Effect of concentrated growth factor combined with mineralized collagen material on the adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells and the osteogenic effect in vivo

Abstract

To explore the effects of concentrated growth factor (CGF) combined with mineralized collagen (MC) materials on the adhesion, proliferation, and differentiation of bone marrow mesenchymal stem cells (BMSCs) and their osteogenic effects in vivo, and to provide a theoretical basis for the combined application of CGF and MC materials in bone defect regeneration and repair. CGF was prepared from venous blood of healthy volunteers, and then CGF extracts (CGFe) were prepared. In vitro experiment: human BMSCs (hBMSCs) were divided into 4 groups. Groups A, B, and C were cultured with α-MEM medium [containing 10% fetal bovine serum (FBS) and 1% double antibody] containing 2%, 5%, and 10%CGFe, respectively; group D was cultured with α-MEM medium (containing 10%FBS and 1% double antibody) without CGFe. Scanning electron microscopy was used to observe the effect of CGFe on cell adhesion. Cell counting kit 8 (CCK-8) was used to detect the effect of CGFe on cell proliferation. After osteogenic induction, alkaline phosphatase (ALP) activity was detected and Western blot was performed to detect osteopontin (OPN) expression. In vivo experiment: Eighteen New Zealand big-eared rabbits were used to prepare circular bone defect models on the left and right mandibles, and implant CGF gel (prepared from autologous venous blood)+MC material (volume ratio 1∶1, experimental group) and simple MC material (control group), respectively. At 4, 8, and 12 weeks after operation, 6 rabbits were sacrificed respectively to obtain materials, and Micro-CT scanning was performed to observe the formation of new bone and material degradation in vivo. In vitro experiments: Scanning electron microscopy showed that the cells of groups A, B, and C spread better on MC materials than group D, with more pseudopodia. CCK-8 method showed that different concentrations of CGFe could promote cell proliferation, and the absorbance ( A) value of cells cultured for 2, 3, 5, and 7 days was in the order of group C>group B>group A>group D, the differences were significant ( P<0.05). ALP activity test showed that its activity was proportional to the osteogenic induction time and CGFe concentration ( P<0.05). Western blot analysis of osteogenic induction culture for 14 days showed that the relative expression of OPN protein in groups A, B, and C was significantly higher than that in group D, and the higher the CGFe concentration, the higher the relative expression of OPN protein ( P<0.05). In vivo experiment: Micro-CT observation showed that the new bone formation and material degradation of the experimental group were better than those of the control group at 4, 8, and 12 weeks after operation. Quantitative detection showed that the volume of new bone volume, new bone volume fraction, trabeculae number, and trabecular thickness of the experimental group were significantly higher than those of the control group at each time point, the residual material volume, residual material volume fraction, and trabecular separation were significantly lower than those of the control group, all showing significant differences ( P<0.05). CGF can effectively promote the adhesion, proliferation, and osteogenic differentiation of BMSCs on MC materials, and 10%CGFe has the most significant effect. The combined application of CGF and MC material can significantly promote bone formation in vivo.