肾缺血预处理对未成熟心肌的保护作用

目的探讨肾缺血预处理对未成熟心肌保护的影响，为未成熟心肌的保护提供新的方法。方法建立兔Langendorff灌注模型，将18只幼兔随机分为3组，缺血／再灌注组（I／R组）：灌注15min转为工作心15min，停灌45min，恢复灌注15min改为工作心30min；心脏缺血预处理组（CIP组）：灌注15min转为工作心15min，反复2次缺血5min再灌注5min，重复I／R组的方法；肾缺血预处理组（RIP组）：反复3次阻断左肾动脉血流5min再灌注5min，取离体心脏，灌注15min转为工作心15min，重复I／R组的方法。观察血流动力学、生化等指标。结果CIP组和RIP组的冠状动脉流量（CF）、心排血量（CO）、左心室收缩压（LVSP）恢复百分率均较I／R组升高，左心室舒张期末压（LVEDP）恢复率则较I／R组降低，差异有统计学意义（P〈0.01）；三组间比较，HR、AF恢复率差异无统计学意义（P〉0.05）；RIP组与CIP组比较各指标恢复率差异无统计学意义（P〉0．05）。RIP组与I／R组比较：心肌含水量（MWC）、血清肌酸激酶（cK）和乳酸脱氢酶（LDH）漏出率、ATP含量、丙二醛（MDA）含量、超氧化物歧化酶（SOD）活性、心肌细胞内Ca^2＋含量、心肌线粒体Ca^2＋-ATPase活性、心肌线粒体Ca^2＋含量、心肌线粒体合成ATP能力差异有统计学意义（P〈0.01），RIP组和CIP组比较各项指标差异无统计学意义（P〉0.05）。结论肾缺血预处理对未成熟心肌具有心肌保护作用。

Preservation Effect of Immature Myocardium with Renal Ischemic Preconditioning in Neonatal Rabbits

Objective To investigate the immature myocardial protection effects with renal ischemic preconditioning. Methods 18 neonatal rabbits were randomly divided into three groups. Ischemic/reperfusion（I/ R） group underwent 45 min ischemia followed with 45 min reperfusion after Langendorff model performed. Cardiac ischemic preconditioning （CIP） group underwent 45 min ischemia followed with 45 min reperfusion after 5 min ischemia and then 5 min reperfusion for two times. Renal ischemic preconditioning（RIP） group underwent 45 min ischemia followed with 45 min reperfusion after renal artery obstruction for 5 min and 5 min reperfusion for three times. The left ventricular function recovery,myocardial water content （MWC）, lactate dehydrogenase （LDH） and creatine kinase （CK） leakage, malondialdehyde （MDA） content, adenosine triphosphate （ATP） content, superoxide dismutase （SOD） activity, myocardial cell Ca^2＋ Ca^2＋ ]c content, mitochondrial Ca^2＋ content Ca^2＋]m, synthesizing ATP activity of mitochondria ATP]m and Ca^2＋-ATPase activity of mitochondria Ca^2＋-ATPase]m were tested. Results The recovery of postischemic heart function in RIP group and CIP group were higher than that I/R group （P〈0. 01）. There were no significant difference of HR, AF in three groups （P〉0. 05）. There were significant difference of CF,CO,LVSP and LVEDP in RIP group and CIP group than those I/R group（P〈0.01）. There were significant difference of MWC, CK, LDH, ATP content, MDA, SOD activity, Ca^2＋ ]m content, Ca^2＋-ATPase]m, Ca^2＋]m and ATP]m in RIP group than those I/R group（P〈0.01）. There were no significant difference between RIP group and CIP group upon every index （P〉 0. 05）. Conclusion RIP has the same cardioprotection to immature myocardium as ischemic preconditioning.