预灌注期应用甲状腺素T_3对离体缺血鼠心的保护作用

Protective effects of triiodothyronine on isolated rat hearts during preperfusion

目的 评价甲状腺激素T3应用于预灌注期对离体缺血鼠心的保护作用。方法 离体鼠心被随机分为两组 ,对照组(n =8)不得到T3增补 ,实验组 (n =8)在预灌注期增补T3( 0 .6μg/L)。所有心脏都经历 2 0min预灌注 ,2 0min停搏 (停搏液用Thomas液 )和 3 0min再灌注 (灌注液用改良的K -H液 ,在 3 7℃下 )。结果 实验组再灌注 3 0min时左室发展压 (LVDP)及等容相室内压变化速率 (dp/dt)的百分恢复率及心肌超氧化物歧化酶 (SOD)均显著高于对照组 ( P <0 .0 1) ,过氧化脂质(LPO)显著低于对照组 (P <0 .0 5 ) ;对照组再灌注期心肌酶显著增加 (P <0 .0 5 ) ,而在实验组停跳前后无显著差异 ,组间相同时点心肌酶比较再灌注期实验组显著低于对照组 (P <0 .0 1) ;心肌含水量 (MWC)对照组显著高于实验组 (P <0 .0 5 ) ;心肌超微结构观察实验组显著优于对照组。结论 预灌注期T3增补显著促进了缺血后左心室功能的恢复 ,减少了缺血性损伤后心肌氧自由基的产生 ,有效地防止了心肌的缺血再灌注损伤 ,表现出显著的心肌保护作用。

WT5”BZ] Objective To evaluate the protective effects of triiodothyronine during preperfusion on isolated rat hearts. Method Isolated rat hearts ( n =16)were randomly divided into two groups:control group(n=8)without triiodothronine supplementation,experimental group( n =8)with triiodothyronine supplementation (0.6 μg/L)during preperfusion.All hearts were subjected to 20 min preperfusion,20 min ischemia (using Thomas cardioplegia )and 30 min reperfusion (using a modified Langendorff-Neely preparation with modified Krebs-Henseleit buffer at 37 ℃). Results Recovery of left ventricular developing pressure(LVDP)and its first time derivative pressure (d p /d t )and postischmic myocardial superoxides dismutase(SOD)in experimental group significantly increased compared with control group (P<0.01);There was a significant fall in postischemic myocardial lipidperoxide(LPO)in experimental group compared with the control group (P<0.05);The release of postischemic myocardial enzyme leakage(LDH HBDH)significantly increased compared with preischemia in control group (P<0.05);There was no significant difference between preischemia and postischemia in experimental group,compared with myocardial enzyme leakage of postischmic identical timepoints demonstrated it significantly decreased in control group than in experimental group(P<0.01);Myocardial water content(MWC)was significantly higher in control group than in experimental group (P<0.05);Myocardial ultrastructure was well preserved in epxperimental group compared with control group. Conclusion Triiodothyronine supplementation during preperfusion significantly improves postischemic left ventricular functional recovery,reduces the product of postischemic myocardial oxygen free radical,markedly alleviates myocardial ischemia reperfusion injury,and shows to have apparent myocardial protective effects. [WT5”HZ]