Purpose: This study was designed to investigate the effect of enamel derivative matrix (EMD) on the proliferation, mineralization, and differentiation of human mesenchymal stem cells (hMSCs).
Material and methods: For the proliferation assay, water-soluble tetrazolium salt-8 tests were carried out after culturing for 24 and 48 h. For the evaluation of mineralization, Alizarin red S (ARS) tests were performed after 21 days of culturing in an osteogenic medium. In order to investigate some of the bone-related proteins, namely type I collagen (Col I A2), bone sialoprotein (BSP), and bone gamma-carboxyglutamate (Gla) protein (BGLAP, osteocalcin), real-time polymerase chain reaction (RT-PCR) tests were carried out after 2, 3, and 4 weeks of culturing, respectively.
Results: The activity of proliferation and mineralization increased significantly depending on the concentration of EMD (P<0.05). In the control group, the expression of Col I A2 decreased, but EMD enhanced its expression over time and was correlated to the concentration. The amount of expression of BSP in this group increased over time, but EMD strikingly suppressed its expression in the fourth week. As well, the amount of expression of BGLAP increased as the culture duration lengthened in the control group. However, the expression of BGLAP was suppressed in the experimental group with EMD.
Conclusion: Within the limits of this study, EMD enhanced the proliferation of hMSCs. After evaluation with ARS staining, EMD seemed to enhance mineralization, and the RT-PCR test revealed that EMD promoted early-stage osteoblast differentiation by enhancing Col I A2 expression, but exerted an inhibitory effect on the mineralization by lowering the gene expression of BSP and BGLAP. Mineralized nodules formed with EMD may be composed of substances other than normal bone. Because most of the organic matrix of bone is type I collagen, which acts as the mineralization site, bone or bone-like mineralized mass might have been formed in spite of the different components of the non-collagenous proteins.