METHODS: MC3T3-E1 cells were seeded on HA and treated with recombinant IL-6 or rIL-17A or combination of the two cytokines. Cell proliferation and differentiation activity were measured by MTS and alkaline phosphatase assays respectively. Observation of cell adhesion and proliferation was examined by scanning electron microscopy. Gene and protein expressions were performed on RANKL and OPG using qPCR, Western blot and ELISA.

METHODS: Prior to analyzing the ability of this novel combined herbal therapy to promote aspects of bone regeneration, its cytotoxicity was determined using MC3T3-E1 cells (pre-osteoblast model). Cell proliferation was evaluated using phase-contrast microscopy and cell differentiation was estimated using alkaline phosphatase activity. The effect of the combined herbal therapy (CUR + FLL) was also assessed in terms of mineralization in the extracellular matrix (ECM) of cultured cells. Further, to explore the molecular mechanisms of bone formation, time-dependent expression of bone-regulating protein biomarkers was also evaluated.

RESULTS: Combined herbal therapy (CUR + FLL) significantly upregulated the viability, proliferation and differentiation of MC3T3-E1 cells compared to the monotherapy of CUR or FLL. The magnitude of ECM mineralization (calcium deposition) was also higher in MC3T3-E1 cells treated with combined therapy. The time-dependent expression of bone-forming protein biomarkers revealed that the tendency of expression of these bone-regulating proteins was remarkably higher in cells treated with combined therapy.