The Effects Of Erythropoietin On Left Ventricular Function And Ventricular Weight In Rats With Acute Myocardial Infraction

Objective: After acute myocardial infarction (AMI), the hemodynamics is abnormal, cardiac function decreasing, following ventricular remodeling, and then heart failure (HF), eventually leading to death. Currently, there is no effective treatment, so the prevention of heart failure is essential. Hemodynamic and ventricular remodeling are important factors that affects heart failure after AMI. Both improvement of the hemodynamic status and ventricular remodeling reducing may affect the prognosis of patients. On the other hand, it has been confirmed that erythropoietin (EPO) has the effect to promote Erythrocyte. As a cytoprotection factor,EPO has a strongly cytoprotective action to the injury caused by multi-organ ischemia-reperfusion and toxic stimulation of inflammatory factor ,and it can prevent apoptosis of endotheliocyte and cadiocyte,delay the process of cell aging to apoptosis, inhibit ventricular remodeling, promote angiogenesis and thus play an important role in cardiovascular protection.In this study , a animal model of AMI was used, and followed treatment with recombinant human EPO (rhEPO). hemodynamic parameters, plasma brain natriuretic peptide (BNP) concentrations and relative ventricular weight were obtained after AMI, and the effects of EPO on left ventricular function and ventricular remodeling were evaluated further.Methods: 54 healthy male SD rats were recruited and divided into 3 groups randomly: sham-operated group,AMI group and EPO group. Rat models of AMI were induced by ligating left anterior decending coronary artery. The rats in EPO group were treated with intraperitoneal injection of rhEPO (5000IU/kg) daily 24 hours after operation,for 7 days. The hemodynamic parameters were determined 24 hours, 1 week and 3 weeks after ligation respectively, which included systolic pressure (SP), diastolic pressure (DP), left ventricular systolic pressure (LVSP) , left ventricular diastolic pressure (LVDP) , maximal rate of increase of ventricular pressure(+dp/dt) and maximal rate of decrease of ventricular pressure (-dp/dt), and heart rates(HR) were recorded synchronously. Labeling enzyme-linked immunosorbent (ELISA) was used to measure the plasma BNP concentration. The hearts were removed, the actual left and right ventricular weight (LVW, RVW) were measured separately, and the relative weight of left and right ventricular (LV/BW,RV/BW) were calculated. Statistics analysis used one-way ANOVA by SPSS 14.0 statistical software.Results: (1)the impact of hemodynamics: Compared with the Sham group, AMI group points significantly abnormal in hemodynamic parameters at different times(P all> 0.05) ,such as SP, LVSP,±dp/dt decreased, LVEDP increased. Compared with the AMI group, EPO group 1 week SP, LVSP and + dp/dt increased to a certain extent, but the difference was not statistically significant (P all> 0.05), LVEDP decreased 32%, - dp/dt increased by 33% , the difference was statistically significant (P all <0.01). SP increased 20%, LVSP increased 31%, + dp/dt increased 27%, LVEDP decreased 96.9%, - dp/dt increased 38% three weeks after AMI, the difference was statistically significant (P all <0.01). (2) the impact of ventricular relative weight: compared with the Sham group, AMI group at different time points, LV/BW increased, the difference was statistically significant (P <0.01). With the AMI group, EPO group 1 week LV/BW decreased, but the difference was not statistically significant (P> 0.05), 3-week decline of 18%, the difference was statistically significant (P <0.01). (3) the impact of plasma BNP concentrations: compared with the Sham group, AMI group at different time points of plasma BNP concentration increased, the difference was statistically significant (P <0.01). With the AMI group, EPO group one week drop in plasma BNP concentration of 31%percent, decline in 3 weeks 47%, the difference was statistically significant (P all <0.01); (4) Comparison of three groups at different time points, there was no significant difference in DP and HR (P> 0.05).Conclusion: EPO intervention after AMI in rats can be (1) to improve the hemodynamic parameters, increased LVSP,±dp/dt, lower LVEDP. (2) reduce the plasma concentration of BNP. (3) reduce the LV/ BW. (4) RV/BW, DP and HR were no signifinant change. Results suggest that, EPO can improve left ventricular systolic and diastolic function, reduced left ventricular relative weight, with the inhibitory role of left ventricular remodeling.