A Study On The Effect And Mechanism Of Carbamylated Erythropoietin-treated Rat With Chronic Heart Failure

【Objective】Observed the effect of carbamylated erythropoietin(carbamylated erythropoietin,CEPO)on chronic heart failure(chronicheart failure,CHF)in rats,and explored the expotential mechanism of CEPO-treated chronic heart failure.Those results can provide a theoretical basis for clinical treatment of CHF in the future.【Materials and methods】30 adult male SD rats were randomly divided into two groups: the Sham group(n=6)and the Opertation group(n=24).In the Sham group,the abdominal aorta was separated,but was not ligated.In the Operation group,the abdominal aorta was separated,and the model of choronic heart failure was well conducted by transverse abdominal aortic banding with a blunted 5-gauged needle.8 weeks after postsurgery,the surviving rats in Operation group were randomly distributed into three groups: the blank control group(n=6),the EPO group(n=7),the CEPO group(n=6).And the rats in the Sham group were refered to negative control group.In the EPO group,rats were injected intraperitoneally with EPO(3000U/kg).In the CEPO group,rats were treated by CEPO(50 ug/kg).And all rats in the Control and Sham groups,the same amount of 0.9% saline was used.The treatment was conducted three times one week for four weeks.At end of the treatment,we evaluated the alternation of cardiac structure and funtion by detecting end diastolic interventricular septal thickness and end systolic interventricular septal thickness(IVSd and IVSs),left ventricular posterior wall end-diastolic and end-systolic thickness(LVPWd and LVPWs)and left ventricular ejection fraction(EF%)using transthoracic echocardiography.After 12 hours fasting,all rats were sacrificed with overdose of chloral hydrate by intraperitoneal injection.The hearts were carefully removed from rats.And the changes of tissue pothology were observed by tissue section H&E staining.Tissue sections were measured by TUNEL methods.Then the apoptosis index(AI)was calculated.The protien expression of cleaved Caspase-3 was detected by western blot.Both of AI and cleaved Caspase-3 protein expression were used to evaluate cardiomyocytes apoptosis.The effect of drug-stimulated bone marrow hematopoiesis was assessed by the content of red blood cell and hemoglobin in blood sample.【Results】1.Four weeks after treatment,transthoracic echocardiography was conducted.And the results certified that compare with the Sham group,IVSs,LVSWs,IVSd and LVPWd were significantly increased in the control group.But the LVEF was markedly reduced.All of IVSs,LVSWs,IVSd and LVPWd were decreased in EPO and CEPO groups compared to Control group,while the LVEF was remarkably higher.2.Four weeks after treatment,H&E staining for tissue section was conducted.And the results showed that cardiomyocyte nuclei was stained blue,the staining was clare,the intercellular arrangement was neat and orderly,and the membrane was intact in the Sham grouop.But in the Control group,the size of cardiomyocytes was different,cell gap was widened and disorderly,interstitial fibrosis hyperplasia occurred,cell member ruptured,the staining of cell nucleus was imhonogeneous.Compared with Control group,the abnormal altenation of tissue pathology was improved in EPO and CEPO group.3.Four weeks after treatment,tissue section was subjected TUNEL stainig.And the results showed that in the Sham group,cell nuclei of cardiac tissue were stained with blue,the staining was clear and the distribution was Homogeneous.Some cell nuclei stained with brown were observed in some section,which were refered as apoptotic cells.Compare with Sham group,the number of apoptotic cells was significantly increased in Control group.While the number of apoptotic cells wasmarkedly reduced in EPO and CEOP groups,compare to Control group.4.Four weeks after treatment,the expression level of cleaved Caspase-3 in cardiac tissue was detected by western blot.And the results demonstrated that comopared with the Sham group,the protein expression of cleaved Caspase-3 was up-regulated in Control group.While the cleaved Caspase-3 expression was down-regulated in EPO and CEPO groups,coopare to control group.5.Four weeks after treatment,the blood sample was acquired.And the the content of red blood cell and hemoglobin was measured.The results indicated that compared with Sham group and Control group,there was no significant change in the content of erythrocyte and hemoglobin in CEPO group,but the EPO group was significantly higher than that in control group.【Conclusions】1.CEPO can improve the cardiac function in rat with CHF,and its effect was consistent with EPO,but less stimulated bone marrow hematopoiesis.2.The mechanism of CEPO improving cardiac function in rats with chronic heart failure may be related to inhibition of cardiomyocyte apoptosis.