Enhancement of Odontoblastic Differentiation of Stem Cells from Exfoliated Deciduous Tooth Using N-acetylcysteine—An In Vitro Study

Abstract

The study was conducted to evaluate the effects of N-acetylcysteine (NAC) on the propagation and differentiation of stem cells from human exfoliated deciduous teeth(SHED). SHEDs were isolated by explant culture method and characterized for stem cell properties using flow cytometry method. MTT assay and Cell Counting Kit-8 (CCK-8) assay were used to examine the viability and proliferation of the SHEDs. The effects of NAC-induced osteo/odontoblastic differentiation of SHEDs were determined by functional staining for mineralization, and the gene expression of osteo/odontoblastic transcription factors and proteins was evaluated by real-time quantitative reverse transcription-polymerase chain reaction(qRT-PCR) analyses. Protein levels of collagen type 1 (COL1), dentin sialophosphoprotein (DSPP), and dentin matrix acidic phosphoprotein 1(DMP-1) were calculated by the Western blot method to assess the osteo/odontogenic differentiation. SHEDs presented mesenchymal stem cell (MSC)-like characteristics on flow cytometric analysis. The cell viability and metabolic activity of SHEDs were increased with an increase in the concentrations of NAC from 0.5 to 10 nM. However, the concentrations of NAC from 0.5 to 2.5 mM did not affect cell proliferation. NAC incorporated at a concentration of 2.5 mM showed higher mineralization and considerably increased gene expression levels of runt-related transcription factor 2 (RUNX2), COL1A1, DSPP, and DMP-1. It significantly increased the protein expression of odontoblast-related matrix proteins like COL1, DSPP, and DMP-1. NAC regulates the healthy propagation of dental stem cells in vitro. Its effects on the differentiation of dental pulp SHEDs remain unidentified. This study explores that NAC can encourage the mineralization of SHEDs and differentiate them into the odontoblastic lineage. The results propose that NAC could have a significant pharmacological role in activating and enhancing odontogenic differentiation of dental stem cells and possibly a prospect in regenerative dentistry.