Songling Xuemaikang Capsule inhibits isoproterenol-induced cardiac hypertrophy via CaMKIIδ and ERK1/2 pathways

Ethnopharmacological relevance: Cardiac hypertrophy is a key pathologic process in heart failure. Songling Xuemaikang Capsule (SXC), is a formulae of Chinese Medicine commonly used in China to treat hypertension and heart failure. However, its mechanism of effects on cardiac hypertrophy is still unclear. Aim of the study: The aims of the present study were to investigate the cardio-protection roles and detailed mechanisms of SXC on cardiac hypertrophy in vivo and in vitro. Materials and methods: A rat model of cardiac hypertrophy was constructed by isoproterenol (ISO) intraperitoneal injection (i.p), 10 mg/kg/day for 3 days, and 4 groups were compared: CON (n = 8), ISO (n = 8), MET (metoprolol, positive drug treatment, n = 7), and SXC (SXC treatment, n = 6). Cardiac structure and function were evaluated with echocardiography in vivo. Dose-dependent curve was obtained with SXC different concentrations. In addition, H9C2 rat cardiomyocytes were cultured in vitro and the phosphorylation of ERK1/2, p38, JNK, AKT, and protein expression of CaN, CaMKIIδ, GATA4 were detected with Western blot test. Results: The results showed that SXC reduced diastolic thickness of left ventricular posterior wall, while did not change ejection fraction and fraction shortening significantly (P > 0.05). SXC inhibit ISO-induced cardiac hypertrophy dose-dependently with 50% inhibiting concentration (IC50) is 0.504 g/kg/day. Moreover, SXC inhibited the protein expression of CaMKIIδ, and the phosphorylation of ERK1/2, so inhibiting protein expression of GATA4 in nucleus, and brain natriuretic peptide in serum (P < 0.001). Conclusion: The mechanism of SXC in the treatment of heart diseases involves SXC dose-dependently inhibited the ISO-induced cardiac hypertrophy via inhibiting CaMKIIδ and ERK1/2/GATA4 signaling pathway.