Inhibitory effects of ChondroT and its constituent herbs on RANKL-induced osteoclastogenesis.

ABSTRACT

BACKGROUND: ChondroT is a complex herbal medicine consisting of water extracts of Ostericum koreanum (Maxim.) Kitag., Lonicera japonica Thunb., Angelica gigas Nakai, Clematis manshurica Rupr., and Phellodendron amurense Rupr. (64443). Previous studies have reported that ChondroT possesses chondroprotective and anti-inflammatory, anti-osteoarthritic, and anti-hyperuricemic activities. The study is aim to demonstrate the effects of ChondroT and its five constituent herbs on receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis and the underlying mechanisms. METHODS: Osteoclastogenesis was identified in bone marrow-derived macrophages (BMDMs) by tartrate-resistant acid phosphatase (TRAP) staining assay, actin ring formation assay and the bone resorption assay. For the molecular mechanisms, activation of RANKL-induced NF-κB and MAPK signaling pathways and the expression levels of osteoclast-specific proteins were investigated by Western blotting. Cell viability was assessed by MTT assay. Actin ring formation and NF-κB translocation were evaluated by immunostaining. RESULTS: ChondroT and each of its constituent herbs significantly suppressed osteoclast differentiation dose dependently, and decreased actin ring formation as well as bone-resorbing capacity. Mechanistically, ChondroT and its constituent herbs downregulated the expressional levels of osteoclast-specific proteins such as NFATc1, c-Fos, Cathepsin K, and matrix metalloproteinase 9 (MMP9) by suppressing NF-κB translocation to nucleus and MAPKs phosphorylation at different levels. Compared to its five constituent herbs, ChondroT exhibited the best inhibitory efficiency against osteoclastogenesis. CONCLUSIONS: Taken together, ChondroT has anti-osteoclastogenesis properties by inhibiting NF-κB and MAPKs pathways. It could be considered as a potential therapeutic candidate for the treatment of osteoclast-related bone diseases.