Abstract: Objective To study the effect of cryopreservation on the dedifferentiation of the condylar cartilage cells. Methods Condylar cartilage was aseptically dissected from the temporomandibular joint of 2 week old New Zealand white rabbit. The condylar cartilage cells were subcultured and analyzed after culturing in vitro to the 1st passage and then frozen for 15 days as the experimental group. The cytoactive of the 2nd passage cells of the experiment group and that of the control group were assessed by inverted phase contrast microscope. Quantitative realtime PCR and Western blot technique were used to analyze the expression of Collagen Type Ⅱ, Collagen Type Ⅹ, Sox9 and Aggrecan. One-way ANOVA was performed using SPSS13.0 software package. Results The 2nd passage of the experimental group did have morphological changes, but Quantitative realtime PCR and Western blot both showed that there was no significant difference in the expression of Collagen Type Ⅱ,Collagen Type Ⅹ, Sox9 and Aggrecan between the experiment group and the control group. Both the experiment group and the control group would have a lower expression of those cartilage specific genes than the 1st passage cells. Conclusions Cell cryopreservation will not accelerate the dedifferentiation progress of condylar cartilage cells during subcultivation. That means the condylar cartilage cells cultured in vitro can be stored by cryopreservation.

Key words: condylar, Chondrocyte, cryopreservation, dedifferentiation, New Zealand white rabbit