Study On The Expression Of EphrinB2/EphB4 In Alveolar Bone Of Rat Periodontitis Model

ObjectiveAn experimental rat alveolar bone resorption model was established by ligation of the cervical part in two sides of the first molar of rats and ligation with application of Porphyromonas gingivalis,and by observing gum color,texture,tooth looseness,radiographic to show that the periodontitis animal model was successfully established.The pathological status of alveolar bone resorption was observed by HE staining,and immunohistochemistry was used to explore the expression of ephrin B2 and Eph B4,Providing new ideas for the prevention and treatment of periodontal disease.Methods1、Twenty-four 4-week-old male Sprague-Dawley(SD)rats were randomly divided into three groups:control group,ligation with cervical part in two sides of the first molar of rats group,ligation in the same way and inoculated with P.g.The concentration of inoculated P.g was 1×10~9CFU/ml.All rats were fed with common food and water,and the indoor temperature was about 25℃.2、Observe the gums color,texture and tooth mobility of the three groups At week 4 and 8,and then kill 4 rats in each group in batches.The maxillary was peeled off and examined by radiographic.After that,the alveola bone resorption of the first molars were analyzed and measured.3、The first molar was fixed with 4%PFA after isolated from the maxillary,then dehydrated,embedded,and sectioned.He staining was used to analyze the inflammation around the teeth and the state of the bone resorption.4、Analysis the expression of Eph B4 receptor and its ligand ephrin B2 with immunohistoche in rats experimental periodontitis model.Resuits1、In the control group,there was no abnormal changes the gums of the maxillary first molars,no blooding was probing and there was no alveolar bone absorption;At week 4,slight edema was seen in the ligation group and the ligation+P.g group and food residues and materia alba were attached to the ligation site.The gums were bleeding and there was periodontal pocket and attachment loss during searched and the affected teeth become loose;At week8,the gums in the ligation group and the ligation+P.g group were dark red,and the Inter-proximal papilla were eroded.There was more materia alba around the teeth,and the teeth mobility degree become more obvious.2、The alveolar bone of maxillary first molar in the ligation group and the ligation+P.g group has different degrees of absorption at week 4 and 8.In this two groups,the attachment loss has reached the tooth root 1/3.In the same period,the alveolar bone of the ligation+P.g group was more destructed seriously than the ligation group(P<0.05).The alveolar bone at week 8 was more greater than those at week 4 when the experimental groups were under the same treatment factors.3、The He staining showed that there were no statistical significance aboue the maxillary first molars in the control group.The junctional epithelium was located in cementum enamel boundary,with the tooth body unio n close,infiltrates not inflammatory,and the periodontal ligament fibroblasts were regular;At week 4 and 8,the periodontal ligament fibroblasts were disordered with infiltrates inflammatory,the bone trabecula become porouser,a large number of activated osteoclasts appear at the edge of alveolar bone,and more macrophages can also be seen in the bone marrow cavity.4、Immunohistochemical results showed that Eph B4 was more expressed in the marginal area of normal alveolar bone tissue,especially in osteoblasts,but only a small amount in osteoclasts.During alveolar bone resorption,Ephrin B2 had a relatively high expression level in osteoclasts,especially in the alveolar bone resorption area.Eph B4:The expression in the ligation group and the ligation+P.g group increased with the increase of time(P<0.05).At the same weeks,the expression in the ligation group and the ligation+P.g group was higher than that in the control group(P<0.05).And the expression in the the ligation+P.g group was higher than that in the ligation group(P<0.05).Ephrin B2:the expression of the ligation group and the ligation+P.g group increased with the increase of time.At the same weeks,the expressions in the ligated group and the ligated+P.g group were increased compared with the control group,and the ligated+P.g was higher than the ligated group,but there were no statistical significance.ConclusionThe experimental periodontitis model of the maxillary first molar of rats can be successfully established by ligating or ligating with inoculated P.g.Theresults of immunohistochemistry show that Eph B4 is elevated,indicating that the forward pathway is activated,which promotes osteogenic differentiation.There was a small increase in ephrin B2,but it was not statistically significant,showing that osteoclast inhibition by the reverse pathway was not obvious.