| Objective: To investigate the expression and distribution of TLR-4 in periodontal ligament of rats during orthodontic tooth movement, and to realize the function of the periodontal ligament under the orthodontic force. Methods: 60 SD rats were randomly categorized into experimental and control group whereas 5 SD rats were in blank group. The model of tooth movement was established by applying orthodontic appliance to control and experimental group. Only orthodontic force was administered in the experimental group. The rats were monitored during the experiment and were sacrificed on day 1, 3, 5, 7, 10, 14 of the experiment respectively. The alveolar bone of the experiment area was dissected out and test the expression and distribution of TLR-4 in periodontal ligament. Results: In the comparison of continuous weak expression of TLR-4 in control group, an increased expression of TLR-4 was observed on day 1 of tooth movement in experimental group. The expression of TLR-4 reached the maximum on days 5 then decreased, and it returned to baseline level on days 14 of tooth movement. TLR-4 localized mainly in cytoplasm of periodontal ligament fibroblasts. Conclusion: Orthodontic force evokes the increase in the expression of TLR-4 which varies in a time dependant manner in periodontal ligament. As an inflammation mediator, TLR-4 may play a role in periodontal remodeling during orthodontic tooth movement. |
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