| [Objective] The purpose of this experiment is to observe changes of cell area, the expression of insulin-like growth factor-1 (IGF-I) and receptor(IGF-IR) of mandibular condylar chondrocytes(MCC) stimulated by static compressive stress, so that to understand the mechanism of cell conformation and the expression of IGF-Iand IGF-IR during the process of stress induced remodeling of mandibular cartilage. [Materials and Methods] The primary MCC separated from the mandibular condylar cartilage of six neonatal SD rats were cultured in vitro. A static compressive stresswith a magnitude of 120g/cm was exerted on the third passage of MCC for 1 hour.On the time points of 0, 6, 12, 18 and 24h after the stimulation of stress, the expression of IGF-I and IGF-IR was detected in the way of immunohistochemistry. To the control groups, stress-free cells were also cultured in the same conditions and tested on the same methods according to the experiment groups. [Results] It was found that the compressive stress, when exerted on the cultured MCC for 1 hour in vitro, had significantly improved the cell area and the expression of IGF-I and IGF-IR (P<0.05). After the stress was removed, there were no significant differences of the cell area and the expression of IGF-I and IGF-IR between theexperiment groups and control groups.[Conclusion] The compressive stress with a magnitude of 120g/cm2 for 1 hour can improve the cell area and the expression of IGF-I and IGF-IR of cultured MCC in vitro, but changes of the cell area and the expression of IGF-I and IGF-IR induced by short-term compressive stress can be corrected in a certain period after the stress was removed; combined with the researches before, we can draw a conclusion that IGF-I take an active part in the functional changes of MCC under the compressive stress, of which the mechanism is the compressive stress can improve the synthesis of IGF-I and IGF-IR.
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