Platelet-rich plasma enhances anti-apoptotic and paracrine effects of bone marrow mesenchymal stem cells through the...

Previous studies have shown that bone marrow aspirate concentrate (BMAC) can promote tendon-bone interface healing in a rabbit chronic rotator cuff tear model, but its underlying mechanism of action has not been fully elucidated. We suspected that the synergistic effect of platelet-rich plasma (PRP) and bone marrow mesenchymal stem cells (BMSCs) in BMAC might improve the anti-apoptotic and paracrine effects of BMSCs. Here, we prepared rabbit PRP and BMSCs, and found that PRP not only attenuated hypoxic and serum-free medium (H/SF)-induced apoptosis of BMSCs but also increased the protein expression of Bcl2, which was reduced by H/SF, and decreased the protein expression of cleaved caspase 9, and cleaved caspase 3, which was elevated by H/SF, in BMSCs. PRP also promoted the expression of growth factors (PDGF, VEGF, TGF-β1, and IGF-1) in BMSCs. In a chronic rotator cuff tear rabbit model, the PRP + BMSC-treated group showed higher values of biomechanical properties than the BMSC-treated group. Furthermore, results also showed that PRP promoted the phosphorylation of Akt in BMSCs, and inhibition of the PI3K/Akt pathway not only increased the apoptosis of BMSCs cultured with PRP, but it also decreased the concentration of growth factors in culture medium of BMSCs. Collectively, our results indicate that PRP enhances the anti-apoptotic and paracrine effects of BMSCs, and this might be related to the activation of the PI3K/Akt pathway in BMSCs by PRP.