Effect of Growth/Differentiation Factor-5 on human dental pulp cell

Growth/Differentiation factor-5 (GDF-5) is a multifunctional protein and close related to the development and repair of multiple tissues, including cartilage, tendon, intervertebral disk, bone and skin. Objectives: The purpose of this study is to investigate whether GDF-5 influences the morphological changes, cell proliferation and viability, cell differentiation and extracellular matrix formation of human dental pulp cells in vitro within the period of 5 or 10 days. Methods: primary-cultured human dental pulp cells were treated with different concentration of GDF (0-500 ng/ml). Morphology of pulp cells was observed under light microscopy (100X). Cell proliferation was evaluated by MTT assay. Cell differentiation was evaluated by alkaline phosphatase (ALP) staining and ALP quantitative assay. Collagen content was determined by Sircol Collagen assay. Difference between control and experimental groups are analyzed by One-way analyses of variance (ANOVA) and post hoc Tukey test. Results: Human dental pulp cells were spindle with extended cellular processes with/without GDF-5 treatment. Under the treatment by various concentration of GDF-5: cell viability was up-regulated significantly in dose-dependent manner. GDF-5 declined the ALP activity of human dental pulp cells. GDF-5 did not affect the collagen content. Conclusion: GDF-5 demonstrated proliferative property in human dental pulp cells, but had inhibitory effect on cell differentiation and no effect on extracellular matrix formation. These events are crucial in the mechanism of pulpal repair and regeneration