The Expression Of MMP-9 And COX-2 Under Different Interventions In Experimental Periodontitis

Objective:Through the removal of ligation lines,scaling and scaling combined with minocycline intervention to evaluate the expression of matrix metalloproteinase-9 and cyclooxygenase-2 on experimental periodontitis.Methods: Thirty male SD rats were used in the present study.Five main groups were created as follows: normal group(no periodontitis,no intervention),periodontitis group,free-wire periodontitis group(ligatures were removed after periodontitis-induced),scaling applied group(scaling were given after periodontitis-induced)and scaling and minocycline applied group(scaling and minocycline applied after periodontitis-induced),6 rats in each group.Experimental periodontitis was induced via ligating 4-0 silk sutures around maxillary first molar teeth on the left for 15 days.Rats of control group and periodontitis group were euthanized at 15 th day.Other groups were given intervention for 15 days and were euthanized at 30 th day.During the period record PD,GI and other relevant indicators in each group.Maxillary were removed and periodontal tissue was stained by HE staining and TRAP staining.Immunohisto chemical were used to detect the expression of COX-2 and MMP-9 in rat periodontal tissue.By ELISA analysis of the levels of COX-2 and MMP-9 in serum.Results: 1.General observation showed that there was no inflammation in the normal group;The gingival of the left maxillary first molar in the oral cavity were dark red,swollen and gingival crevicular fluid oozesin in the gingival sulcus,easy to bleed after probing and periodontal pockets existed in the periodontitis group.Free-wire periodontitis group,scaling applied group and scaling and minocycline applied group are better than before,PD and GI were significantly better than the periodontitis group.2.HE staining showed that no inflammation in the normal group;the periodontitis group had obvious ulcers,proliferation of gingival epithelial pegs,the movement of the junctional epithelium towards the root to form periodontal pockets,there were obvious inflammatory cells in the lamina propria,and collagen fibers were arranged disorderly.The inflammatory cells decreased relatively in the free-wire periodontitis group.And the inflammatory cells were significantly reduced in the scaling applied group and scaling and minocycline applied group.3.TRAP staining showed that there were almost no osteoclasts in the normal group.There was many bone resorption lacuna contained osteoclasts which are diverse and multinucleated at the alveolar ridge in the periodontitis group.The number of osteoclasts in the free-wire periodontitis group,the scaling applied group and the scaling and minocycline applied group was decreased compared with the periodontitis group.4.Immunohistochemical staining showed that the expression of COX-2 and MMP-9 in the normal group,the scaling applied group and the scaling and minocycline applied group was significantly lower than the periodontitis group(P<0.05),but there was no statistically significant difference between the free-wire periodontitis group and the periodontitis group(P>0.05).5.ELISA results showed that the expression of the normal group,the scaling applied group and the scaling and minocycline applied group were significantly lower than the periodontitis group after intervention(P<0.05).But there was no statistically significant difference between the free-wire periodontitis group and the periodontitis group(P>0.05).Conclusion: Through three intervention treatment which is free-ligament,scaling and scaling and minocycline the inflammatory infiltration and osteoclast tissue in the periodontal tissue were decreased.The MMP-9 and COX-2 levels in gingival tissue and peripheral blood were significantly decreased and the decrease level was consistent with the relief of periodontal inflammation.The scaling and minocycline had the most significant decrease,but there was no significant difference between the free-wire periodontitis group and the periodontitis group.