ABSTRACT
Objective To explore the protective effects of erythropoietin (EPO) on cardiomyocytes against hypoxia/reoxygenation (HR) injury. Method Isolated and cultured rat eardiomyocytes were subjected to 2-hour hypoxia followed by 1 hour reoxygenation to establish model of HR injury. Cardiomyocytes were randomly divided into 4 groups: sham group, HR group, HR + EPO-treated group (EPO 10 U/ml), and HR + EPO + UO126-treated group (U0126 10?mol/L). The concentration of lactate dehydrogenase (LDH) in culture medium was detected by automatic biochemical analyzer; viability of eardiomyocytes was measured by MTT assay; apoptosis ratio was determined by TUNEL technology and Annexin-V-FITC with flow cytometer (FCM); level of extracellular signal- regulated kinase 1/2 (ERK_(1/2)) and phospho-ERK_(1/2) were measured by Western-blot analysis. Results EPO significantly decreased the leakage of LDH, enhanced activity, reduced apoptosis ratio, and increased level of phospho-ERK_(1/2).However, the effects were blocked by U0126, an inhibitor of MAPK. Conclusions EPO has the protective effects on cardiomyocytes against HR injury possibly via the mechanism of activation of ERK_(1/2) and inhibition of apoptosis.
ABSTRACT
Objective: To explore the feasibility of observing hemodynamics on ischemia/reperfusion(I/R) rat heart model in vivo by studying the changes of hemodynamics,myocardial zymogram and electrocardiogram. Methods: Twenty SD rats were randomly divided into 2 groups(n=10)(IR group and control group).The left anterior descending coronary artery was ligated or left untouched,a catheter was put into the left ventricle to trace the pressure change index and peak pressure of left ventricle,and to record ST segment changes of ECG.At the end of experiment,the levels of myocardial zymogram were determined.The results of two groups were compared. Results: Compared with control group,IR group showed reduced dp/dt max,declined LVSP,raised ST segment in ECG,and elevated myocardium zymogram. Conclusion: Our I/R rat heart model in vivo is feasible and stable to explore the cardiac hemodynamics.