The protective effects of different compatibility proportions of the couplet medicines for Astragali Radix and Radix on myocardial infarction injury.

Astragali Radix (AR) and Radix (ASR) combinations are used to treat cardiovascular disorders. This study investigates the protective effects of different compatibility proportions of AR and ASR on cardiac dysfunction in a C57BL/6 mouse model of myocardial infarction (MI). MI mice were induced by ligation of the left coronary artery and divided into six groups: sham, vehicle, 10 mg/kg/d simvastatin and combinations of AR and ASR at different ratios, including 1:1 (AR 2.5 g/kg + ASR 2.5 g/kg), 3:1 (AR 3.75 g/kg + ASR 1.25 g/kg) and 5:1 (AR 4.17 g/kg + ASR 0.83 g/kg). Both AR-ASR combinations and simvastatin were dissolved in saline solution and given daily by gavage. The left ventricle function, infarct size, heart tissue injury, apoptosis of cardiomyocytes, leukocyte infiltrates, capillary density and expression of cleaved caspase-3, cleaved caspase-9, Bcl-2, Bax, Bad, IL-1β, IL-6, VEGF, p-Akt and p-eNOS were analysed. Different combinations of AR and ASR improve cardiac function and reduce infarct size (61.15% vs. 39.3%, 42.65% and 45.5%) and tissue injury through different mechanisms. When AR was combined with ASR at ratio of 1:1, the inflammation and cardiomyocyte apoptosis were suppressed ( < 0.05,  < 0.01). The combination ratio of 3:1 exerted effect in promoting angiogensis ( < 0.05). In the combination of AR and ASR at 5:1 ratio, angiogenesis was significantly improved ( < 0.01) and the apoptosis was inhibited ( < 0.05). Our results reflect the regulation of multiple targets and links in herb pairs and provide an important basis for the use of AR and ASR combinations in the treatment of MI.