Icariin Promotes Dental Tissue Regeneration Through Coordinated Osteogenic, Anti-Inflammatory, Antioxidant, and Angiogenic Signaling

Abstract

The mechanisms of oral and dental tissue destruction include interconnected inflammatory, oxidative, vascular and mineralization related mechanisms, which hamper the success of conventional therapy to restore the tissue. Combining an in silico with an in vitro approach, the molecular and cellular potential of icariin as a natural therapeutic compound in Dentistry was investigated. Target prediction, protein–protein interaction analysis, functional enrichment and molecular docking analysis were used for identification of icariin associated targets. Human periodontal ligament stem cells were cultured with different concentrations of icariin (0.1, 1, 10 or 20 μM) and were assessed for viability, alkaline phosphatase activity, calcium deposition, mineralized nodule formation, expression of osteogenic markers, the production of inflammatory cytokines, oxidative stress, antioxidant activity, and the production of VEGF. PIK3CA had the largest predicted binding affinity at -9.0 kcal/mol followed by BMP2 at -8.4 kcal/mol and RUNX2 at -8.1 kcal/mol, respectively. 1 µM caused the greatest cell viability (106.75 increased) and 10 µM the greatest regenerative response, as indicated by the increase in alkaline phosphatase activity (27.73 U/mg), calcium deposition (48.25 µg/mg) and Alizarin Red S absorbance (0.915). The expression of RUNX2, BMP2, osteocalcin and the reduction in the expression of TNF-α, IL-6, and reactive oxygen species (ROS) was increased by icariin at a concentration of 10 µM. SOD activity and VEGF production were also improved. The therapeutic window was concentration dependent and found to be reduced at 20 µM. Taken together, these results indicate that icariin could be a natural compound that could be used to stimulate the regeneration of dental tissues with a combination of osteogenic, anti-inflammatory, antioxidant and angiogenic activities. Additional animal tests, pharmacokinetic studies, biomaterials delivery tests and controlled clinical trials need to be conducted for clinical translation.