Regenerative medicine for bone tissue mainly depends on efficient recruitment of endogenous or transplanted stem cells to guide bone regeneration. Platelet-derived growth factor (PDGF) is a functional factor that has been widely used in tissue regeneration and repair. However, the short half-life of PDGF limits its efficacy, and the mechanism by which PDGF regulates stem cell-based bone regeneration still needs to be elucidated. In this study, we established genetically modified PDGF-B-overexpressing bone marrow stromal cells (BMSCs) using a lentiviral vector and then explored the mechanism by which PDGF-BB regulates BMSC-based vascularized bone regeneration. Our results demonstrated that PDGF-BB increased osteogenic differentiation but inhibited adipogenic differentiation of BMSCs via the extracellular signal-related kinase 1/2 (ERK1/2) signaling pathway. In addition, secreted PDGF-BB significantly enhanced human umbilical vein endothelial cell (HUVEC) migration and angiogenesis via the phosphatidylinositol 3 kinase (PI3K)/AKT and ERK1/2 signaling pathways. We evaluated the effect of PDGF-B-modified BMSCs on bone regeneration using a critical-sized rat calvarial defect model. Radiography, micro-CT, and histological analyses revealed that PDGF-BB overexpression improved BMSC-mediated angiogenesis and osteogenesis during bone regeneration. These results suggest that PDGF-BB facilitates BMSC-based bone regeneration by enhancing the osteogenic and angiogenic abilities of BMSCs.

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A simple high-performance liquid chromatographic (HPLC) assay using the internal standard method is developed for the simultaneous determination of eight polyphenols. The analyzed compounds isolated from the leaves of Crataegus pinnatifida Bge. var. major include chlorogenic acid, vitexin-4"-O-glucoside, vitexin-2"-O-rhamnoside, vitexin, rutin, hyperoside, isoquercitrin, and quercetin. HPLC analysis is performed on a Diamonsil C18 analytical column (150 x 4.6 mm, i.d., 5-microm) using solvent (A) acetonitrile-tetrahydrofuran (95:5, v/v) and (B) 1% aqueous phosphoric acid as the mobile phase with UV absorption at 270 nm. The calibration curves of the eight polyphenols are linear (r(2) > 0.9992) over the concentration range of 0.0894-120.0 microg/mL. The mean recoveries are 95.4% to 98.1%. The results indicate that the HPLC method developed can easily be applied to the determination of eight polyphenols in the leaves of Crataegus pinnatifida Bge. var. major.