Myocardial Functional Recovery and Metabolic Status in Isolated Reperfused Rabbit Heart: Effects of Glucose Concentration and Temperature on Cardioplegia

離體兔心再灌注的功能恢復及心肌代謝狀態：心臟麻痺時葡萄糖的濃度與溫度效應

甯學寒(Xue-Han Ning) ； Xinxin Ding ； Keith F. Childs ； Steven F. Bolling

《慈濟醫學雜誌》 7卷4期 (1995/12) Pp. 243-260

https://doi.org/10.6440/TZUCMJ.199512.0243

摘要

To test the hypothesis that a beneficial effect of glucose in cardioplegia depends on metabolic utilization of glucose, 164 isolated, perfused rabbit hearts were subjected to 120 min of cardioplegic ischemia at 34ºC. Functional recovery was reflected by left ventricular developed pressure (DP), dP/dtmax and the product of heart rate and DP as % of preischemic values during reperfusion. At 34ºC ischemia, hearts treated with 5.5, 11, 22, 44, and 88 mM glucose showed significantly better functional recovery than those treated with 0 and 1.4 mM glucose, with 22 mM demonstrating optimal recovery. Subsepuently, the effect of 22 mM glucose (GLU) was compared with 22 mM mannitol (MAN), used asan osmolar control. After 120 min of ischemia at 34ºC, lactate and CO2 levels were 4.6± mM* and 2.32±0.50mM* in GLU and 2.1±0.34mM and 0.97±0.22 mM in MAN and myocardial pH was lower in GLU (6.14±0.26*) than in MAN (6.77±0.24, *=p＜0.05). At 15 Min of reperfusion, myocardial ATP was higher in GLU than in MAN (10.12±0.70* vs 1.85±1.00µmoVg dry tissue, respectively) and recovery of left ventricular developed pressure and dP/dt max was better in GLU (64.2±16.1%* and 63.5±13.2%*) than in MAN (11.3±5.4% and 9.9±4.6%). However, during 4ºC ischemia both functional recovery and ATP level showed no significant differences between GLU and MAN. Furhermore, improvements in functional recovery were not observed when myocardial pH was only lowered by the addition of histidine or CO2 There was a good correlation between DP recovery and ATP level (R2=0.80). In conclusion, the beneficial effect of glucose in cardioplegia is concentration and temperature-dependent; myocardial ATP concentration is a critical factor for functional recovery.

關鍵字

ATP ； 心肌缺血 ； 心肌代謝 ； 心臟麻痺 ； 低溫 ； 重灌注 ； 心肌pH ； 乳酸 ； 二氧化碳 ； 腺苷 ； 組胺酸

並列摘要

To test the hypothesis that a beneficial effect of glucose in cardioplegia depends on metabolic utilization of glucose, 164 isolated, perfused rabbit hearts were subjected to 120 min of cardioplegic ischemia at 34ºC. Functional recovery was reflected by left ventricular developed pressure (DP), dP/dtmax and the product of heart rate and DP as % of preischemic values during reperfusion. At 34ºC ischemia, hearts treated with 5.5, 11, 22, 44, and 88 mM glucose showed significantly better functional recovery than those treated with 0 and 1.4 mM glucose, with 22 mM demonstrating optimal recovery. Subsepuently, the effect of 22 mM glucose (GLU) was compared with 22 mM mannitol (MAN), used asan osmolar control. After 120 min of ischemia at 34ºC, lactate and CO2 levels were 4.6± mM* and 2.32±0.50mM* in GLU and 2.1±0.34mM and 0.97±0.22 mM in MAN and myocardial pH was lower in GLU (6.14±0.26*) than in MAN (6.77±0.24, *=p＜0.05). At 15 Min of reperfusion, myocardial ATP was higher in GLU than in MAN (10.12±0.70* vs 1.85±1.00µmoVg dry tissue, respectively) and recovery of left ventricular developed pressure and dP/dt max was better in GLU (64.2±16.1%* and 63.5±13.2%*) than in MAN (11.3±5.4% and 9.9±4.6%). However, during 4ºC ischemia both functional recovery and ATP level showed no significant differences between GLU and MAN. Furhermore, improvements in functional recovery were not observed when myocardial pH was only lowered by the addition of histidine or CO2 There was a good correlation between DP recovery and ATP level (R2=0.80). In conclusion, the beneficial effect of glucose in cardioplegia is concentration and temperature-dependent; myocardial ATP concentration is a critical factor for functional recovery.

並列關鍵字

Adenosine ； ATP ； carbon dioxide ； cardioplegia ； contracture ； histidine ； hypothermia ； lactate ； myocardial ischemia ； myocardial metabolism ； myocardial pH ； reperfusion