| Background and Object:It has been known that the orthodontic tooth movement (OTM) is the result of periodontal tissue remodeling under the mechanical of force. The tooth movement is mediated by the bones resorption on the comprise sides and by bones deposition on the tensions sides. Alveolars bones (Ab) resorption is the first step of bones remodeling during OTM. The biologic basis of the orthodontics treatments is the periodontal tissues remodeling, and the periodontal health is the guarantee of success for the orthodontic treatment. But in the recently year, with the increasing of aware the oral health cares, the number of adult orthodontic patients who with periodontal inflammation in different degrees is increasing. How the inflammatory effects the OTM and the periodontal tissues remodeling, is becoming a hotspot of international scholars. The interleukin (IL) family can promote the development of inflammation and promote the formation of osteoclast. As a new kind of inflammatory cytokines, IL-17 had been found in many bone loss diseases, such as periodontitis, rheumatoid arthritis, osteoarthritis, etc. However, few literature reported about the IL-17 expression and role in periodontitis OTM.Therefore, in present studies, we will detect the protein expression of IL-17 in GCF of the patients. By establishing experimental animal models, we also performed a qualitative, positioning and quantitative analysis of IL-17 and observed the dynamic expression under the influence of inflammatory stimulation and orthodontic force. This studies will contributed to a good stand of the IL-17 roles in the periodontal tissues remodeling and help to provides a good theoretical guidance for the orthodontics patients with a periodontal diseases.Methods:Part â… . Detect the IL-17 protein expression in GCF of orthodontic patients20 normal orthodontic patients were selected in this part. Collect the proximal and distal gingival crevicular fluid at before and after loading orthodontic force Id,3d, 7d,2W,3 W,4 W and have tested IL-17 by ELISA in each times points.Part â…¡. Observe the expression of IL-17 by establishing the experimental animal models90 Wistar rats were divided in to 5 group:blank group (Group A), normally load groups (Group B), controlled group (Group C), periodontitis and load groups (Group D), continuous loading groups (Group E). The rats were killed in batch on before loading and after loading 1d,3d,5d,7d,14d. The first molars with periodontal tissues will be made in to paraffin sections. They were used to been observed with the change of express of a IL-17 by tooth move use the HE staining and IHC.Part â…¢. To explored the mechanisms of the affect of IL-17in periodontal remodelingSelect group A and D to do further analysis. TRAP staining was used to been count the number of osteoclast cells. IHC straining was used to quantitative analysis the expression of not only RANKL but also OPG So, we can known their relationships between IL-17 and RANKL/OPG and to explore the mechanisms of IL-17 in periodontitis teeth move.Results:1. ELISA ResultIL-17 protein was expressed in normal GCF. After loading orthodontic force, the concentration of IL-17 on distal side (D) was constantly increase, raised obviously at 3d,7d and 2W (p<0.05), and reached highest at 7d (p<0.01). Then it became to fall, and finally down to the beginning level 4W later. Furthermore, the mesial side (M) IL-17 not significantly changes. Only at 7d and 2w, there was a difference between before loading (p<0.05). Between D and M, the IL-17 concentration was significant different at 3d,7d and 2W (p<0.05).2. HE ResultIn group A, the tissue space of periodontal membrane was uniform, the fibers arranged neatly and the fibroblast distributed evenly in main fiber. In group B, the tissue space of compression sites (CS) periodontal membrane became narrow after straining for 1d, and became narrower along with the formation of bone resorption lacunae after straining for 3 h,5h and 7d. In group C, junctional epithelium to root proliferation, sulcular epithelium erosion, lymphocyte and neutrophil infiltration, widening of periodontal ligament space, alveolar crest absorption can be observed. The changes of group D were similiar to group B. However, in group E, the periodontal tissue was rapidly destroyed, and the number of osteoclasts was doubled. At 14d, alveolar bone absorption to the root tip 1/3 or less, the root is absorbed, and the osteoclasts were full of field of vision.3. TRAP ResultSeveral mononuclear osteoclasts (MOC) scattered in the normal periodontal tissues, nearly no osteoclasts (OC). After loading orthodontic force 1d,3d,5d and 7d of group D, the number of MOC compared with the group C had significant differences (p<0.05). At 3d, its number reached peak mainly in the pressure side of the bone marrow, and they had a trend of fusion in periodontal. After 5d, the MOC in the periodontal membrane and local bone marrow began to return the C level at 14d. The number of OC compared with group C had significantly changes (p<0.05) at 3d,5d and 7d and got highest at 5d. At that time, the OC were in the pressure sides of the bone lacunae and proper alveolar bone marrow. At that time, the OC were in the pressure sides of the bone lacunae and proper alveolar bone marrow. From the 7d, it began to reduced to the controlled level.4. The expression of IL-17, RANKL and OPGIL-17 was localized in the cytoplasm of fibroblasts, osteoclasts and endothelial cells. We can observed that IL-17 expressed at a low level in group A, but enhanced in group B after loading. In group B, the expression reached peak at 7d, then returned to normal levels at 14d. The expression of group C was higher than group A (p<0.05). The trend of IL-17 expression in group D was similar to but stronger than group B. In group E, the expressionof IL-17 was enhanced, and continuously increased until 14d.The positive target cells of RANKL and OPG were the same, mainly located in the cytoplasm of osteoclasts, fibroblasts, endothelial cells and osteoblasts. In normal periodontal tissues, both them weakly expressed. But the expression was enhanced after loading orthodontic force in group D. RANKL got highest at 5d, then back down. The changes were consistent with the number of osteoclasts. RANKL got highest at 5d, then back down. The changes were consistent with the number of osteoclasts.OPG reached the peak at 7d, and then weakened, but still stronger than the group A at 14d.The results found that the IL-17 only have the same trend with the expression of RANKL and OPG and the number of osteoclas but also same to the RANKL/OPG ratio (R2> 0.07).Conclusion:1. There is a small amount of IL-17 in the GCF of healthy periodontal tissues, indicating that IL-17 may be related to the physiological metabolism of normal periodontal.2. Under the force, changes of IL-17 in human GCF suggesting that IL-17 play a role in the periodontal tissue remodeling.3. The expression of IL-17 was enhanced in inflammatory periodontal tissues, which indicated that IL-17 was one of the markers of periodontal inflammation4.Inflammation and orthodontic force have a synergistic reaction, which leads to the IL-17 expression increase and affects the remodeling of periodontal tissues.5. The change of IL-17 expression was consistent with the change of RANKL/OPG ratio and the number of osteoclasts, which indicated that IL-17 maybe involved in the periodontal tissue remodeling through RANKL/OPG pathway. |
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