To investigate the effects of type Ⅱ a histone deacetylase inhibitor LMK-235 during early osteoblast/odontoblast differentiation in hPDLCs.

hPDLCs were obtained by the collagenase digestion method. hPDLCs at the 3^rd passage were treated with medium containing 10% fetal bovine serum mixed with different concentrations of LMK-235 (0, 50, 100, 250, 500 nmol/L), respectively. Proliferative capability of hPDLCs was tested by MTT and qRT-PCR was used to detect mRNA expression levels of Runx2, ALP and DMP-1 3 d later.

MTT assay showed that cell proliferation in hPDLCs treated with 100 nmol/L LMK-235 was increased significantly compared with the control group (P＜0.05). The expression of Runx2 mRNA in the 100 nmol/L group was 1.77 times of the control groups (P＜0.05). The expressions of ALP mRNA in all the experimental groups were significantly higher than that in control groups (P＜0.05), and the expression in the 100 nmol/L groups was the highest. The expressions of DMP-1 mRNA in the 50 and 100 nmol/L groups were higher than the control groups (P＜0.05).

Type Ⅱ a histone deacetylase inhibitor LMK-235 could accelerate cell proliferation in hPDLCs at the concentration of 100 nmol/L, and regulate early osteoblast/odontoblast differentiation by upregulating the mRNA expressions of Runx2, ALP and DMP-1.