A preliminary evaluation of quercetin-mediated osteogenic gene expression in lipopolysaccharide-treated human periodontal ligament cells: an in vitro study

AIM: This study aimed to evaluate the effect of quercetin on osteogenic gene expression in lipopolysaccharide (LPS) stimulated human periodontal ligament cells (hPDLCs) under in vitro conditions. MATERIALS AND METHODS: hPDLCs were cultured with LPS for 24 hours to simulate an inflammatory microenvironment. Following this pre-stimulation, cells were treated with quercetin at concentrations of 2.5 µM, 5 µM, and 10 µM for up to 14 days. No further exposure to LPS was performed during the subsequent culture period. The mRNA expression levels of osteogenic markers, osteopontin (OPN) and osteocalcin (OCN), were assessed on day 14 using Quantitative Real-Time PCR (RT-qPCR). Statistical analysis was performed using Welch's one-way ANOVA with Holm-adjusted post hoc comparisons. RESULTS: LPS stimulation significantly suppressed the expression of both OPN and OCN compared with the control group. However, quercetin treatment restored and dose-dependently increased the expression of these markers, with the greatest effect observed at 10 µM. At this concentration, OPN and OCN expression levels reached 5.80 ± 0.26 and 6.62 ± 0.30, respectively, relative to the control. A consistent dose-dependent upregulation was observed for both markers, indicating restoration of osteogenic gene expression. CONCLUSION: Quercetin modulates the expression of osteogenic markers, including OPN and OCN, in LPS-stimulated hPDLCs under in vitro conditions. These findings suggest a potential modulatory role for quercetin in influencing osteogenic gene expression. However, additional in vitro functional assays and in vivo studies are necessary to establish its role in periodontal regeneration.