Effect of nano-hydroxyapatite suspension on cell proliferation and cycle in human periodontal ligament cells.

: The study was aimed to provide insights into the effect of nano-hydroxyapatite (nHA) suspension on cell proliferation and cycle of human periodontal ligament cells, offering the evidence for nHA being used in periodontal therapy. Human periodontal ligament cells (HPDLCs) were cultured in different concentrations of nano-hydroxyapatite/sodium carboxymethyl cellulose (nHA-CMCNa) suspension in vitro. After that, cell proliferation ability was examined by MTT [3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and flow cytometry. MTT assay demonstrated that the Relative Proliferation Rate (RPR) of 0.5% nHA-CMCNa group was significantly higher than other groups (p <0.05), which means that nHA-CMCNa might increase cell proliferation ability. Flow cytometry showed that cells in G1 phase decreased, whilst cells in S phase increased after cultured in nHA-CMCNa suspension for 48 h. The result suggested that part of cells finished G1 phase in advance and get into S phase earlier, which speed up the cell proliferation, nHA-CMCNa suspension had great effect on cell proliferation. The high concentration of nHA-CMCNa could shorten the time in G1 phase, impel part of cells into S phase, and accelerate proliferation rate of HPDLCs.