Effects of cyclic equibiaxial mechanical stretch on α-BK and TRPV4 expression in equine chondrocytes

BACKGROUND: Chondrocytes are regularly exposed to load-induced stimuli and have the capability to sense and respond to applied mechanical stress. However, the mechanisms involved in chondrocyte mechanotransduction are not clearly understood. The purpose of this study was to explore the effects of cyclic equibiaxial mechanical stretch on the expression of α-BK and TRPV4 channels. FINDINGS: Freshly isolated equine articular chondrocytes were subjected to mechanical stress (8% elongation at frequency of 0.5 Hz for 8 h). Western blotting was used to investigate the expression of BK(Ca) and TRPV4 channel proteins. Mechanical stretch increased the expression of BK(Ca) channels by 1.8 fold but TRPV4 expression was not affected. CONCLUSIONS: Upregulation of BK(Ca) channel may be the result of direct membrane stretch or elevated intracellular Ca(2+).