 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 to12 % 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 after45 min ischemia. The normal region also showed metabolite changes. The PCr/Pi ratioafter 5 min ischemia and the ATP/Pi ratio after 45 min ischemia decreased to 20 % and43 % of those in the normal appearing region respectively. Conclusions: (1) ~(31) P MRSon 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 usedas a marker for irreversible ischemic injuries in rat myocardium.