PDLSCs Proliferation, Mineralization and Migration on Fluorapatite and Bone Surfaces

Objectives: Periodontal ligament stem cells (PDLSCs), an important source for depositing cementum and synthesizing fibrous tissue, can potentially regenerate periodontal ligaments (PDL) between bioactive implant surface and alveolar bones. In our previous studies, the fluorapatite (FA) coated implant surface has been shown to support the growth and stimulate differentiation and mineralization of various mesenchymal SCs in vitro and the bone-like tissue formation in vivo. However, the behavior of PDLSCs on this FA surface and alveolar bone has not been studied. The objective of this study is to compare the proliferation, mineralization and migration of PDLSCs on FA coated metal surfaces and bone surfaces.
Methods: The PDLSCs were subcultured in 20% DMEM up to four weeks on the two surfaces. Cell-counting, SEM and DNA quantitation were used to analyze the cell initial attachment and proliferation. Alkaline phosphatase (ALP) staining at day 14, 21, Alizarin red staining at day 28 were used to observe the differentiation and mineralization of these PDLSCs. Migration study was carried out using Transwell model after the cell growth for 24 hours.
Results: Both surfaces were biocompatible and supported the long-term growth of the PDLSCs. Consistent with cell counting, both DNA quantitation result and SEM images showed a higher rate of initial cell attachment and proliferation on the bone surface compared to FA surface. Stronger ALP staining was observed on FA surfaces. Positive Alizarin red staining was only seen on the FA surfaces. Significantly more PDLSCs migrate towards bone and FA surfaces compared to Transwell surface.
Conclusions: This study indicated that FA surfaces are suitable for the PDL regeneration and functional anchorage of PDL fibers using PDLSCs. PDLSCs have the potential to migrate towards both the FA and bone surfaces, which mimics the natural formation of PDL from PDLSCs and shows promising potential in future dental regenerative applications.