Effects of inflammatory microenvironment mediated by macrophage on the proliferation and osteogenic differentiation of periodontal ligament cells / 口腔疾病防治

ABSTRACT

Objective@#The present study investigated the effects of the inflammatory microenvironment mediated by macrophages on the proliferation and osteogenic differentiation of periodontal ligament cells (PDLCs).@*Methods@#Conditioned medium containing inflammatory factors was collected following macrophage activation with 1 μg/mL lipopolysaccharide (LPS). PDLCs were isolated from healthy teeth and cultured in conditioned medium (LPS-CM group) or normal medium (control group), and the proliferation of PDLCs was detected using the MTT assay. The cells were cocultured with an osteogenic inducer for 3 d and 7 d, and the alkaline phosphatase (ALP) activity of PDLCs was detected using an ALP kit. The mRNA expression levels of runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and collagen I (COL-I) were detected using real-time PCR, and the protein levels of RUNX2, OCN, and COL-I were detected using Western blotting. Mineralization nodules were observed using Alizarin red staining after osteoinduction for 14 d. @*Results@#The OD value of PDLCs in the LPS-CM group was lower than that in the control group (P < 0.05). The mRNA levels of RUNX2, OCN, and COL-I in the LPS-CM group were lower than those in the control group (P < 0.05). In addition to the OCN 3 d group (t = 2.75, P = 0.056), the protein expression of RUNX2, OCN, and COL-I in the LPS-CM group was lower than that in the control group (P < 0.05). However, the ALP activity of the LPS-CM group was higher than that of the control group, which was 1.58-fold greater (t = 5.91, P = 0.030) at 3 d and 1.29-fold greater (t = 6.01, P = 0.046) at 7 d. The number of calcified nodules in the LPS-CM group was significantly less than that in the control group (t = 8.63, P = 0.048). @*Conclusion@# The inflammatory microenvironment mediated by macrophages may inhibit the proliferation and osteogenic differentiation of PDLCs.