OR37 - Magnesium Promotes Dentinogenesis of Human Dental Pulp Cells Through SMAD/MAPK Signaling Pathway

Abstract: Magnesium-based biomaterials might provide an innovative therapeutic potential to substantially enhance regeneration of dental tissues. In previous work, magnesium has been considered for its potential ability to enhance cell attachment and proliferation rate of human dental pulp cells (HDPCs). However, to date the dentinogenic effect of magnesium ( Mg 2+) and the underlying mechanism has not been investigated. This study was designed to compare the stimulatory effects of different concentrations of Mg 2+on odontogenic differentiation of HDPCs and to explore the associated signaling pathway. HDPCs were cultured with 0.5mM, 1mM, 2mM, 4mM, 8mM concentrations of supplemental MgCl2, 0 mM as the negative control group. Cell Viability was investigated. Odontogenic differentiation was assessed by evaluating alkaline phosphatase (ALP) activity. Mineralization and expression of odontogenic related proteins (dentin sialoprotein (DSP), dentin matrix protein 1 (DMP-1), dentin sialophosphoprotein (DSPP), collagen type I (COL-I) were analyzed. Expression of bone morphogenic protein (BMP-2), phosphorylated smad 1/5/9, p-38, P38, p-JNK,JNK, p-ERK1/2, ERK1/2 mitogen activated protein kinase (MAPK) were investigated. Statistical analysis using Muti-way ANOVA with Wilk's lambda test. 0.5mM and 1mM Mg2+elicited the highest stimulatory effect on cell viability, ALP activity, expression of DSP, DMP-1, DSPP, COL-I, and mineralization compared to the negative control (p < 0.0001). Upregulatory effect on expression of BMP-2, phosphorylated Smad 1/5/9, p-38, p-JNK, down regulation of p-ERK 1/2 compared to negative control (p < 0.0001). This is the first study to reveal the dentinogenic effect of Mg 2+on HDPCs and the associated SMAD/MAPK signaling pathway.