Effects of biaxial mechanical stimulation on cyclooxygenase-2 expression in rat primary osteoblasts

Objective To study the effects of uniform biaxial mechanical stimulation on cyclooxygenase (COX-2) expression in SD rat primary osteoblasts. Methods A new uniform biaxial mechanical stimulation model has been designed for the first time. The isolated rat primary osteoblasts were exposed to uniform biaxial mechanical stimulation at different intensities (20 000, 100 000 and 200 000 microstrains) for different time periods (2, 4 and 8 h). The expression changes of COX-2 protein caused by respective mechanical stimulation were detected by immunocytochemistry and Western blotting. Results The expression of COX-2 did not increase sigmificantly after mechanical stimulation for two hours, but was upregulated after four hour and eight hour stimulation, while in the control groups, nearly no COX-2 was expressed. In additon, the expression of COX-2 in four-hour stimulated group increased while in the eight-hour group decreased with mcreasing stimulation. Conclusion Uniform biaxial mechanical stimulation at a certain time period and intensity promotes the expression of COX-2 in rat primary osteoblasts.