Phellinus merrillii extracts induce apoptosis of vascular smooth muscle cells via intrinsic and extrinsic pathways.

Restenosis frequently occurs after balloon angioplasty. Percutaneous coronary intervention (PCI)-induced artery damage is a significant part of triggering restenosis of the vascular smooth muscles (VSMC). This study aimed to study how ethanol extract of Phellinus merrillii (EPM) affected balloon injury-induced overgrowth of VSMC, indicating neointima formation. Firstly, our results demonstrated that EPM notably decreased VSMC viability. A fragmentation assay and Annexin V/Propidium Iodide apoptosis assay showed that higher doses of EPM significantly induced the apoptosis of VSMC after 24 h of exposure. Total protein extracted from VSMC treated with EPM in various time and concentration periods was then conducted in Western blotting analysis. Our data demonstrated that EPM substantially elevated the p53, p21, Fas, Bax, p-p38, and active caspase-3 protein expressions. The results indicated that EPM induces VSMC apoptosis via intrinsic and extrinsic pathways. Also, our results demonstrated that EPM effectively attenuated the balloon injury-induced neointima formation. In conclusion, the information offers a mechanism of EPM in inducing the VSMC apoptosis, thus as a potential interference for restenosis.