Experimental study of transforming growth factor-β3 combined with dental pulp stem cells in promoting the implant's osseointegration

Abstract

Objective: To investigate the effect of transforming growth factor-β3 (TGF-β3) and dental pulp stem cells (DPSC) in promoting the implant's osteointegration. Methods: Thirty-three New Zealand white rabbits were randomly divided into phosphate buffer saline (PBS) group, DPSC group and TGF-β3 + DPSC group (12 rabbits/group). Two teeth from the rabbits's mandibular incisors or molars were pulled out randomly, then implant were placed in the tooth extraction site immediately. In PBS group, the implant area was filled with Bio-Oss powder 0.30 g mixed by PBS 20 μl only; while the implant area was filled with Bio-oss powder 0.30 g and 1×10(8)/L DPSC 20 μl in DPSC group; in the the TGF-β3+DPSC group the implant area was filled with Bio-Oss powder 0.30 g mixed with 1×10(8)/L DPSC 20 μl and 80 μg/L TGF-β3 20 μl. Eighteen New Zealand rabbits were executed in the 4 weeks and 8 weeks respectively. The treated alveolar bone tissue and implant were collected for plastic section. Alizarin red staining (ARS), immunohistochemical detection (IHC) of bone sialoprotein (BSP), osteocalcin (OC) and type Ⅰ collagen (COL-Ⅰ) were performed after 4 weeks and 8 weeks. Combined bone lamelta width (CBLW) and implant bone contact rate (IBCR), trabecular width (TW) and trabecular area percentage (TA) were observed by histomorphometric measurement. Results: ARS staining: 4 weeks after the operation, the TGF-β3+ DPSC group showed more red calcified nodules than the other two groups; 8 weeks after operation, the red calcified nodule was further increased. 4 weeks after the operation, the expression of BSP, OC and COL-Ⅰ was (0.35± 0.04), (0.36 ± 0.03) and (0.39 ± 0.01) respectively in TGF-β3+ DPSC group, (0.27 ± 0.02), (0.24 ± 0.01) and (0.28±0.03) respectively in DPSC group, and (0.13±0.03), (0.15±0.02) and (0.16±0.02) respectively in PBS group. Eight weeks after operation, the expression of BSP, OC and COL-Ⅰ was (0.51±0.02), (0.49±0.03) and (0.53±0.02) respectively in TGF-β3+DPSC group, (0.35±0.02), (0.37±0.01) and (0.38±0.01) respectively in DPSC group, and (0.21±0.03), (0.19±0.01) and (0.22±0.02) respectively in PBS group. After 4 weeks and 8 weeks, the expression of BSP, OC and COL-Ⅰ in TGF-β3+DPSC group were significantly higher than the other groups (P<0.05), there was no significant difference between DPSC group and PBS group (P>0.05). Eight weeks after operation, the CBLW, IBCR, TW and TA around implant in TGF-β3+ DPSC group were significantly higher than that in the other groups (P<0.05), there was no significant difference between DPSC group and PBS group (P>0.05). Conclusions: The DPSC has the potential osteogenic differentiation ability; TGF-β3 can accelerate the osteogenic differentiation of DPSC to some extent; TGF-β3 combined with DPSC can effectively promote the implant's osseointegration.