支链氨基酸对大鼠离体心肌相对缺血/再灌注损伤的保护作用

PROTECTON OF BRANCHED CHAIN AMINO ACID AGAINST RELATIVE ISCHEMIA/REPERFUSION INJURY IN ISOLATED RAT MYOCARDIUM

目的探索支链氨基酸对心肌相对缺血/再灌损伤的保护作用,为研究抗心肌损伤的保护措施提供依据。方法Wistar大鼠24只,随机分为对照组(CN)、相对缺血损伤组(IRI)和相对缺血损伤+支链氨基酸组(BCAA)。用高频阈上电刺激3组大鼠离体心脏,模拟离体心肌相对缺血/再灌注损伤,采用Pclab生物信号采集处理系统测定相对缺血损伤后的心率脉压乘积(PRP)、左心室收缩压变化速率(+Dp/dt max)和舒张压变化速率(-Dp/dt max)的恢复率;改良硫代巴比妥酸法测定冠脉流出液和心肌组织匀浆液中丙二醛(MDA)含量;生化自动分析仪检测肌酸激酶(CK)和乳酸脱氢酶(LDH)活性。结果BCAA组PRP为(70.33±7.03)%,高于IRI组PRP〔(42.89±5.10)%〕(P<0.01);BCAA组的+DP/dt max-、Dp/dt max恢复率,优于IRI组(P<0.05);BCAA组的冠脉流出液和心肌组织中的MDA含量、CK和LDH活性,低于IRI组(P<0.05),而BCAA组的心肌超氧化物歧化酶(SOD)活性为(43.13±7.10)U/mL,高于IRI组〔(34.66±3.68)U/mL〕(P<0.05)。结论BCAA对心肌相对缺血/再灌损伤具有一定的保护作用。

Objective To explore the protective effect of branched chain amino acid （BCAA） on isolated rat heart with ischemia/reperfusion injury, so as to provide scientific basis for studying the measures against myocardial injury. Methods Twenty-four Wistar rats were randomly divided into 3 groups （each 8） ： control group, ischemia group, BCAA group. The myocardiac relative ischemia/reperfusion models in vitro were set up by applying weak current to stimulate isolated rat hearts. During pre-ischemia, post-ischemia 15 min and post-ischemia 30 min, the coronary fluid was collected for testing contens of MDA and activities of both CK and LDH. Cardiac functional indexes were recorded by Pclab. The pressure-rate product（PRP）, maximal rate of increase in left ventricular pressure（ ＋ Dp/dtmax） and maximal rate of decline in left ventricular pressure（-Dp/dt max） were caculated after ischemia. Results PRP in BCAA group[ （70.33 ± 7.03） % ] was higher than that in ischemia group[ （42.89 ± 5.10） % ], （ P 〈 0.01 ）. ＋ DP/dtmax ,-Dp/dtmax in BCAA group were also better than in ischemia group（ P 〈 0.05）. MDA content, CK and LDH activities both in coronary fluid and in myocardium homogenate of BCAA group were lower than those of the ischemia group, while SOD activity in myocardium of BCAA group [ （43.13 ± 7.10）U/mL ] were higher than that of ischemia group[ （34.66 ±3.68）U/mL ], （ P 〈 0.05）. Conclusion To some extent, BCAA could protect the myocardium from isehemia/reperfusion injury.