Objective: To investigate the effect of icariin on the expression of receptor activator nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) of human periodontal ligament cells (hPDLC) inhibited by sonicated extracts of Porphyromonas gingivalis (Pg).
Methods: hPDLC were extracted from 14 premolars extracted from 11 to 18-year-old patients for orthodontic purpose and cultured. The 7th passages of hPDLC were divided into six groups, each group was stimulated with 0, 0.001, 0.01, 0.1, 1 mg/L icariin and 50 mg/L sonicated extracts for 48 h. Reverse transcription polymerase chain reaction (RT-PCR) and Western blotting were used to detect the expression of RANKL and OPG.
Results: Pg extracts group expressed more RANKL than the control group (3.60 ± 0.11 vs 1.08 ± 0.19), OPG expression decreased (0.32 ± 0.08 vs 1.01 ± 0.08), and RANKL/OPG ratio significantly increased (11.20 ± 0.13 vs 1.00 ± 0.10). Compared with control group, RANKL and OPG expression changed in groups stimulated with 0.001, 0.01, 0.1, 1 mg/L icariin. OPG expression was higher in 0.1 mg/L group than in the control (36.84 ± 0.05 vs 1.01 ± 0.08), RANKL/OPG ratio was significantly lower than the control group (0.04 ± 0.03 vs 1.00 ± 0.10) (P < 0.01).
Conclusions: The concentration of 0.1 mg/L icariin can inhibit hPDLC expression of RANKL in sonicated extracts of Pg and promote OPG expression.