Analysis of pr- ram of porcine cardiac ischemia and the recovery process in coronary arterial occlusion and recanalization using 31P-MRS

为了明确缺血心肌的代谢异常，我们采用动脉压和呼吸门控的体内31P磁共振波谱法，对无侧支循环的缺血猪心脏中高能磷酸盐、无机磷酸盐和细胞内pH的变化进行了连续定量的评价。同时修改方案，将普萘洛尔预处理（0.6 mg/kg静脉注射）和卡替洛尔治疗前后（10mug/kg静脉注射）作为β受体阻滞剂和维拉帕米（200mug/kg），以确定它们对缺血心肌代谢的影响。在未治疗组，磷酸肌酸在缺血后20分钟迅速耗尽；40分钟后，ATP和细胞内pH分别逐渐下降到对照的10 11%和5.90 0.26，无机磷酸盐上升到对照的303 43%。在普萘洛尔、维拉帕米和卡替洛尔预处理组，阻断20分钟时ATP浓度升高，阻断40分钟时保护作用消失。对照组与处理组双产物无显著差异。这表明-受体阻滞剂和钙拮抗剂对缺血心肌的有益作用是由于对存活的缺血心肌细胞的直接作用。闭塞20分钟再灌注时，磷酸肌酸、pH、无机磷酸盐迅速恢复正常。对照组和治疗后组在再灌注120分钟时ATP水平无明显变化。预处理组在再灌注120分钟后ATP浓度恢复正常。这表明，有益的效果是由于在咬合期间的保护作用。

In an attempt to define the metabolic abnormalities of ischemic myocardium, the changes in high energy phoshates, inorganic phosphate and intracellular pH were serially and quantitatively evealuated in ischemic porcine hearts habing no collateral circulation using arterial pressure and respiration gated in vivo 31P magnetic resonance spectroscopy. The protocol was also modified for propranolol pretreatment (o.6mg/kg i.v.) and carteolol pre-and post-treatment (10mug/kg i.v.) as beta-blockers and verapamil (200mug/kg) to define their effects on the metabollsm of ischemic myocardium. In the non-treated group, creatine phosphate was repidly depleted by 20 miutes after ischemia; by 40 minutes, ATP and inttacellular pH gradually decreased to 10 11% of control and to 5.90 0.26, respectively, and inorganic phosphate rose to 303 43% of control. In the propranolol, and verapamil and carteolol pre-treated-group, the concentrations of ATP were higher at 20 minute occlusion, and the protective effect disappeared at 40 minute occlusion. There was no significant difference of double product between control and treated groups. This suggests that the beneficial effect of beta-blocker and Ca antagonist on ischemic myocardium is due to direct effect to viable ischemic myocytes. In reperfusion after 20 minute occlusion, creatine phosphate, pH and inorganic phosphate were normalized rapidly. In control and post treated group, ATP level did not change ecen in 120 minute reperfusion. In pretreated group, however, the concentration of ATP was normalized after 120 minute of reperfusion. This suggested that the beneficial effect is due to the protective effect during occlusion.