关键词: ³¹P磁共振波谱, 心肌缺血, 代谢,  高氯酸, 萃取

Abstract:

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 region), frozen with liquid nitrogen, pulverized and extracted with perchloric acid (PCA). The extracts obtained were lyophilized, re-dissolved in ²H₂O and analyzed by ³¹P 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) ³¹P MRS on PCA extracts can be used to study energy and phospholipids metabolism in myocardium; (2) The normal appearing region showed metabolite changes, suggesting that energy 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.

Key words: ³¹P MRS, myocardial ischemia, metabolism, perchloric acid, extraction