Study On The Expression Of Bcl-2, Bax As Well As Their Relationship With Apoptosis And Proliferation Activity In Periodontal Ligament Fibroblast Under The Influence Of Different Occlusal Forces

Objective: To study the relationship between apoptosis, proliferation and remodel of periodontal ligament after changes of occlusal force. Methods: Animal models of changes in occlusal force were established by extracting the right first, second and third maxillary molars in SD rats (n=60). Morphologic changes and apoptosis, proliferation of periodontal ligament fibroblast (PDLF) were detected by histology, transmission electron microscopy and immunohistochemistry. Results: Animal model of changes in occlusal force was successfully established. The results of histology showed that the structure of periodontium were derangement and the nuclears of PDLF were pycnosis, intranuclear chromatin condensed in experimental group. Immunohistochemical staining showed that the expression of Bcl-2 and Bax were time-dependent in both low occlusal force (LF) and high occlusal force (HF) groups, the levels of apopototic cells reached its peak at 12h, but the expression of proliferating nuclear antigen (PCNA) peaked on day 3, and then gradually decreased to normal level. Conclusion: The model can be used to study the influence of occlusal force change on periodontium. Changes of occlusal force can facilitate the PDLF apoptosis and promote PDLF proliferation, contributing to the remodeling of periodontal ligament.