Influence of TRPV1 Modulators Capsaicin and Capsazepine on Osteoclastogenesis in vitro

Mohan Gowda C.M , Sreepriya M

The influence of TRPV1 modulators capsaicin and capsazepine to regulate the growth and proliferation of osteoclasts and thereby control osteoclastogenesis was studied on murine macrophage cell line RAW 264.7 induced to take up osteoclastic lineage by the addition of RANK (receptor activator of nuclear factor kappa B) ligand. The differentiation of cells of macrophage lineage into osteoclastic lineage upon the addition of RANK ligand was ascertained by TRAP (Tartarate Resistant Acid Phosphatase) staining and subsequent light microscopy analysis. Crystal violet test, Sulphorhodamine B assay, NBT reduction test and Neutral red dye uptake test were taken as end point indicators to assess osteoclast growth and proliferation. It was observed that capsaicin at a concentration of 200µg/ml exhibited a statistically significant increase whereas capsazepine at a concentration of 94.2µg/ml (IC50 concentration of capsazepine) exhibited a statistically significant inhibition of osteoclast growth and proliferation. Results of the study indicate that both the compounds influence osteoclastogenesis with capsaicin showing a potentiating and capsazepine showing inhibitory effect thereby implicating their ability to influence bone resorption and hence bone remodeling. The compounds could be of therapeutic importance in musculoskeletal diseases and other inflammatory diseases of the bone to regulate the disruption in bone remodeling equilibrium.