Sodium Danshensu alleviates oxidative stress-induced endothelial apoptosis and senescence by modulating the SIRT1/p53...

Salvia miltiorrhiza Bunge (Danshen) is a renowned traditional Chinese medicine widely used to promote blood circulation, remove blood stasis, and treat cardiovascular disorders. Sodium danshensu (SDSS), the stabilized sodium salt of Danshen's major water-soluble bioactive constituent, has been well-documented to possess antioxidant, anti-inflammatory, and cardiovascular protective properties, underpinning its considerable clinical potential. Nevertheless, whether SDSS protects against oxidative stress-induced cellular injury and the associated vascular damage remains insufficiently defined.

This study aimed to investigate whether SDSS alleviates oxidative stress-induced endothelial dysfunction and vascular injury and to clarify the involvement of the SIRT1/p53 signaling pathway.

An oxidative stress-related vascular injury model was established in C57BL/6J mice by intraperitoneal injection of tert-butyl hydroperoxide (t-BHP), and an in vitro model of oxidative stress-induced cellular injury was induced by hydrogen peroxide (H₂O₂) in human umbilical vein endothelial cells (HUVECs). Aortic structural changes and senescence marker expression were assessed by Masson's trichrome staining and Western blotting, respectively. Cellular senescence, proliferation, and migration were evaluated using SA-β-Gal staining, EdU incorporation, and wound healing assay, respectively. Oxidative stress was assessed by measuring intracellular reactive oxygen species (ROS) levels, superoxide dismutase (SOD) activity, and the glutathione (GSH/GSSG) ratio. Mitochondrial function was assessed by measuring mitochondrial membrane potential (MMP), ATP content, mitochondrial morphology (Mito-Tracker staining), and mitophagy (LC3/TOMM20 co-localization). Apoptosis was measured by flow cytometry. The interaction between SDSS and SIRT1 was investigated using molecular docking, molecular dynamics (MD) simulations, cellular thermal shift assay (CETSA), and drug affinity responsive target stability (DARTS) assay. The involvement of the SIRT1/p53 pathway was further examined using SIRT1 siRNA knockdown, the SIRT1 inhibitor EX527, and the SIRT1 agonist SRT1720.

In t-BHP-induced mice, SDSS attenuated aortic collagen deposition and p53/p21 expression. In H₂O₂-exposed HUVECs, SDSS alleviated cellular senescence-like changes, restored proliferation and migration, reduced ROS accumulation, preserved MMP and ATP levels, maintained mitochondrial morphology, enhanced LC3B/TOMM20 co-localization, and attenuated apoptosis, as evidenced by reduced early apoptotic rate, decreased BAX, and increased Bcl-2 expression. Molecular docking combined with MD simulations provided computational support for a potential stable interaction between SDSS and SIRT1. CETSA and DARTS assays further supported an interaction between SDSS and SIRT1 and indicated that SDSS may stabilize SIRT1 protein. SDSS increased SIRT1 expression and promoted p53 deacetylation. The protective effects of SDSS were comparable to those of the SIRT1 agonist SRT1720, whereas SIRT1 siRNA or EX527 treatment markedly weakened the protective effects of SDSS in vitro and in vivo, supporting a role for the SIRT1/p53 axis in mediating the protective response.

SDSS alleviates oxidative stress-induced vascular injury and endothelial dysfunction, and that these protective effects are associated with activation of the SIRT1/p53 pathway. These results offer preliminary correlative evidence supporting the traditional use of Danshen in cardiovascular protection, and suggest that SDSS warrants further investigation as a candidate for oxidative stress-associated vascular dysfunction.