Salmon DNA Accelerates Bone Regeneration by Inducing Osteoblast Migration

Abstract

The initial step of bone regeneration requires the migration of osteogenic cells to defective sites. Our previous studies suggest that a salmon DNA-based scaffold can promote the bone regeneration of calvarial defects in rats. We speculate that the salmon DNA may possess osteoinductive properties, including the homing of migrating osteogenic cells. In the present study, we investigated the influence of the salmon DNA on osteoblastic differentiation and induction of osteoblast migration using MG63 cells (human preosteoblasts) in vitro. Moreover, we analyzed the bone regeneration of a critical-sized in vivo calvarial bone defect (CSD) model in rats. The salmon DNA enhanced both mRNA and protein expression of the osteogenesis-related factors, runt-related transcription factor 2 (Runx2), alkaline phosphatase, and osterix (OSX) in the MG63 cells, compared with the cultivation using osteogenic induction medium alone. From the histochemical and immunohistochemical assays using frozen sections of the bone defects from animals that were implanted with DNA disks, many cells were found to express aldehyde dehydrogenase 1, one of the markers for mesenchymal stem cells. In addition, OSX was observed in the replaced connective tissue of the bone defects. These findings indicate that the DNA induced the migration and accumulation of osteogenic cells to the regenerative tissue. Furthermore, an in vitro transwell migration assay showed that the addition of DNA enhanced an induction of osteoblast migration, compared with the medium alone. The implantation of the DNA disks promoted bone regeneration in the CSD of rats, compared with that of collagen disks. These results indicate that the salmon DNA enhanced osteoblastic differentiation and induction of migration, resulting in the facilitation of bone regeneration.

Degradation rate of DNA scaffolds and bone regeneration

“…We previously reported that 300 bp DNA/protamine scaffolds disappear early after implantation into rat calvarial bone defects . We also showed that high molecular weight DNA, as used in the present experiments, promotes new bone formation by attracting osteoblasts . The addition of DNA to preosteoblast cultures promotes osteogenic differentiation and cellular migration in vitro .…”

“…Some reports have indicated that extracellular phosphate promotes osteogenic differentiation and calcification of preosteoblasts and mesenchymal stem cells . Furthermore, we have recently shown that the DNA itself enhances osteogenesis by increasing phosphate transporter activity and cell migration, resulting in new bone formation in a calvarial defect model.…”

“…To prepare the scaffold for implantation, the DNA paste was injected into a silicone mold (8 mm internal diameter; 0.8 mm height) on a polytetrafluoroethylene plate and then frozen with liquid nitrogen . The fabricated DNA disks were immediately and carefully removed from the silicon mold and dried for 24 h in an FD‐5N freeze dryer.…”

“…Each µ‐CT slice was 18 µm thick. After scaffold materials transiently provide a space and/or support structure during osteogenesis, bone healing has been reported to require for 3–6 months . Therefore, samples were harvested at 2, 4, 8, and 12 weeks after implantation in cranial implant experiments ( n = 5 each group at each time point).…”

Susceptibility of the Wnt/β-catenin Pathway Accelerates Osteogenic Differentiation of Human Periodontal Ligament Stem Cell Spheroids

“…In this study, enhanced staining with ALP was observed in spheroid-derived HPLSCs cultured with OIM. Similarly, spheroid-derived HPLSCs cultured with OIM showed increased expression levels of Runx2 and osterix, which are known markers of the early stage of osteogenesis 27,30,31) , by western blot analysis. These findings indicate that, as compared with monolayer-derived HPLSCs, HPLSC spheroids are more susceptible to osteogenic differentiation, resulting in accelerated osteogenic differentiation in the early stage.…”