Panax quinquefolium saponin Optimizes Energy Homeostasis by Modulating AMPK-Activated Metabolic Pathways in Hypoxia-Reperfusion Induced Cardiomyocytes

Objective To investigate the effects and underlying mechanisms of Panax quinquefolium saponin (PQS) on energy deficiency in hypoxia-reperfusion (H/R) induced cardiomyocytes. Methods The H/R injury involved hypoxia for 3 h and then reperfusion for 2 h. Cardiomyocytes recruited from neonatal rat ventricular myocytes (NRVMs) were randomly divided into control, H/R, H/R+compound C (C.C), H/R+PQS, and H/R+C. C+PQS groups. BrdU assay, lactase dehydrogenase (LDH) leakage and early apoptosis rate were evaluated to assess cell damages. Contents of high energy phosphate compounds were conducted to detect the energy production. Protein expression levels of adenosine monophosphate-activated protein kinase a (AMPK alpha), glucose transporter 4 (GLUT4), phosphate fructose kinase 2 (PFK2), fatty acid translocase/cluster of differentiation 36 (FAT/CD36), and acetyl CoA carboxylase 2 (ACC2) in the regulatory pathways were measured by Western blotting. Immunofluorescence staining of GLUT4 and FAT/CD36 was used to observe the mobilization of metabolic transporters. Results PQS (50 mg/L) pretreatment significantly alleviated H/R-induced inhibition of NRVMs viability, up-regulation of LDH leakage, acceleration of early apoptosis, and reduction of energy production (P<0.05). Compared with the H/R group, up-regulated expression of AMPK alpha, GLUT4, PFK2, FAT/CD36 and ACC2 were observed, and more GLUT4 and FAT/CD36 expressions were detected on the membrane in the H/R+PQS group (P<0.05). These effects of PQS on H/R-induced NRVMs were eliminated in the H/R+C.C+PQS group (P<0.05). Conclusion PQS has prominent advantages in protecting NRVMs from H/R-induced cell damages and energy metabolic disorders, by activation of AMPK alpha-mediated GLUT4-PFK2 and FAT/CD36-ACC2 pathways.

Automated summary

This study demonstrates that Panax quinquefolium saponin (PQS) can protect cardiomyocytes from hypoxia-reperfusion (H/R) induced damages and energy deficiency by activating AMPK alpha-mediated GLUT4-PFK2 and FAT/CD36-ACC2 pathways.