The Effect And Mechanism Of Single Perfusion Of "KVP" Cardioplegia On Immature Ischemia Myocardium

The First Part The Effect of Times of Perfusion Method in"KVP"Cardioplegic Solution protecting Immature Ischemic MyocardiumObjective To evaluate the heart function of the times of"KVP"Cardioplegia perfusion on the immature rat and approach their appropriate time. Methods Adopting 32 male rats at the age of 22±2 days, the Langendorff-perfused isolated rat hearts perfused steadily 20 min. According to the different times of"KVP"cardioplegic solution perfusion on ischemia myocaidium during 90min, the experiment was divided into four groups. The first was a single perfusion ("KVP"cardioplegic solution arrested for 3min and then undergone ischemia for 87min). The second was two times and"KVP"cardioplegic solution arrested for 3min every 60min.The third also was two times, but every 45 min. The forth was three times every 30min. After ischemia for 90min, the groups all reperfused for 60min. We observed functional indexes including heart rate, diastole, contraction force, peak systolic velocity, peak diastole velocity, coronary flow. Results In the four groups, the heart function of single perfusion method in KVP solution was best in the aspect of the beat,diastole,contraction force,peak systolic velocity, peak diastole velocity, coronary flow. Conclusion Theses results indicated that single perfusion method in KVP solution may provide better myocardial protection than the multiple perfusion method in immature myocardial.The Second Part The effect and mechanism of single perfusion of"KVP"Cardioplegia on Immature Ischemia MyocardiumObjective To evaluate the myocardial protective effect of single perfusion of"KVP"cardioplegia on immature ischemic myocaidium and compare it with ST.Thomas'II cardioplegic solution, and explore the possible protective mechanism. Methods After 20 min perfusion, the immature hearts isolated from 32 male rats at the age of 22±2 days old rats were randomly divided into four groups: normal perfusion group(perfused for 150min consecutively), ischemia/reperfusion group, ST.Thomas group,"KVP"group(during ischemia, respectively perfused with Locke's solution without oxygen and glucose, ST.Thomas'II cardioplegic solution,"KVP"cardioplegic solution for 3min,reperfusion for 60min). We assessed the heart function. At the end of each experiment, we took some myocardium tissue to determine the content of Na+-K+ ATPase, Ca2+-Mg2+ ATPase, T-ATPase, superoxide dismutase, malondialdehyde, nitric oxide and observe myocardial histopathology and ultralstructure. Results Compared with ST.Thomas group,"KVP"group was lower diastole during ischemia and superior to the recovery of heart rate,contraction force,coronary flow."KVP"group avoided energy consumption,enhanced antioxigy and ensured the integrality of myocardial histology and cell ultralstructure. Conclusions"KVP"cardioplegic solution possessed better protective effects on immature ischemic than ST.Thomas'II cardioplegic solution in the aspect of metabolism,structure and function.