Stachydrine ameliorates hypoxia reoxygenation injury of cardiomyocyte via enhancing SIRT1-Nrf2 pathway

Background: Hypoxia/reoxygenation (H/R)-induced cardiomyocyte cell Apoptosis is critical in developing myocardial infarction. Stachydrine (STA), an active constituent of Leonurus heterophyllus sweet, could have a protective effect on myocardial H/R injury, which remains unexplored. Therefore, the study aimed to investigate the protective effects and mechanisms of STA on H/R injury of cardiomyocytes.

Methods: Rat cardiomyocyte H9c2 cells underwent H/R (hypoxia for 4 h and reoxygenation for 12 h). Cells were pretreated with STA (50 µM) 2 h before H/R. Cardiomyocyte injury was evaluated by CCK-8 assay and Lactate Dehydrogenase (LDH) release. Apoptosis was assessed by TUNEL staining and Caspase-3 activity. Oxidative stress was assessed by lipid oxidation product MDA and a ROS-scavenging Enzyme SOD in culture media. Western blot was performed to measure the protein expressions of SIRT1, Nrf2, and heme oxygenase-1 (HO-1).

Results: STA reversed the decrease in cell viability and increased LDH release in H9c2 cells with the H/R insult. STA significantly suppressed oxidative stress, reduced MDA content, and increased SOD activity in H9c2 cells exposed to H/R. STA reduced Apoptosis in H9c2 cells exposed to H/R, as evidenced by the reduced TUNEL positive cells and Caspase-3 activity. In addition, STA enhanced SIRT1, Nrf2, and HO-1 protein expression in H/R-stimulated H9c2 cells. SIRT1 and Nrf2 involved the protective effect of STA in H/R-exposed H9c2 cells, as the changes in cell viability and Caspase-3 activity by STA can be reversed by SIRT1 Inhibitor EX-527 or Nrf2 siRNA.

Conclusions: Our data speculated that STA protects H/R injury and inhibits oxidative stress and Apoptosis in cardiomyocytes by activation of the SIRT1-Nrf2 pathway.

Cardiomyocyte; Hypoxia/reoxygenation (H/R) injury; Nrf2; SIRT1; Stachydrine.