Spatial and temporal localization of transforming growth factor-β1, bone morphogenetic protein-2, and platelet-derived growth factor-A in healing tooth extraction sockets in a rabbit model

Abstract

Purpose: The purpose of this study was to test the hypothesis that spatial and temporal localization of growth factors transforming growth factor (TGF)-β1, bone morphogenetic protein (BMP)-2, and platelet derived growth factor (PDGF)-A in a rabbit tooth extraction model correlate with the histologic events contributing toward healing. Materials and Methods: Twenty-four male New Zealand White rabbits were used in the study. Incisor teeth were extracted from both jaws, and the healing extraction socket with the surrounding jaw bone was harvested at 48 hours, 4 days, and 1, 2, 4, 8, 12, and 16 weeks. Tissues were fixed, decalcified, and processed for hematoxylin and eosin and immunohistochemical staining. The sections were stained to detect TGF-β1, BMP-2, and PDGF-A. Stained sections were then imaged, and an automated computer program was used to detect the brown 3,3′-diaminobenzidine regions representing the location of growth factors of interest. The data were collected in terms of percentage area and intensity of stain, and an analysis of variance was conducted (Tukey-Kramer and Scheffe’s test) for statistical comparison between different time points, jaws, and growth factors. These results were also compared with hematoxylin and eosin-stained histologic specimens obtained at similar time points. Results: Spatial and temporal differences in localization of TGF-β1, BMP-2, and PDGF-A were observed across all time frames in both jaws. Statistically significant differences in percentage area and intensity of brown diaminobenzidine stain were detected temporally between TGF-β1, BMP-2, and PDGF-A ( P ≤ .0001). Conclusion: The results of this study showed positive correlation between histologic events and the spatial and temporal localization of TGF-β1, BMP-2, and PDGF-A in a rabbit tooth extraction model.