Sinusoidal Electromagnetic Fields Increase Peak Bone Mass in Rats by Activating Wnt10b/ β‐Catenin in Primary Cilia of Osteoblasts

ABSTRACTExtremely low ‐frequency electromagnetic fields have been considered a potential candidate for the prevention and treatment of osteoporosis; however, their action mechanism and optimal magnetic flux density (intensity) parameter are still elusive. The present study found that 50‐Hz sinusoidal electromagnetic fields (SEMFs) at 1.8 mT increased the peak bone mass of young rats by increasing bone formation. Gene array expression studies with femoral bone samples showed that SEMFs increased the expression levels of collagen‐1α1 and Wnt10b, a critical ligand of the osteogenic Wnt/β‐catenin pathway. Con sistently, SEMFs promoted osteogenic differentiation and maturation of rat calvarial osteoblasts (ROBs) in vitro through activating the Wnt10b/β‐catenin pathway. This osteogenesis‐promoting effect of SEMFs via Wnt10b/β‐catenin signaling was found to depend on the functional integrity of prim ary cilia in osteoblasts. When the primary cilia were abrogated by small interfering RNA (siRNA) targeting IFT88, the ability of SEMFs to promote the osteogenic differentiation of ROBs through activating Wnt10b/β‐catenin signaling was blocked. Although the knockdown of Wnt10b expression with RNA interference had no effect on primary cilia, it significantly suppressed the promoting effect of SEMFs on osteoblastic differentiation/maturation. Wnt10b was normally localized at the bases of primary cilia, but it disappeared (or was released) from the cilia upon SEMF treatm...
Source: Journal of Bone and Mineral Research - Category: Orthopaedics Authors: Tags: Original Article Source Type: research