OBJECTIVETo investigate the early effects of the cyclic uniaxial compressive stress on Actin and Vimentin of the rat condylar chondrocyte.

METHODSThe third-passage chondrocyte were harvested from the mandibular condyles of 2-day-old rats, and a cellular compressive stress device was used to apply stress on cells at 4 000 microstrain for 15, 30, 60, 120, 240 min. The early effects of the cyclic uniaxial compressive stress on Actin and Vimentin of the rat mandibular condylar chondrocytes were examined by laser scanning confocal microscope (LSCM), immunofluorescence technique and Western blot.

RESULTSThe expression of fluorescent light of cys-toskeleton protein changed obviously with 4000 microstrain compressive stress loading. The expression of Actin significantly decreased in 60 min, and the expression of Vimentin decreased in 30 min. Then the expression of these two protein recovered in 120 min.

CONCLUSIONThere are time-responsiveness between the 4000 microstrain compressive stress stimulate and Actin, Vimentin. It shows the expression of Actin and Vimentin down-regulated at first under the compressive stress, then increased by feedback. It hints that there are "self-regulate" mechanisms in the cell response to mechanics stimulate.