Protocatechuic acid inhibits high shear stress-induced platelet adhesion and aggregation through the PI3K/Akt signaling pathway

High shear stress in stenotic arteries triggers platelet activation and aggregation, contributing to atherosclerosis and thrombus formation. Protocatechuic acid (PCA), a polyphenol metabolite, has been reported to inhibit shear-induced platelet aggregation (SIPA), but its precise mechanism remains unclear. We aimed to elucidate the mechanism by which PCA inhibits SIPA via the PI3K/Akt signaling pathway. A stenotic microfluidic chip model was used to simulate pathological high shear conditions (10,000 s −1 ). Platelet aggregation and activation were assessed, and the impact of PCA (51.91 μmol/L) on SIPA was evaluated. Flow cytometry was used to quantify platelet surface markers (using P-selectin and PAC-1 as indicators). Platelet morphology was examined via scanning electron microscopy. Platelet aggregation status was observed through electron microscopy. Western blotting was performed to assess PI3K/Akt signaling pathway proteins. PCA inhibited SIPA across the studied concentration range. At 51.91 μmol/L, PCA significantly reduced platelet adhesion and aggregation. Flow cytometry results indicated that PCA significantly inhibited the expression of the platelet activation marker CD62P. Western blot analysis revealed that PCA markedly inhibited PI3K expression and Akt phosphorylation induced by high shear stress. Co-treatment with the PI3K inhibitor TGX221 further enhanced PCA’s inhibitory effect on Akt phosphorylation. PCA suppresses platelet activation and aggregation under high shear stress, likely by inhibiting the PI3K/Akt signaling pathway, highlighting its potential as an antiplatelet agent.