| Objective: To study the changes of pathology and interleukin 17 in periodontal tissue during different times of periodontitis with Immunohistochemical method and HE staining by observing the experimental animal model of periodontitis of molar with occlusal trauma in rats. To further explore the relation between occlusal trauma and periodontitis,and provide better methods for the treatment of the clinical work.Methods: Choosing 120 healthy male Wistar rats, 3 months old, weighing 250 to 280 g. Oral hygiene was good,there was no oral disease, the occluding relation was good. They were randomly divided into four groups: control group(CG)、occlusal trauma group(OG)、periodontitis group(PG)、occlusal trauma with periodontitis group(OPG), each group had 30 rats. Then each group was divided into 6 groups according to 1 d, 3 d, 1 w, 2 w, 4 w, 6 w, each group had 5 rats.The rats were anesthetized and disinfection.For general anesthesia, rats were injected 100g/L chloralic hydras intraperitoneally in accordance with 3ml/kg per injection.Bilateral oral mucosa were disinfect with 1% tincture of iodine and 75% alcohol. In OG group, each rat bonding orthodontic wire of 1-2 mm long, 0.6 mm wide with light curing composite resin on the left side of the maxillary first molar. The occlusal surface were raised 0.5-0.8mm to create the occlusal trauma.In PG group,each rat was ligated with diameter of 0.2 mm metal ligation silk on the cervical of left mandibular first molar, and as far as possible inside the gingival sulcus. In OPG group,each rat bonding orthodontic wire of 1-2 mm long, 0.6 mm wide with light curing composite resin on the left side of the maxillary first molar, and,ligating with diameter of 0.2 mm metal ligation silk on the cervical of left mandibular first molar, and as far as possible inside the gingival sulcus.Control group didn’t receive treatment. All of the rats were in a cage without pathogens, 25 c, humidity 60% to 70%, feeding commercial feed.Five rats of each group were injected 100g/L chloralic hydras intraperitoneally injection separately in 1 day, 3 days, 1 week, 2 weeks, 4 weeks, 6 weeks and transcardial perfusion with 4% paraformaldehyde. Immediately dissectioned the regions of the left maxillary and mandibular molar periodontal tissue and removed wire ligature and impact material on experiment teeth. Fixed tissue at 4 for 48 h, and decalcified at 4 in 10% ℃ ℃EDTA for 4w before the tissue were paraffin embedding,then section tissue into 5μm slices in a midsagittal direction.Study the changes of pathology and interleukin 17 positive cell in periodontal tissue with Immunohistochemical method and HE staining. Used image analysis software Image Pro Plus 6.0 to analysize the result of IL-17 immunohistochemical staining. Used SPSS 13.0 statistical software to analysis the data.Results: 1 HE staining 1.1 Control groupThere was no significant difference in dyeing results between each group of the control group.The distribution of periodontal ligament fiber was neat. The direction of cell arrangement was parallel to the long axis of the fiber bundle.The top of apical periodontal ligament was closely linked with alveolar bone. The surface of cementum was smooth and clean, the periodontal membrane near the cementum can see flat cementoblast.Critical surface in periodontal membrane and alveolar bone was level off, you can see osteoblasts. The blood vessels can be seen in the periodontal tissue and there was almost no blood cells. 1.2 Experience groupThe OG group: In the 1d group,the result was similar with the control group,in the periodontal tissue we can’t see obvious change.In the 3d group,the symptom of experimental molar was lighter,fibrous connective tissue was disordered arrangement,we can see the phenomenon of capillary expansion.In the 1w group,fibrous connective tissue was disordered arrangement obviously,there were some osteoclasts on the alveolar bone surface. In the 2w group,the number of osteoclast was increased.In the 4w group,the number of osteoclast up to the most active,there was a significant bone resorption,the lesion degree reached the peak.In the 6w group,the lesion degree gradually reduced,but there was still visible osteoclast.There was no big change in gums.The PG group:in the 1d group,the symptom of experimental molar was lighter,fibrous connective tissue was disordered arrangement.In the 3d group,we can see the phenomenon of capillary expansion and epithelial spikes increased and became more longer.In the 1w group,fibrous connective tissue was disordered arrangement,we can see some Osteoclasts and the phenomenon of bone resorption.In the 2w group,there were a lot of diffuse inflammatory cells in periodontal tissue,the phenomenon of bone resorption was more serious,the bone resorption lacunae changed bigger and Osteoclast increasesd,connective tissue fiber denaturation,and the lesion degree reached the peak.In the 4w and 6w groups,the lesion degree gradually reduced.The OPG group:In the 1d group,we can see the phenomenon of capillary expansion and some inflammatory cells.In the 3d group,the fibrous connective tissue was disordered arrangement and there were some osteoclasts on the alveolar bone surface.In the 2w group,the connective tissue fiber denaturation,the number of Osteoclast increased,the phenomenon of bone resorption was more serious,and the lesion degree reached the peak.In the 4w and 6w groups, the lesion degree gradually reduced,alveolar bone damage was no longer active. 2 The immunohistochemical expression of IL-17 2.1 Control groupThere was no significant difference in dyeing results between each group of the control group.The fibroblasts of lamina propria in gingival connective tissue and periodontal membrane of the rats had a weak positive expression. 2.2 Experience groupIn 1d group,it was weak positive;in 3d group and 1W groups,the expression of IL-17 positiven cells was increased.In the periodontitis group and the occlusal trauma with periodontitis group reached the peak in 2W,and the occlusal trauma group reached the peak in 4W.After the peak,the expression of IL-17 in experiment groups decreased,but there were still a higher level expression.In each experiment group,along with the time of the experiment,the positive expression of IL-17 showed a trend of rise before it reached the peak and down after it reached the peak.We compared the groups of the corresponding same time in OG,PG and OPG,the positive expression of IL-17 was strongest positive expression in OPG. 3 The result of data analysisCompared the positive expression of OG、PG、OPG to control group with the statistical method of Kruskal-Wallis H,P<0.05,there was a obvious difference.Compared with the statistical method of Wilcoxon,in the OG and control group,in the 1d、3d groups there were not obvious difference,but in other groups there were obvious differences.In PG and control group,just in the 1d group there was not obvious difference,there were obvious differences in other groups.In the OPG and control group,there were significant differences in every two groups.Compared the all groups of OG、all groups of PG 、 all groups of OPG with the statistical method of Kruskal-Wallis H,P<0.05,there was a significant difference in OG、PG、OPG.Compared OG and OPG、PG and OPG with the statistical method of Kruskal-Wallis H,the results were all P<0.05,there were significant differences in OG and OPG、PG and OPG.Compared with the statistical method of Wilcoxon,in OG and OPG, there were significant differences in the 3d 、1w and 2w groups,in PG and OPG,there were significant differences in the 3d、1w、2w and 4w groups.Conclusions:1 The positive expression of IL-17 in periodontal tissue is positivly associated with the degree of damage of periodontal tissue.IL- 17 has a role in the periodontal inflammatory response,it may be involved in the periodontal tissue destruction.2 The damage and destruction of periodontal tissue can be caused by occlusal trauma, it maybe can cause periodontal disease,and promote the progress of periodontitis. |
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