Effect of Enamel Matrix Derivative and N-Acetyl Cysteine on Proliferation and Osteogenic Activity of Dental Pulp Stem Cells

Successful bone regeneration often requires induction by signaling molecules. Enamel matrix derivative (EMD) is said to enhance initial phases of healing. N-acetyl cysteine (NAC) is a molecule assumed to enhance osteogenesis and induce osteoblastic differentiation. This study sought to compare effects of EMD and NAC on proliferation, mineralization, and enzymatic activity of dental pulp mesenchymal stem cells (DPSCs). DPSCs were cultured on mineralized bone allograft (MBA) powder. After 24 hours, EMD in concentrations of 10, 50, and 100 μg/mL and NAC in 5 mM concentration were added. Methyl thiazolyl tetrazolium (MTT) assay was used for cell proliferation assessment at 1, 2, and 3 days. Osteoblastic differentiation of DPSCs was evaluated at 30 days, by alizarin red staining and assessment of alkaline phosphatase (ALP) activity. Both EMD and NAC caused time-dependent reduction of cell proliferation compared with the negative control. Maximum proliferation of DPSCs was observed in the 10 μg/mL EMD group at all time points, whereas NAC caused higher ALP activity and mineralization of DPSCs compared with EMD. In vitro application of NAC, as a signaling molecule, may effectively enhance bone regeneration by the induction of mineralization and enzymatic activity, despite the resultant reduction in cell proliferation rate.