Effects of enamel matrix derivative on proliferation and differentiation of primary osteoblasts

Objective. The aim of this study was to investigate the effects of enamel matrix derivative (EMD) on proliferation, protein synthesis, and mineralization in primary mouse osteoblasts. Study design. Osteoblasts were obtained from mouse calvaria by enzymatic digestion and grown in monolayer together with EMD (2-100 mug/ml). Metabolic activity and cell proliferation were determined by tetrazolium salt assay (MTT) and by 5-bromo-2'-deoxyuridine (BrdU) incorporation. For differentiation studies, a 3-dimensional organoid culture system was used. Osteoblastic differentiation was estimated by alkaline phosphatase (ALP) activity and calcium content. Collagen synthesis was assessed by [H-3]-proline incorporation. Morphologic observations were made by electron microscopy. Results. EMD treatments increased metabolic cell activity and BrdU incorporation. In the organoid cultures, ALP activity and calcium accumulation were enhanced by EMD treatment, but [H-3]-proline incorporation was not. Morphologically, an increased deposition of mineralized nodules was found. Conclusions. EMD treatment enhanced cellular activities of primary osteoblasts and might support the regeneration of periodontal bony defects.