Changes Of Myocardial Extracellular Matrix And Cathepsin D In Rats With Adriamycin-induced Heart Failure And Pharmacological Interventions

ObjectiveTo investigate the molecular mechanism of myocardial extracellular matrix (ECM)remodeling in rats with adriamycin-induced heart failure. To explore the role of cathepsin D(CatD) and study the protective effects of carvedilol and enalapril on cardiac injury.MethodsForty-four male SD Rats, weighed 230~270 g, were randomly divided into four groups: control group, n=8; adriamycin group, n=12; adriamycin+carvedilol group, n=12 ; adriamycin+enalapril group, n=12. The control group have received peritoneal injection with normal sodium once a week ,for six weeks. Adriamycin was given to the second to fourth groups with the dosage per 3mg/kg diluted to 2mg/ml with normal sodium once a week,all for six times.At the meantime the third group of rats received carvedilol 10mg?kg-1?d-1 intragastric administration and the fourth group of rats received enalapril 10mg?kg-1?d-1 intragastric administration.In the course of experiment ,observing the general state of health of the rats regularly such as the mental state,action,collar pattern,foodintake,weight and ascite. After 6 weeks,intervention,all rats were sacrificed after hemodynamics surveyed and echocardiography performed. Morphological characteristics were measured with HE, Sirus-red. Collagen volume fraction (CVF) was assessed with compute-assisted image analysis system. Immunohistochemistry staining labled fibronectin(FN) ,laminin(LN) and CatD with corresponding antibodies;Apoptotic cardiomyocytes were detected by in situ end labeling technique (TUNEL);The transcriptional level of CatD was evaluated by reverse transcription polymerase chain reaction(RT-PCR).Results1. Compared with the control group,hemodynamic parameters in the adriamycin group were deteriorated(P<0.05).Compared with the adriamycin group, pressure maximal rate of rise (+dp/dtmax) and pressure maximal rate of fall (-dp/dtmax) were increased , left ventricular end diastolic pressure (LVEDP) was decreased and left ventricular systolic pressure (LVSP) was increased in the carvedilol and enalapril groups (P <0.05).2. Compared with the control group,left ventricular diastolic dimension (LVDd) and left ventricular systolic dimension (LVDs) were significantly increased,left ventricular ejection fraction(EF) and fractional shortening(Fs) were significantly decreased in the adriamycin group(P<0.01).Carvedilol and enalapril improved them significantly.3. The pathological slices showed myocardial cell vacuolar denaturation, colliquative myocytolysis,myocardial fiber rupture and interstitial edema in the adriamycin group.A significant reduction in cardiac muscle cell lesions was detected when carvedilol or enalapril was given.4. Compared with the adriamycin group ,CVF of left ventricle was significantly decreased in the carvedilol and enalapril groups.5. The integrated optical density(IOD)of FN,LN and CatD in the left ventricle of the adriamycin group were remarkably higher than the control group(P <0.01). Compared with the adriamycin group,FN and LN were reduced in the carvedilol and enalapril groups.6. As compared with the control group, ADR group had significantly higher index of apoptotic cardiomyocytes.The number of apoptotic cardiomyocytes in the carvedilol and enalapril groups was less than that in ADR group (P < 0.05).7. The average optical of myocardial cathepsin D in the adriamycin group was notably higher than the control group. The amount of the expression of CatD was decreased in carvedilol group compared with the adriamycin group. The transcriptional level of CatD in the adriamycin group was much higher than the control group(P<0.01). The mRNA level of CatD in the carvedilol group was lower than the adriamycin group(P <0.05).Conclusions1. Model of chronic heart failure can be successfully established by intraperitoneal injection of ADR in rats,hemodynamic dysfunction and cardiac remodeling occurred in all rats with adriamycin-induced heart failure.2. The up-regulation of CatD in CHF was correlated with cardiomyocyte apoptosis and ECM remodeling.3. Carvedilol and enalapril could suppress cardiomyocyte apoptosis, mitigate cardiac remodeling and improve cardiac function.carvedilol could inhibit cardiomyocyte apoptosis via reducing the expression of CatD in myocardial tissue.