Tanshinone ⅡA alleviates endothelial-to-mesenchymal transition by regulating the TGF-β/Smad pathway

Intimal hyperplasia is a pathological process that occurs due to vascular endothelial injury following PCI. TGF-β/Smad signaling-mediated endothelial-mesenchymal transition (EndMT) is particularly important in the development of intimal hyperplasia. Tanshinone ⅡA (TanⅡA), which is extracted from Salvia miltiorrhiza (also known as Danshen), has been shown to be safe and effective in reducing inflammatory factors and enhancing endothelial function in patients after PCI. To investigate the mechanism of TanⅡA in alleviating TGF-β1-induced EndMT, the EndMT model was developed by treating human umbilical vein endothelial cells (HUVECs) with TGF-β1. The effects of different concentrations of TanⅡA on HUVECs cell viability were assessed using WST-1 assay. Cell morphology was examined using fluorescent staining. A wound-healing assay was performed to evaluate the migratory ability of the cells. The expression of specific proteins, including the endothelial marker VE-Cadherin, and interstitial cell markers such as α-SMA, FSP-1, Smad2/3 (along with their phosphorylated forms), as well as the transcription factors Slug and Snail, was analyzed using PCR and Western blotting. The results of the WST-1 experiment showed that TanⅡA concentration of 20 μmol·L^-1 significantly inhibited cell proliferation. Migration experiments showed that TGF-β significantly enhanced cell migration abilities, while TanⅡA was able to reverse this effect. Western blotting analysis revealed a notable decrease in the expression level of VE-Cadherin protein, alongside a significant increase in the levels of α-SMA, FSP-1, and COL1 proteins following TGF-β induction. Co-treatment with TanⅡA and TGF-β1 resulted in a notable reduction in the levels of Smad2 and Smad3, as well as their phosphorylation, compared to the model group. These findings suggest that TanⅡA can inhibit TGF-β-induced EndMT by blocking the activation of the Smad signaling pathway.