Mechanotransduction in bone. OC: osteocyte; OB: osteoblast; OCL: osteoclast; Pre-OB: preosteoblast; Pre-OCL: preosteoclast; PG’s: prostaglandin (E2 and I); RANK-L: receptor activating NFκB-Ligand; OPG: osteoprotegerin; IGF: insulin-like growth factor; TGF: transforming growth factor; Scl: sclerostin; PTHrP: parathyroid hormone related peptide. Osteocytes sense the fluid flow induced by loading in the lacunocanalicular system; this signal modulates the secretion in the bone microenvironment of factors which can increase bone remodeling while stimulating osteoblast differentiation and activity (green arrows) and decreasing osteoclast activity (red arrow), resulting locally in a positive bone balance.
