Biotechnological Elucidation of Xinyin Tablet's Mechanism: SIRT1 Activation Attenuates Cardiac Fibrosis Via Suppressing Endothelial-to-Mesenchymal Transition.

Xinyin tablet (XYT), a traditional Chinese medicine consisting of Ginseng, Ophiopogon, Astragalus, Ilex pubescens, Motherwort, and other medicines, is clinically used to manage chronic heart failure (HF), yet its molecular mechanisms remain underexplored. This study integrates biotechnological approaches to investigate how XYT mitigates cardiac fibrosis by targeting the SIRT1-mediated TGF-β/Smad signaling pathway. Transverse aortic constriction (TAC)-induced HF mice and TGF-β1-stimulated myocardial microvascular endothelial cells (MMECs) were employed. Echocardiography, histopathology, and molecular assays (qRT-PCR, Western blotting, siRNA transfection) were utilized to assess cardiac function, fibrosis, and signaling pathways. XYT treatment significantly improved cardiac function (↑LVEF, LVFS; ↓LVIDs, LVIDd) and reduced collagen I/III deposition in TAC mice. Mechanistically, XYT upregulated SIRT1 expression while suppressing EndMT markers (↓α-SMA, ↑VE-cadherin) and TGF-β/Smad signaling (↓TGF-βR1, p-Smad2/3). Crucially, SIRT1 knockdown in MMECs abolished XYT's inhibitory effects on EndMT and TGF-β/Smad activation, confirming SIRT1's pivotal role. These findings highlight XYT's biotechnological relevance by linking SIRT1 activation to EndMT inhibition, offering a novel therapeutic strategy for cardiac fibrosis. This study underscores the potential of integrating traditional medicine with molecular biotechnology to develop targeted therapies for cardiovascular diseases.