肾缺血预处理对未成熟心肌保护作用的研究

①目的　研究肾缺血预处理对未成熟心肌保护作用 ,探讨未成熟心肌保护方法。②方法　建立心脏缺血预处理 (IP)和肾缺血预处理 (RIP)兔Langendorff灌注模型。将兔随机分为 3组。缺血 再灌注组 (I R组 ) :在Langendorff模型基础上 ,灌注 15min转为工作心 15min ;IP组 :在Langendorff模型基础上 ,灌注 15min转为工作心 15min ,反复 2次缺血 5min再灌注 5min ;RIP组 :反复 3次阻断左肾动脉血流 5min再灌注 5min ,建立模型 ,灌注 15min转为工作心 15min ;然后各组全心停止灌注 4 5min ,恢复灌注 15min改为工作心 30min。以左心室功能恢复情况、心肌含水量 (MWC)、血清肌酸激酶 (CK)和乳酸脱氢酶 (LDH)漏出率、心肌组织ATP和丙二醛 (MDA)含量、超氧化物歧化酶 (SOD)活性、心肌细胞内Ca2 + 含量、心肌线粒体Ca2 + ATPase活性及其Ca2 + 含量、心肌线粒体合成ATP能力 { ATP]m}作为观察指标。③结果　RIP组和IP组左室功能恢复百分率高于I R组 (F =4 .6 7～6 .0 3,q =2 .6 0～ 3.12 ,P <0 .0 5 ) ,RIP组和IP组比较差异无显著性 (q =1.2 3～ 1.98,P >0 .0 5 ) ;RIP组和IP组MWC低于I R组 (F =5 .6 8,P <0 .0 5 ) ,RIP组和IP组比较差异无显著性 (q =1.6 5 ,P >0 .0 5 ) ;RIP组和IP组MDA含量、CK和LDH漏出率、ATP含

IMMATURE CARDIOPROTECTION WITH RENAL ISCHEMIC PRECONDITIONING IN NEONATAL RABBITS

Objective To study the effects of renal ischemic preconditioning on immature myocardial protection. Methods Langendorff reperfusion models of cardiac ischemic preconditioning(IP) and renal ischemic preconditioning(RIP) were established in 18 neonatal rabbits. The rabbits were randomly divided into three groups. Those in the ischemic/reperfusion(I/R) group underwent 15 min of ischemia after 15 min of reperfusion and those in the IP group underwent 15 min of ischemia after 15 min of reperfusion, and 5 min of ischemia and 5 min of reperfusion for two times. Those in the RIP group underwent 45 min of ischemia after 15 min of reperfusion, and 5 min of renal artery obstruction and 5 min of reperfusion for three times. The left ventricular function recovery, myocardial water content(MWC), lactate dehydrogenase(LDH) and creatine kinase(CK) leakage, malondiadehyde(MDA) content, adenosine triphosphate(ATP) content, superoxide dismutase(SOD) activity, myocardial cell Ca 2+ {Ca 2+ ] c}content, mitothondial Ca 2+ content {Ca 2+ ] m}, synthesizing ATP activity of mitothondia{ATP] m} and Ca 2+ -ATPase activity of mitothondia{Ca 2+ -ATPase] m} were tested. Results The recovery rate of postischemic heart function in RIP group and IP group was higher than that of I/R group (F=4.67-6.03,q=2.60-3.12, P<0.05). MWC in RIP group and IP group were lower than that of I/R group (F=5.68,P<0.05). Significant difference existed between ATP content, SOD activity,ATP] m, Ca 2+ ] c content, Ca 2+ ] m and Ca 2+ -ATPase] m in RIP group and IP group and that in I/R group (F=8.43-28.40,q= 4.82- 23.62, P<0.01). No significant difference was found between RIP and IP groups (q=1.03-1.82, P>0.05). Conclusion RIP has the same cardioprotection to immature myocardium as IP.