Addition of BMP-2 or BMP-6 to dexamethasone, ascorbic acid, and β-glycerophosphate may not enhance osteogenic differentiation of human periodontal ligament cells

Abstract

This study was designed to investigate the potential merits of the combined use of bone morphogenetic protein (BMP)-2 or BMP-6 and osteogenic supplements (OS) [dexamethasone, ascorbic acid (AA), and β-glycerophosphate] on osteogenic differentiation of periodontal ligament cells (PDLCs). Osteogenic differentiation was evaluated by quantitative alkaline phosphatase (ALP) assay, alizarin red staining, quantitative calcium assay, and the qRT-PCR analysis for the expression of collagen type I, runt-related transcription factor-2, osteopontin (OPN), and osteocalcin in PDLCs. Culture with BMP-2 or BMP-6+AA increased ALP activity of PDLCs, suggesting their osteo-inductive effects. However, longer duration of culture showed neither of the BMPs induced in vitro mineralization. In contrast, OS were able to increase ALP activity and OPN expressions, and also induced in vitro mineralization. The mineralization ability was not enhanced by the addition of BMP-2 or BMP-6. These findings suggest that the addition of BMP-2 or BMP-6 to OS may not enhance an osteogenic differentiation of hPDLCs.

Keywords::

• Human periodontal ligament cells
• bone morphogenetic protein-2 and -6
• dexamethasone
• ascorbic acid
• β-glycerophosphate

Acknowledgments

The authors thank Ms. Anna-Maija Honkala for her excellent technical assistance. We are indebted to Ms. Bettina Lindroos for her constructive comments of the manuscript.

Declaration of interest: This work was supported by the Finnish Funding Agency for Technology and Innovation (TEKES), competitive Research Funding of Pirkanmaa hospital district and University of Tampere. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.