Astragaloside IV alleviates hypoxia/reoxygenation-induced neonatal rat cardiomyocyte injury via the protein kinase a pathway

Da Wei Zhang, Zhi Ping Bian, Jin Dan Xu, Heng Fang Wu, Chun Rong Gu, Bin Zhou, Xiang Jian Chen, Di Yang

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Background: Astragaloside IV (As-IV) exerts beneficial effects on hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury, possibly through normalization of sarcoplasmic reticulum Ca2+ ATPase (SERCA2a) function. The exact mechanisms remain unknown. This study was designed to investigate the role of protein kinase A (PKA) in the protective effect of As-IV on SERCA2a function. Methods: Cultured cardiomyocytes from neonatal rats were exposed to 6 h of hypoxia followed by 3 h of reoxygenation (H/R) with or without As-IV treatment. Myocyte injury was determined by the creatine kinase (CK)-MB fraction in supernatant. Myocardial SERCA2a activity and PKA kinase activity were assessed. PKA subunit mRNA expression and Ser16 phosphorylated phospholamban (Ser16-PLN) protein expression were detected by real-time PCR and Western blot, respectively. Results: The administration of As-IV significantly decreased CK-MB release and restored SERCA2a activity in H/R cardiomyocytes. The mRNAs of PKA subunits, PKA-RIα, PKA-RIIα, PKA-RIIβ, PKA-Cα and PKA-Cβ, were downregulated in H/R cardiomyocytes. However, PKA-Cα mRNA expression was significantly increased after As-IV treatment. Meanwhile, there was a tendency to recovery of the H/R-induced PKA kinase activity decrease after As-IV treatment. The expression of Ser16-PLN protein, which is specifically phosphorylated by PKA, was upregulated in As-IV-treated H/R cardiomyocytes. Conclusions: These results suggest that the cardioprotection of As-IV may be through the upregulation of PKA and Ser16-PLN, thereby restoring SERCA2a function in H/R injury.

Original languageEnglish (US)
Pages (from-to)95-101
Number of pages7
JournalPharmacology
Volume90
Issue number1-2
DOIs
StatePublished - Aug 1 2012

Keywords

  • Astragaloside IV
  • Cardioprotection
  • Hypoxia/Reoxygenation
  • Phospholamban
  • Protein kinase A
  • Sarcoplasmic reticulum calcium ATPase

ASJC Scopus subject areas

  • Pharmacology

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