Abstract:Objective To investigate the effect of cyclic stretch on adhesion of vascular smooth muscle cells (VSMCs) with platelet-derived microparticles (PMPs), and the role of PMPs in VSMC autophagy. Methods Cyclic stretch with the magnitude of 5% (simulating physiological mechanical stretch) or 15% (simulating pathological mechanical stretch) was subjected to VSMCs in vitro by using FX-5000T cyclic stretch loading system, and the adhesion of PMPs in VSMCs was detected by using flow cytometry. Immunofluorescence was used to detect the expression of autophagy microtubule associated protein light chain 3 (LC3) after 24 h stimulation with PMPs. Western blotting was used to detect the expression of autophagy related protein (Atg) in VSMCs after 24 h stimulation by PMPs. Results Compared with 5% cyclic stretch, 15% cyclic stretch significantly increased the adhesion ability of VSMCs with PMPs. Immunofluorescence and Western blotting result revealed that PMPs stimulation significantly increased the expression of autophagy marker protein LC3 in VSMCs. Furthermore, the protein expressions of Atg5, Atg7 and Atg12 were all significantly increased in VSMCs stimulated with PMPs. Conclusions High cyclic stretch may enhance the autophagy of VSMCs by promoting the adhesion of PMPs, which will subsequently increase the expressions of Atg5, Atg7, Atg12 and LC3.