Objective To investigate the effect of ischemic preconditioning(IPC) on myocardial ischemic reperfusion injury(I/R) of elderly rats. Methods Fiftysix Wistar rats, of which there were 28 aged from 21-23months(elderly rat) and 28 aged from 4-5months(young rat), were used to build isolated heart perfusion Langendorff model. The rats were divided into 7 groups with random number table（8 in each group）: adult control group, adult I/R group, adult IPC group, elderly control group, elderly I/R group, elderly IPC group and elderly enhanced IPC group. The control group underwent a 90-min perfusion without any intervention; the I/R group underwent a 30-min equilibration period, then a 30-min ischemia and a 30-min reperfusion; the IPC group underwent a 10-min equilibration period, then a 5-min ischemia for twice and a 5-min reperfusion, after that a 30-min ischemia and [CM(158-3mm]a 30-min reperfusion; the enhanced IPC group underwent a 10-min equilibration period, then a 5-min ischemia for 4-times and a 5-min reperfusion, after that a 30-min ischemia and a 30-min reperfusion. The recovery rates of cardiac output(CO), left ventricular developed pressure (LVDP), the maximum rising and descending rate of left ventricular pressure (±dp/dtmax) after a 30-min reperfusion were compared among groups. The activity of creatine kinase (CK) in coronary outflow, the level of malonyldialdehyde (MDA) and superoxide dismutase (SOD) before ischemia and after a 30min reperfusion were detected. The myocardial infarction areas were compared among groups. Results After a 30min reperfusion, compared with adult I/R group, in adult IPC group CK reduced significantly(89.48±18.72 U/L vs. 115.76±16.72 U/L，q=6.061，P lt;0.01)，the level of MDA decreased significantly（9.53±3.44 nmol/ml vs. 16.84±2.29 nmol/ml，q=7.732，P lt;0.01)，the level of SOD increased significantly（584.7±122.62 U/ml vs. 429.46±85.24 U/ml，q=4.754，P lt;0.01)，the recovery rates of CO,LVDP,+dp/dtmax and -dp/dtmax increased ignificantly(78.69%±9.68% vs. 65.10%±8.63%，83.61%±8.46% vs. 67.23±8.68%，81.68±8.68% vs. 67.89%±6.89%，89.79%±7.78% vs. 66.79%±8.46%，P lt;0.01), the myocardial infarction areas reduced significantly (5.25%±4.33% vs. 14.75%±8.02%,q=7.458，P lt;0.01)。There was no statistical significance between elderly IPC group and elderly I/R group in the above indexes（P gt;0.05）.However, There was statistical significances between elderly enhanced IPC group and I/R group. CK reduced significantly (88.60±28.32 U/L vs. 105.76±9.64 U/L，q=5.620，P lt;0.01)，the level of MDA decreased significantly（8.38±3.36 nmol/ml vs. 16.80±3.06 nmol/ml，q=7.500，P lt;0.01)，the level of SOD increased significantly（558.87±78.66 U/ml vs. 433.75±86.65 U/ml，q=7.335，P lt;0.01)，the recovery rates of CO,LVDP,+dp/dtmax and -dp/dtmax increased significantly (77.99%±10.02% vs. 66.26%±9.78%，85.59%±6.67% vs. 73.90%±6.66%，83.87%±9.98% vs. 68.90%±8.68%，86.01%±766% vs. 70.39%±7.98%，P lt;0.01)， the myocardial infarction areas reduced significantly (795%±6.32% vs. 1568%±10.36%,q=8.680， P lt;0.01). 〖WTHZ〗Conclusion The protective effect of IPC on I/R elderly rat hearts has weakened. The enhanced IPC is able to regain the protective effect of IPC on elderly rat hearts.

Citation： HAN Jinsong,WANG Zengwei,ZHU Hongyu.. The Effect of Ischemic Preconditioning on Myocardial Ischemic Reperfusion of Elderly Rats. Chinese Journal of Clinical Thoracic and Cardiovascular Surgery, 2009, 16(5): 380-384. doi: Copy