[Experimental study on the transforming growth factor β3 combined with dental pulp stem cells in early bone...

Objective: To establish the experimental model of rabbit mandibular anterior implant repair and evaluate the effects of transforming growth factor (TGF)-β3 and dental pulp stem cells (DPSC) in promoting the bone integration of implant. Methods: The New Zealand rabbits were randomly divided into experimental group, control group and blank group (6 rabbits for each group) . In the experimental group, the implant area was filled with the mixture of TGF-β3, DPSC and Bio-oss powder. In the control group, the implant area was filled with the mixture of DPSC and Bio-oss powder. In the blank group, the implant area was filled with the mixture of phosphate buffer solution and Bio-oss powder. Eighteen New Zealand rabbits were sacrificed in 2 weeks after procedure. The treated alveolar bone tissue was observed. The bone tissue around the implant were estimated by HE staining, immunocytochemical staining and real-time quantitative PCR. Results: The implants were no shedding nor loose. HE staining shows the blank group had a sparse trabecular bone and a small amount of blood vessel around the implant and no obvious new bone formation. The control group showed that the bone trabecula around the implant was sparse and slender, the osteoblasts were arranged linearly around the trabecular bone, a small amount of new bone formation was found around the implant. In the experimental group, there were more thick and dense trabecular bone around the implant, the surrounding osteoblasts were arranged in clusters. The osteoblasts were active and many new bone formed. Typical bone lacunae, bone cells and a large number of new blood vessels can be observed. Immunohistochemistry showed that the proportion of average positive area in the experimental group, control group, blank group were (24.6±5.3) %, (11.3±2.8) % and (7.6±3.8) % respectively. The expression of bone sialoprotein in experimental group were significantly higher than the other 2 groups(P=0.000). Real-time quantitative PCR results showed that the expression level of Runt-related transcription factor 2 (RUNX2), type Ⅰcollagen (COL-Ⅰ), alkaline phosphatase in the experimental group was higher than in the blank group. The expression level of RUNX2 and COL-Ⅰ in the experimental group was higher than that of the control group (P=0.023). Conclusions: TGF-β3 has potential to promote the transformation of DPSC into osteoblasts, which can promote the integration of bone around the implant.