The molecular mechanism of platelet lysate promotes transformation of non-union cells into osteoblasts

BACKGROUND: Platelet lysate (PL) had a remarkable therapeutic effect on bone repair related diseases, such as delayed fracture healing, femoral head necrosis and meniscal tear. In this study, we investigated the effect of PL on patients with nonunion, cartilage repair and osteonecrosis, and to evaluate the effect of PL on nonunion cells proliferation and the effect of PL on OPG/RANKL signaling pathway in nonunion cell of male rats. To reveal the molecular mechanism of PL for bone healing. METHODS: We used different concentrations of PL to treat nonunion cells, then detected cell proliferation and protein expression levels of osteoprotegerin (OPG), RANKL, osteopontin (OPN), osteocalcin (OCN) and alkaline phosphatase (ALP). RESULTS: The proliferation rate of nonunion cells treated by 5% PL, was significantly higher than that of the control group (P<0.05). Surprisingly, there were no significant difference among the proliferation rates of nonunion cells treated by 8% PL, 10% FBS and the control group (P>0.05). the results of western blot analysis and immunofluorescence analysis showed that PL improved the expression of OPG, OPN, OCN and ALP proteins in nonunion cells, but PL had no effect on the expression of nuclear factor-κB ligand (RANKL) protein. CONCLUSIONS: We found that PL had a remarkable therapeutic effect on bone repair related diseases; 5% PL significantly improved the proliferation rate of the nonunion cells; 10% PL had a significantly positive effect on improving the expression levels of osteogenic related genes.