Time course of expression of Bcl-2 and Bax in rabbit condylar chondrocytes following forward mandibular positioning

Abstract

Objective: To clarify the expression of Bcl-2 and Bax following forward mandibular positioning (FMP) in the condylar chondrocytes of rabbits. Materials and Methods: Sixty rabbits at 8 weeks of age were randomly allocated to the experimental group (n = 36) and control group (n = 24). Rabbits in the experimental group were induced to FMP by a functional appliance. Six rabbits from the experimental group and four from the control group were sacrificed after 3 days and 1, 2, 4, 8, and 12 weeks, respectively. All the right temporomandibular joints (TMJs) were collected and the expression of Bcl-2 and Bax was evaluated by immunohistochemical staining. Results: The results showed the expression pattern of Bcl-2 and Bax during 12 weeks after FMP. The expression of Bcl-2 reached the highest level at 1 week, whereas Bax reached its maximal expression after 4 weeks. Subsequently, the expression of Bcl-2 and Bax gradually decreased. The ratio of Bcl-2/Bax began to decrease 3 days after FMP and continued to decline until 12 weeks. Conclusions: FMP with functional appliances could change the expression of Bcl-2 and Bax, which is related to apoptosis in condylar chondrocytes. © 2008 by The EH Angle Education and Research Foundation, Inc.