Salvianolic Acid B Inhibits the Proliferation and Extracellular Matrix Metabolism of Cardiac Fibroblasts through the MiRNA-296-5p/TGF-β1/Smads Axis

Abstract

Objectives: To examine the role of Salvianolic acid B (Sal-B) in cardiac fibroblasts (CFs) proliferation and extracellular matrix metabolism. Methods: An in vitro model of myocardial fibrosis was constructed by treating primary CFs with isoprenaline (ISO) for 48 h. CFs were extracted from neonatal male Sprague-Dawley rats. CFs were allocated to one of the following groups: Control group (untreated), model group (ISO-treated CFs) and Sal-B groups (pre-treated with 50, 100, and 200 µM of Sal-B for 24 h). Immunofluorescence staining was conducted to examine Galectin-3 expression. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to determine miR-296-5p expression in CFs. Western blotting and qRT-PCR were employed to respectively detect the protein and mRNA expression of Matrix Metallopeptidase 2 (MMP2), MMP9, transforming growth factor-β 1 (TGF-β1), Collagen I (Col I), Collagen III (Col III), small mother against decapentaplegic (SMAD) family member 3 (Smad3), and Smad7. Ultimately, dual-luciferase reporter assay was applied to explore the targeting relationship between TGF-β1 and miR-296-5p. Results: Sal-B treatment weakened cell viability in the Sal-B group compared to the model group (p < 0.05). Sal-B notably down-regulated MMP2, MMP9, Col I, and Col III mRNA expression in the Sal-B group compared to the model group. Meanwhile, Sal-B treatment reversed the increasing TGF-β1 and Smad3 protein and mRNA expression induced by ISO. The Sal-B group displayed a rise in miR-296-5p expression compared to the model group. Dual-luciferase reporter assay demonstrated that TGF-β1 was the downstream gene of miR-296-5p. Conclusions: Sal-B reduced CFs proliferation and the buildup of extracellular matrix through the miR-296-5p/TGF-β1/Smads axis.