Abstract
Danhong injection (DHI) is used widely against cardiovascular disease in China. Recent studies have demonstrated its mitochondria-protection effect as being pivotal in treatment of myocardial ischemia/reperfusion (I/R) injury, but the underlying mechanism of action is incompletely understood. We aimed to identify the effect and mechanism of action of DHI on mitochondrial integrity and cardiomyocyte apoptosis after I/R. An I/R rat model was induced to detect the effect of DHI on myocardial repair by infarct size, apoptosis and oxidative stress. In vitro, H9C2 cells or H9C2 cells with nuclear factor erythroid 2-related factor 2 (Nrf2) knockdown were injured under hypoxia-reoxygenation (H/R). The effects of DHI on apoptosis, antioxidant capacity and mitochondrial integrity were evaluated by mitochondrial morphology, apoptosis rate, reactive oxygen species (ROS) generation, ATP levels, mitochondrial membrane potential, and oxygen consumption in H9C2 cells treated with H/R. The underlying mechanism of action of DHI in maintenance of mitochondrial integrity and anti-apoptosis was detected in H9C2 cells with or without Nrf2 knockdown. DHI treatment significantly decreased the infarct size, inhibited apoptosis and suppressed oxidative stress in the hearts of I/R rats. Also, DHI promoted cell survival by: an anti-apoptosis action; inhibiting ROS generation; maintaining mitochondrial morphology with increased mitochondrial length; alleviating mitochondrial dysfunction with a decreased mitochondrial membrane potential; increasing ATP levels and the oxygen-consumption rate. Moreover, the Keap1/Nrf2/JNK pathway was found to be involved in DHI reducing oxidative stress and maintaining mitochondrial integrity. We revealed a novel mechanism by which DHI protected H9C2 cells against H/R injury via the Keap1/Nrf2/JNK pathway and provided a mitochondrial protectant for the treatment of myocardial I/R injury.
Highlights
Persistent myocardial ischemia causes permanent damage to the myocardium, which is destroyed and replaced by fibrous scar tissue and subsequently develops into heart failure
The decreased apoptosis mediated by Danhong injection (DHI) was reversed when H9C2 cells were transfected with nuclear factor erythroid 2-related factor 2 (Nrf2) short hairpinRNA (Figures 8D,E). These findings suggested that JNK was downstream of Nrf2, and that Nrf2 might be required for DHI-mediated improvements in survival of H9C2 cells after H/R stimulation
The increased membrane potential (MMP) (Figures 9C,D), reduced mitochondrial permeability transition pore (mPTP) opening (Figures 9C,E), decreased expression of reactive oxygen species (ROS) (Figure 9F) and increased ATP production (Figure 9G) mediated by DHI were reversed when H9C2 cells were transfected with Nrf2 shRNA. These findings suggested that Nrf2 was required for DHImediated improvements in mitochondrial integrity after H/R stimulation
Summary
Persistent myocardial ischemia causes permanent damage to the myocardium, which is destroyed and replaced by fibrous scar tissue and subsequently develops into heart failure. Restoration of blood flow to the ischemic myocardium limits infarct size, improves cardiac function, reduces mortality, and has become first-line treatment of myocardial ischemia. Cardiomyocyte death is the main manifestation of myocardial IR injury, and is considered to be the main potential cause of ventricular remodeling and cardiac dysfunction (RabinovichNikitin et al, 2019). In general, it is accepted that mitochondrial dysfunction plays a key part in IR pathology and is the major cause of the injury and death of cardiomyocytes (Pell et al, 2016). Despite the development of promising mitochondria-targeting drugs, very few have been used successfully in the clinic. Betaland colleagues indicated that in the future advances in therapy for myocardial IR would come from improvement of the treatments already available rather than the discovery of new drugs (Ibáñez et al, 2015)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
