Combined utilization of bisoprolol and glutathione attenuates ventricular remodeling of takotsubo cardiomyopathy in mice

Objective To investigate the therapeutic effect of combined utilization of bisoprolol and glutathione (GSH) for attenuating ventricular remodeling of Takotsubo cardiomyopathy (TTC) in mice. Methods C57BL/6J male mice with TTC (n=60) were randomly divided into five groups as: (1) saline control group (n=9), 0.5 ml saline intraperitoneal injection (i.p) once a day; (2) isoprenaline (ISO) control group (n=11), 50 mg/kg ISO i. p once a day; (3) ISO+ bisoprolol group (Biso group, n=12), 10 mg/kg bisoprolol intragastric administration(i.g) once a day; (4) ISO+ GSH group (GSH group, n=12), 250 mg/kg GSH i. g once a day; (5) ISO+ Biso+ GSH group (Biso+ GSH group, n=16). Echocardiographic, haemodynamic, morphopatholoical and molecular data were analyzed for each group 3 weeks after given different treatment. Results (1) ISO+ Biso+ GSH group had a more stable body weight than other groups with a significant difference (F=2.48, P<0.05). (2) Left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), interventricular septum (IVSD) and left ventricular posterior wall (LVPWD), fractional shortening(FS), ejection fraction (EF), end-systolic pressure(EDS), end-diastolic pressure(EDD), dp/dt max, and dp/dt min in ISO+ Biso+ GSH group were superior to other groups respectively (F=10.49, P<0.001; F=9.53, P<0.001; F=15.60, P<0.001; F=32.56, P<0.001; F=36.56, P<0.001; F=44.21, P<0.001; F=15.03, P<0.001; F=42.01, P<0.001; F=33.40, P<0.001). (3) Heart weight (HW)/body weight (BW) (mg/g), HW/tibial length (TL) (mg/mm) and lung weight (LW)/BW (mg/g) ratios in ISO+ Biso+ GSH group were better than other groups with the significant difference (F=16.51, P<0.001; F=36.57, P<0.001; F=15.50, P<0.001), wherease no statistical significance was found between ISO+ GSH and ISO+ Biso groups. In the follow-up experiment, the ISO+ Biso+ GSH group shows better myocardiac remodeling than other groups, that was confirmed by the stains of haematoxylin-eosin (HE), picrosirius red (PSR), for membranes with FITC-conjugated WGA (Wheat Germ Agglutinin, Invitrogen) and for nuclei with DAPI were used for reflecting the degree of cardiac hypertrophy and fibrosis, combined with the quantitative analysis of myocyte cross-sectional area and collagen volume fraction. The difference were statistical significant (0.47%±0.05% vs. 0.17%±0.01%, 1.64%±0.004%, 0.67%±0.08% and 0.65%±0.04%, all P<0.05). (4) The levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and beta myosin heavy chain (β-MHC), and connective tissue growth factor (CTGF), collagenase1a (Coll1α), and transforming growth factor-β1 (TGF-β1) were all down-regulated in ISO+ Biso+ GSH group. C-reactive protein 3 (CRP3) and tumor necrosis factor α (TNF-α) were also down-regulated and superoxide dismutase 1(SOD1) and SOD2 were all up-regulated markedly. Bax was down-regulated and B-cell lymphoma-2 (Bcl-2) up-regulated (P<0.05). Conclusions The ventricular remodeling of TTC could be improved markedly when combined using bisoprolol and GSH. Key words: Bisoprolol; Glutathione; Takotsubo cardiomyopathy; Ventricular remodeling