Background: Sepsis, a life-threatening systemic syndrome related to inflammatory response, usually accompanied by major organ dysfunctions. The aim of the present study was to elucidate the role by which Shengmai injection (SMI) acts to septic cardiomyopathy.
Methods: Initially, the induced mice with septic cardiomyopathy were treated with SMI or normal saline (NS) with oe-caspase-3, and HL-1 cells were treated with oe-Beclin-1 and oe-caspase-3 and then cultured with lipopolysaccharide (LPS). Subsequently, we measured the cardiac troponin I (cTnI) level, and expression of mitochondrial autophagy protein (parkin and pink1) and myocardial cell autophagy-related proteins (LC3-II and LC3-I). Additionally, we identified the cleavage of Beclin-1 by caspase-3 and detected the changes of mitochondrial membrane potential, level of reactive oxygen species (ROS), and apoptosis of myocardial cells in myocardial tissues of mice.
Results: It has been demonstrated that SMI contributed to the increase of myocardial mitochondrial autophagy, reduction of cTnI level, and elevation of mitochondrial membrane potential in septic cardiomyopathy mice. Both in vitro and in vivo experiments showed that caspase-3 promoted cleavage of Beclin-1 and release of ROS, whereas repressed lipopolysaccharide (LPS)-induced mitochondrial autophagy. Furthermore, the facilitation of myocardial mitochondrial autophagy and protection of myocardial mitochondria by SMI through inhibition of cleavage Beclin-1 by caspase-3 in septic cardiomyopathy mice were also proved by in vivo experiments.
Conclusion: Taken together, SMI could protect myocardial mitochondria by promoting myocardial mitochondrial autophagy in septic cardiomyopathy via inhibition of cleavage of Beclin-1 by caspase-3. Our study demonstrates that SMI could represent a novel target for treatment of septic cardiomyopathy.
Keywords: Beclin-1; Caspase3; Cleavage; Mitochondrial autophagy; Septic cardiomyopathy; Shengmai injection.