Astragaloside IV ameliorates sepsis-induced myocardial dysfunction by regulating NOX4/JNK/BAX pathway

Sepsis can induce multiple organ dysfunction, and sepsis-induced myocardial dysfunction (SIMD) is relatively common. The current dilemma might ascribe partly to SIMD's lack of unified molecular mechanisms. Our study aims to assess the function of Astragaloside IV (ASI) in cecal ligation and puncture (CLP)-induced cardiac dysfunction and explore its underlying mechanisms.

In vivo, ASI (30 mg/kg/day), NADPH oxidase 4 (NOX4) inhibitor 4-hydroxy-3-methoxyacetophenone (APO, 30 mg/kg/day), reactive oxygen species (ROS) inhibitor N-Acetylcysteine (NAC, 150 mg/kg/day) and c-Jun NH2-terminal kinase (JNK) inhibitor (SP600125, 15 mg/kg/day) were severally administered to Sprague Dawley rats following the CLP surgery. The cardiac function, cardiac enzyme markers, proinflammatory cytokine, and cell apoptosis-associated proteins were detected. In vitro, cardiomyocyte H9C2 cells were treated with lipopolysaccharide (LPS, 40 μg/ml) after the presence of ASI (100 μmol/ml), SP600125 (10 μmol/ml), APO (10 μmol/ml). A series of experiments verified the relationship among NOX4, JNK, and BAX.

The results indicated that CLP-induced sepsis increased the secretion of creatine kinase isoenzymes (CKMB), brain natriuretic peptide (BNP), cardiac troponin T (c-TnI), interleukin-1β (IL-1β) and interleukin-18 (IL-18), as well as the protein expression of NOX4 and Caspase-3 in vivo. LPS increased the protein level of NOX4 and Caspase-3, upregulated the rate of p-JNK/JNK, and downregulated the rate of Bcl2/BAX in vitro. ASI can reverse these changes in vivo and has a synergistic effect with APO and SP600125 in vitro.

This study suggested that ASI may ameliorate SIMD, through regulating NOX4/JNK/BAX signaling pathway, which may be a feasible therapeutic strategy.