| BACKGROUND: Ischemia-reperfusion injury (I/RI) to the heart occurs frequently in clinical practice. The mechanism and protective measures of I/RI had been studied widely in recent years,however, it's still unclear.The pharmacological actions of Chinese Herb Rhodiola rosea extract include enduring oxygen deficiency,antifatigue, anti-aging and improving immunity, etc.Moreover, recent studies show that it is able to regulate and protect the fuction of cardiovascular system in many ways.This experimentation is conducted to further investigate the protective effect of Salidroside which is the chief component of Rhodiola rosea on heart ischemia-reperfusion injury.OBJECTIVE: To study the effects of Salidroside pretreament on myocardial oxygen consumption and ischemia reperfusion injury in isolated rat heart and grope for the appropriate dose in this research by Langendorff apparatus,thereby offering a new measure of treating ischemia heart disease.METHODS: Twenty-four isolated rat hearts were randomly divided into four groups:C(contrast group),A1, A2 and A3(Salidroside pretreament groups),6 cases in each group. The isolated hearts were allowed to stabilize with K-H solution for 20 minutes prior to each study.For C group,the isolated hearts were perfused with K-H solution for another 10 minutes.The A1, A2 and A3 groups were switched to perfuse with 5μg/ml, 10μg/ml and 20μg/ml Salidroside solution for 10 minutes respectively. Then global ischemia was conducted by blocking the aortic flow for 25 minutes followed by reperfusion with K-H solution up to 30 minutes.Salidroside was prepared in distilled water and diluted with K-H solution to the desired concentration employed in each experiment. Heart rate ( HR) , left ventricle developed pressure(LVDP) and Maximum left ventricular pressure increase rate(dp/dt max) were determined by Biopac MP150. Lactate dehydrogenase ( LDH) and creatine kinase (CK) in the coronary effluent and coronary blood flow ( CBF) in the last minute of stabilization and the 1st,3rd,5th,10th,15th ,20th,30th minutes of reperfusion were measured . RESULTS: Compared with C group, Salidroside inhibited prominently the HR with dose response relationship(P<0.05): the HR at the end of Salidroside solution perfusion in each group was 75.79±10.88%,64.86±8.78%and 47.92±12.33% of the one in the last minute of the equilibration; Salidroside increased momently the contraction of the isolated heart(LVDP,dp/dt max)and followed by decreasing persistently to the basic level of state of equilibrium. The LVDP×HR that stands for the myocardial oxygen consumption was much lower at the last stage of Salidroside solution perfusion in A2 group (67.10%,P<0.05) and A3 group (51.20%,P<0.05) respectively, while the A1 group was no less than C group. The recovery ratio of dp/dt max in the last 5 minutes of reperfusion period was 47.57±10.07% , 55.61±8.15%, 57.54±4.35% and 31.57±3.73% in each group,namely all of the A groups were better than the contrast(P<0.05 ), in addition , A2 and A3 group was better than A1(P<0.05 ). The recovery percentage of dp/dt min was 47.28±7.33% , 60.56±17.94%, 50.16±3.63% and 34.26±4.04% in each group, all of the A groups were higher than the C group(P<0.05 ),and A2 group was better than A1 and A3(P<0.05 ). The recovery of LVDP in A1,A2, A3 group was higher(P<0.05): 76.92±18.00%,82.64±12.91% and 93.31±10.02% in each group,and A3>A2>A1(P<0.05). However the recovery of CBF in the reperfusion process was no difference in all groups(P>0.05). The release of CK and LDH was significantly lower(P<0.05) in all of A groups during reperfusion besides the first minute.CONCLUSION: Salidroside inhibits the heart rate and decreases the myocardial oxygen consumption of isolated rat heart with dose-response relationship; Salidroside possesses significantly protective effect on isolated heart ischemia-reperfusion injury ,improving the cardic contraction and and relaxation, reducing markedly the release of CK and LDH independ of concentration;10μg/ml Salidroside solution is better to the ischemia reperfusion injury heart on the whole.
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