Transcription factor and bone marrow stromal cells in osseointegration of dental implants

Titanium implants are widely used in dental clinics and orthopaedic surgery. However, bone formation surrounding the implant is relatively slow after inserting the implant. The current study assessed the effects of bone marrow stromal cells (BMSCs) with forced expression of special AT-rich sequence-binding protein 2 (SATB2) on the osseointegration of titanium implants. To determine whether SATB2 overexpression in BMSCs can enhance the osseointegration of implants, BMSCs were infected with the retrovirus encoding Satb2 (pBABE-Satb2) and were locally applied to bone defects before implanting the titanium implants in the mouse femur. Seven and twentyone days after implantation, the femora were isolated for immunohistochemical (IHC) staining, haematoxylin eosin (H&E) staining, real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR), and micro-computed tomography (μCT) analysis. IHC staining analysis revealed that SATB2-overexpressing BMSCs were intensely distributed in the bone tissue surrounding the implant. Histological analysis showed that SATB2overexpressing BMSCs significantly enhanced new bone formation and bone-to-implant contact 3 weeks after implantation. Real-time qRT-PCR results showed that the local delivery of SATB2-overexpressing BMSCs enhanced expression levels of potent osteogenic transcription factors and bone matrix proteins in the implantation sites. μCT analysis demonstrated that SATB2-overexpressing BMSCs significantly increased the density of the newly formed bone surrounding the implant 3 weeks postoperatively. These results conclude that local delivery of SATB2-overexpressing BMSCs significantly accelerates osseointegration of titanium implants. These results provide support for future pharmacological and clinical applications of SATB2, which accelerates bone regeneration around titanium implants.