Roles ofβ-AR/PKA/CaMK Ⅱ signaling pathway in cardiomyocyte apoptosis induced by adriamycin in rats / 中国药理学通报

ABSTRACT

Aim Toresearchthemolecularmecha-nisms of adriamycin-induced cardiomyocyte apoptosis based on β-adrenoceptor signaling pathway during de-velopmentofheartfailure.Methods SeventymaleSD rats were assigned randomly into two groupsthe con-trol group(CON,n=30)and the ADR-induced cardio-toxicity group (ADR,n =40 ).ADR was administered intraperitoneally in five equal injections (each contai-ning 3 mg·kg-1 )over a period of two weeks,with a total cumulative dose of 15 mg · kg-1 body weight. Age-matched rats injected with saline were used as controls.The general condition of all rats was observed, and transthoracic echocardiography was performed im-mediately following the final ADR injection,and then every other week.Serum and myocardial tissue were harvested at W2,W4 and W6 separately.The serum contents of brain natriuretic peptide(BNP)and cardiac troponin-T(cTn-T)were analyzed by euzymelinked im-munosorbent assay (ELISA ).The pathological change and apoptosis were determined by HE,Masson and ter-minal deoxyribonucleotide transferase-mediated dUTP nick end labeling (TUNEL).The protein expressions ofβ1-AR,β2-AR,PKA and CaMK Ⅱ were detectedbyWesternblot.Results FollowingthefinalADRin-jection,cardiac systolic function and SV declined, which was accompanied by marked atrophy of the heart,low levels of cardiomyocyte fibrosis and apopto-sis,significantly increased serum BNP and cTn-T and decreased β1-AR,PKA and CaMK Ⅱ protein expres-sion.However,cardiac systolic function was improved with the extension of time but remained depressed as compared to CON group.The serum BNP and cTn-T concentration kept on rising.The gradual aggravation apoptosis and concomitant fibrosis in the ADR group heart were observed following ADR withdrawal.β1-AR protein expression was continuously down-regulated,β2-AR protein expression unchanged.Expression of PKA and CaMKⅡ proteins in hearts from ADR-injec-ted rats gradually increased.Conclusion β-AR/PKA/CaMKⅡ signaling pathway mediates cardiomyo-cyte apoptosis during the progress of ADR-induced car-diac dysfunction and pathological remodeling and apop-tosis.