RESUMO
BACKGROUND:As an important cytokine, interleukin-6 regulates immune responses in inflammation sites and has an autocrine/paracrine activity that stimulates osteoclast formation and bone resorption, which is related to bone remodeling during orthodontic tooth movement. OBJECTIVE:To investigate the effects of orthodontic force on the expression of interleukin-6 mRNA in the periodontal tissue of rats. METHODS:In situ hybridization was performed to measure the expression of interleukin-6 mRNA at 1, 3, 5, 7, 10 and 14 days after the application of orthodontic force on the maxil ary first molars of rats. RESULTS AND CONCLUSION:The expression of interleukin-6 mRNA was observed at a low level in the normal periodontal tissue of rats. After the application of force, the induction of interleukin-6 mRNA was observed to reach a maximum on day 3 and to decline thereafter. The expression of interleukin-6 mRNA can be evoked by orthodontic force but with a certain self-limiting. As a multifunctional cytokine, interleukin-6 plays a very important role in periodontal remodeling during orthodontic tooth movement.
RESUMO
Objective; To investigate the expression and distribution of IL-6 in periodontal tissues and the change of the alveolar bone of rats during orthodontic tooth movement, and to study the effects of orthodontic force on the periodontal tissue remodeling. Methods: SO gram orthodontic force was loaded on the left first maxillary molars of 25 rats in experimental group. Immunohistochem-istry and histomorphometric analysis were performed to measure the expression of IL-6 and the loss of alveolar bone at 0, 1, 3, 5, 7 " and 10 days after the application of orthodontic force. Results; The expression of IL-6 was observed to reach maximum level on day 3 and to decline thereafter in experimental group. No obvious alveolar bone loss was detected in the mesial side of the first molars. Conclusion; Although orthodontic force can evoke the local inflammatory response of periodontal tissue and the expression of pro-inflammation cytokines such as IL-6, it can not cause severe periodontal destruction and alveolar bone loss.