This study evaluated the expression of genes involved in the concentration of Ca2+ in precursor osteoblast-like cell, MC3T3-E1 subjected to stretching stimuli. Transient receptor potential vanilloid 4 (Trpv4) gene expression, the factor that is activated by stretch stimulation and enables inflow of Ca2+ from the extracellular space, was not affected as a result of stretch stimulation; conversely, the expression of sodium-calcium exchanger 1 (Ncx1) gene involved in outflow of intracellular Ca2+ increased, depending on stimulation intensity. Localization of Ca2+ correlated with the positioning of the endoplasmic reticulum, and intracellular Ca2+ decreased in inverse proportion to the intensity of the stretching force. These results suggest that stretch stimulation activates intracellular Ca2+ elimination rather than Ca2+ uptake before osteoblast differentiation.
Keywords: Ncx1; Ncx3; Trpv4; osteoblast differentiation; stretch stimulus.