OBJECTIVETo observe activating protein-1 (AP- 1) members in response to changes of wall-shear stress in osteoblastic cells in vitro.

METHODSIsolated and purified osteoblastic cells from the calvaria of newborn SD rats were cultured and subcultured. The third generation cells were subjected to wall-shear stress of 0.8 Pa, 1.2 Pa, 1.4 Pa and 1.6 Pa separately. Gene expression of the seven AP-1 members were studied before (0 h) and 10 min, 15 min, 30 min, 60 min after treated with wall-shear stress.

RESULTSThe expression of FosB, c-Fos, c-Jun, JunD and JunB mRNA increased transiently after application of 1.2 Pa wall-shear stress in osteoblastic cells compared to 0.8 Pa , 1.4 Pa and 1.6 Pa stress, and peaked at 15 min.

CONCLUSIONMechanical environment changes in osteoblastic cells induced a dramatic induction of most of the AP-1 members.