PDGFBB-modified stem cells from apical papilla and thermosensitive hydrogel scaffolds induced bone regeneration.

Bone defects caused by cancer surgery or trauma have a strong negative impact on human health. Treatment with cell and material-based complexes provides an alternative strategy for the regeneration of damaged bone tissue. The good physical properties and suitable biodegradability of a thermosensitive hydrogel has been shown to act as a valuable scaffold. Platelet derived growth factor BB (PDGFBB) is mainly secreted by platelets and promotes the migration and angiogenesis of mesenchymal stem cells (MSCs). Although PDGFBB is known to indirectly enhance bone repair in vivo, the effects of PDGFBB on stem cells from apical papilla (SCAPs) require further investigation. In our study, the proliferation of cells was investigated by the cell counting kit-8 and live/dead staining methods. The results indicated that PDGFBB promoted the proliferation of SCAPs. Real-time polymerase chain reaction and Western blot experiments were used to detect osteogenic genes and proteins. Moreover, calvarial defects were created in Sprague-Dawley rats and different complexes implanted. The results shown by micro-CT and hematoxylin and eosin analysis demonstrated that the hydrogel combined with lentiviral supernatant-green fluorescent protein-PDGFBB significantly improved new bone formation and mineralization compared with the other three groups. In summary, our research showed that a thermosensitive hydrogel can be used as a scaffold for 3D cell culture, and PDGFBB gene-modified SCAPs can improve bone formation in calvarial defects.