Cardiac ischemia-reperfusion (I/R) injury remains a challenge for clinicians, which initiates with energy metabolism disorder. The present study was designed to investigate the protective effect of notoginsenoside R1 (NR1) on I/R-induced cardiac injury and underlying mechanism. Male Sprague-Dawley rats were subjected to 30-min occlusion of the left coronary anterior descending artery followed by reperfusion with or without NR1 pretreatment (5 mg·kg(-1)·h(-1)). In vitro, H9c2 cells were cultured under oxygen and glucose deprivation/reoxygenation conditions after NR1 (0.1 mM), Rho kinase (ROCK) inhibitor Y-27632 (10 μM), or RhoA/ROCK activator U-46619 (10 nM) administration. Myocardial infarct size, myocardial histology, and cardiac function were evaluated. Myofibril and mitochondria morphology were observed by transmission electron microscopy. F-actin and apoptosis were determined by immunofluorescence and TUNEL staining. ATP and AMP content were assessed by ELISA. Phosphorylated-AMP-activated protein kinase, ATP synthase subunits, apoptosis-related molecules, and the level and activity of ROCK were determined by Western blot analysis. We found that NR1 pretreatment ameliorated myocardial infarction, histological injury, and cardiac function induced by I/R. Furthermore, similar to the effect of Y-27632, NR1 improved H9c2 cell viability, maintained actin skeleton and mitochondria morphology, and attenuated apoptosis induced by oxygen and glucose deprivation/reoxygenation. Importantly, NR1 prevented energy abnormity, inhibited the expression and activation of ROCK, and restored the expression of the mitochondrial ATP synthase δ-subunit both in vivo and in vitro, whereas U-46619 suppressed the effect of NR1. These results prove NR1 as an agent able to prevent I/R-induced energy metabolism disorder via inhibiting ROCK and enhancing mitochondrial ATP synthase δ-subunits, which at least partially contributes to its protection against cardiac I/R injury.

As a major ingredient of Radix ginseng, ginsenoside Rg1 (Rg1) has been increasingly recognized to benefit the heart condition, however, the rationale behind the role is not fully understood. In vitro study in H9c2 cardiomyocytes has shown the potential of Rg1 to increase ATP content in the cells. We thus speculated that the protective effect of Rg1 on heart ischemia and reperfusion (I/R) injury implicates energy metabolism regulation. The present study was designed to verify this speculation. Male Sprague-Dawley rats were subjected to 30 min of occlusion of left coronary anterior descending artery followed by reperfusion for 90 min. Rg1 (5 mg/kg/h) was continuously administrated intravenously 30 min before occlusion until the end of reperfusion. Myocradial blood flow and heart function were monitored over the period of I/R. Myocardial infarct size, structure and apoptosis, energy metabolism, and change in RhoA signaling pathway were evaluated 90 min after reperfusion. Binding of Rg1 to RhoA was assessed using Surface Plasmon Resonance (SPR). Rg1 prevented I/R-elicited insults in myocardium, including myocardial infarction and apoptosis, decreased myocardial blood flow (MBF) and heart function, and alteration in myocardium structure. Rg1 restored the production of ATP in myocardium after I/R. Rg1 was able to bind to RhoA and down-regulate the activity of RhoA signaling pathway. These results indicated that Rg1 had protective potential against I/R-induced myocardial injury, which may be related to inhibiting myocardial apoptosis and modulating energy metabolism through binding to RhoA.

Cardiac ischemia and reperfusion (I/R) injury remains a challenge for clinicians. Ginsenoside Rb1 (Rb1) has been reported to have the ability to attenuate I/R injury, but its effect on energy metabolism during cardiac I/R and the underlying mechanism remain unknown. In this study, we detected the effect of Rb1 on rat myocardial blood flow, myocardial infarct size, cardiac function, velocity of venule red blood cell, myocardial structure and apoptosis, energy metabolism and change in RhoA signaling pathway during cardiac I/R injury. In addition, the binding affinity of RhoA to Rb1 was detected using surface plasmon resonance (SPR). Results showed that Rb1 treatment at 5 mg/kg/h protected all the cardiac injuries induced by I/R, including damaged myocardial structure, decrease in myocardial blood flow, impaired heart function and microcirculation, cardiomyocyte apoptosis, myocardial infarction and release of myocardial cTnI. Rb1 also inhibited the activation of RhoA signaling pathway and restored the production of ATP during cardiac I/R. Moreover, SPR assay showed that Rb1 was able to bind to RhoA in a dose-dependent manner. These results indicate that Rb1 may prevent I/R-induced cardiac injury by regulation of RhoA signaling pathway, and may serve as a potential regime to improve percutaneous coronary intervention outcome.