Measuring The Contribution Of Recombinant Human Erythropoietin To Contractile Function And Calcium Transient In Ischemia/Reperfusion(I/R)Cardiac Myocyte By Video-Based Motion Edge-Detection System At The Equal Pace

AIM: The protective effect of recombinant human erythropoietin(rHuEPO) on isolated myocardial contraction was investigated in. schemia/reperfusion (I/R) model METHODS: 1,pretreatment: Sixty male adult W istar rats were randomly divided into 3 groups:control group,I/R group,and I/R+ rHuEPO group.There were 20 rats in each group.The rats in rHuEPO group accepted peritoneal injection of 5000U/kg rHuEPO,and the other rats accepted the peritoneal injection of the same volume of saline.24h after the injection,isolated hearts studied by Langendorff model were subjected to perfusion for 30min,ischemia for 90 min and reperfusion for 60 min. Ventricular myocytes were enzymatically isolated from adult SD rats. Contribution of rHuEPO to contractile function and intracellular calcium transient in isolated I/R ventricular myocytes was assessd by Video-based motion edge-detection system. 2,aftertreatment : Sixty male adult W istar rats were randomly divided into 3 groups:control group,I/R group,and I/R+ rHuEPO group.There were 20 rats in each group.Ventricular myocytes were enzymatically isolated from adult SD rats. Chemical anoxic solution including sodium cyamide/sodium lactate was used to simulate myocardial ischemia. After 15 min, myocytes were reperfused with Tyrode's solution with or without rHuEPO for 30min. Contribution of rHuEPO to contractile function and intracellular calcium transient in isolated I/R ventricular myocytes was assessd by Video-based motion edge-detection system. RESULTS: 1,pretreatment with rHuEPO increased markedly peak twitch amplitude,maximal velocity of shortening,maximal velocity of relengthening of myocytes shorterning and fluorescence ratio Ca2+,and decreased markedly time to peak Ca2+,time to 50%diastolic Ca2+ compared with those in cells reperfused with vehicle (n = 20, P <0.05). 2,Reperfusion with rHuEPO increased markedly the amplitude and velocity of myocytes shorterning and calcium transient compared with those in cells reperfused with vehicle. Reperfusion with rHuEPO increased markedly peak twitch amplitude,maximal velocity of shortening,maximal velocity of relengthening of myocytes shorterning and fluorescence ratio Ca2+,and decreased time to peak Ca2+,time to 50%diastolic Ca2+ compared with those in cells reperfused with vehicle (n=20, P<0.05). CONCLUSION: Pretreatment and aftertreatment with rHuEPO during reperfusion facilitates the recovery of contractile function and calcium transient in simulated I/R cardiomyocytes.