Abstract:

Objective　The purpose of this studywas to investigate the effects of static tension-stress on proliferation of man- dibular condylar chondrocytes in rats.Methods　The fourth-passage chondrocytes were harvested from the mandibular condyles of 2- week-old SD rats. A continuous static tension-stresswas applied on the cells in vitro using a cellular static tension-stress device, and the proliferation of mandibular condylar chondrocytes were examined using a flow cytometry. The other 30 specimens in the control group were divided into six groups to examine the effects of calf serum on cellular static tension-stresswithout any stress. The experi- mental group consisted of 70 specimenswhichwere divided into seven groups under continuous static tension-stress (5kPa, 10kPa) for 0 to 12 hours. Multivariable analyseswere conducted to test the associations between proliferation of condylar chondrocytes and differ- ent continuous static tension stresses.Results　The results showed thatthe lower calf serum inhibited the proliferation of ratmandibu- lar condylar chondrocytes. There was little effect on the proliferation of chondrocytes under continuous static tension-stress (5kPa, 10kPa) for 2 hours. The proliferation of mandibular condylar chondrocytes was promoted as the application time of stress was pro- longed (0~10 hours in 5kPa groups and 0~8 hours in 10kPa groups). The maximal proliferation appeared, when the condylar chon- drocyteswere cultured under 5kPa continuous static tension-stress for 10 hours, and 8 hours under 10kPa stress (P<0.05). The proliferation of cells in the 5kPa groupwasmore obvious than in the 10kPa group (P<0.05).Conclusion　The data prove thatme- chanical stimulates in vitro can influence and regulate the growth of condylar chondrocytes. It provides experimental evidence for ad- vanced study on cellular mechanical research in functional orthopedics.

Key words: static tension-stress, mandibular condylar chondrocytes, proliferation, functional orthopedics