Effects of different concentrations of MTA on the proliferation and differentiation of stem cells from the apical papilla

To investigate the effect of different concentrations of MTA on the proliferation and differentiation of stem cells from the apical papilla (SCAP) and the potential of the SCAP to differentiate into odontoblasts.

SCAP were cultured in different concentrations of mineral trioxide aggregate（MTA）. MTA experimental group with concentration of 0.01 mg/mL, 0.02 mg/mL, 0.1 mg/mL, 0.2 mg/mL, 1 mg/mL, 2 mg/mL, 10 mg/mL and 20 mg/mL were prepared. The number of cells at 1 day, 3 days, 5 days and 7 days were measured via a CCK-8 assay to observe the effect of MTA on SCAP proliferation. Real-time PCR was used to detect the gene expression changes. Cells cultured in alpha MEM culture containing 15% FBS without MTA were set as the control group.

When cultured for 1 d, statistically significant differences in the promotion of in vitro proliferation of SCAP were not observed between each MTA experimental group and the control group (P＞0.05). When cultured for 3 d, 5 d and 7 d, the 0.01 mg/mL MTA group presented obvious promotion of SCAP proliferation compared with the control group (P＜0.05), whereas the 0.02 mg/mL, 0.1 mg/mL, 0.2 mg/mL, 1 mg/mL groups did not presented differences with the control group (P＞0.05). The in vitro proliferation of the 2 mg/mL, 10 mg/mL and 20 mg/mL groups was lower than that of the control group (P＜0.05). Real-time PCR detection showed that the expression levels of DSPP (t＝-11.12, P < 0.05) and Runx2 (t＝-10.62, P < 0.05) in the experimental group treated with 0.01 mg/mL MTA for 7 days were higher than those in the control group.

The 0.01 mg/mL concentration of MTA significantly promotes the proliferation of SCAP and shows the best ability to induce osteogenic and odontoblast differentiation in the SCAP, whereas high concentrations of MTA inhibited the proliferation of SCAP.