Effects Of Low Energy Laser On Expression Of CCL2,ICAM-1,c-Jun And C-Fos In Experimental Periodontitis Rats

ObjectivesExperimental periodontitis rat models were successfully established by lipopolysaccharide injection and orthodontic wire ligation,after removement of the ligation wire,the periodontal basic treatment and low-energy laser irradiation treatment were performed.Peripheral blood,gingival tissues and jaw samples of rats were observed to the expression of chemokine C-C motif ligand 2(CCL2),intercellular adhesion molecule-1(ICAM-1),transcription factor c-Jun and c-Fos.The changes of expression in periodontal treatment group,normal control group and periodontitis group were analyzed.In order to provide experimental basis for laser assisted treatment of periodontitis,the changes of expression in LLLI assisted SRP treatment group and SRP alone group were analyzed too.The relationship between the changes of CCL2,ICAM-1,c-Jun and c-Fos and the state of periodontal tissues was further analyzed.The possible mechanism of low-energy laser irradiation in anti-inflammatory treatment of periodontitis and the signal transduction pathways involved in transcription factors c-Jun and c-Fos in CCL2,ICAM-1 were further explored.MethodsTwenty pure 6-week old male SD rats were randomly divided into four groups with 5 in each group: group C(Normal control group),group P(experimental periodontitis group),and SRP group(experimental periodontitis + local debridement group),SRP+LLLI group(experimental periodontitis + local debridement treatment + low-energy laser irradiation group).Periodontitis model was established by ligation of the first molars on the maxillary with orthodontic wires and injection of lipopolysaccharide(LPS)from Porphyromonas gingivalis(P.g).There was no intervention in group C.SRP group was treated with removal of ligature wire and local debridement treatment.SRP+LLLI group had being received local debridement treatment combined with LLLI treatment lasted two weeks,three times a week after successful modeling.By completing the model establishment,all the rats were sacrificed,and the samples of gingival tissues,jaw and peripheral blood of each group were collected.Before the end of the experiment,the same person who was professionally trained detected the periodontal status of the experimental rat teeth.The maxillary samples were used to make continuous sections of the periodontal tissues of the teeth.The morphological changes of the gingival tissues were observed by HE staining.TRAP staining was used to observe the expression of osteoclasts in alveolar bone region.The CCL2,ICAM-1 and transcription factor c-Jun and c-Fos expression changes in the gingival tissues were observed by immunohistochemical staining.The gene expressions of CCL2,ICAM-1,c-Jun and c-Fos in peripheral blood and gingival tissues were detected by polymerase chain reaction(PCR).Results1.The gingival tissues of rats in group P were dark red with edema and congestion,hemorrhage was detected,and periodontal pockets were formed.The gingival redness and hemorrhage of SRP group were significantly improved,but still higher than the normal control group.In the SRP+LLLI group,the gums swollen and the bleeding were basically disappeared;in the C group,there was no obvious inflammatory change in the maxillary first molars.2.Under the light microscope,the thick collagen fibers were seen in group C,There was no obvious pathological manifestation of inflammation.Group P showed obvious changes.The collagen fibers in the connective tissue layer were edema and degeneration,and were replaced by the inflammatory cells.The alveolar bone showed osteoclast bone lacuna,the active osteoclasts was inside.TRAP staining revealed a large number of osteoclasts.In the SRP group,HE staining showed that inflammatory cells in periodontal tissues were significantly reduced.Alveolar bone absorption was static,osteoclasts were greatly reduced,and periodontal tissue inflammation disappeared.In the SRP+LLLI group,inflammatory cells in periodontal tissue basically disappeared,osteoclasts were basically disappeared;numberous new fibrous connective tissue was observered.3.Immunohistochemical staining showed that the expression levels of CCL2,ICAM-1,transcription factors c-Jun and c-Fos in the P group were significantly higher than those in the normal control group,while the expression of these factors was reduced in the SRP group and SRP+LLLI group as compared with the P group.Between these two groups,the expression of these factors was decreased more significant in the SRP+LLLI group.4.The results of PCR showed that the expressions of CCL2,ICAM-1,transcription factor c-Jun and c-Fos mRNA in gingival tissues and peripheral blood leukocytes of rats in the P group were significantly higher than those in the normal control group(P<0.05),the mRNA expression of CCL2,ICAM-1,transcription factor c-Jun and c-Fos in the SRP group and SRP+LLLI group was significantly lower than that in the P group(P<0.05),and the reduction was more significant in the SRP+LLLI group.Conclusion1.A rat model of experimental periodontitis in a short period of time by injecting lipopolysaccharide and ligating orthodontic wire was successfully established.This model is an effective means for studies on the characteristic histopathological changes of periodontitis,and it can provide a scientific experimental basis for the clinical study of periodontal disease,this has important significance for the treatment of periodontitis.2.This study confirmed that the expression of CCL2,ICAM-1,transcription factors c-Jun,c-Fos in gingival tissues and peripheral blood of rats in periodontitis group was significantly higher than that in the normal control group,indicating that CCL2,ICAM-1,transcription factors c-Jun and c-Fos played a key role in the development of periodontitis.3.During the development of periodontal inflammation,CCL2,ICAM-1,transcription factors c-Jun and c-Fos express both in gingival tissues and peripheral blood,this indicates that periodontitis is closely related to the systemic diseases.Inflammatory factors in the periodontal tissues also circulate throughout the whole body with blood,and thus cause adverse reactions other systems the whole body.4.After SRP treatment,the levels of CCL2,ICAM-1,transcription factors c-Jun and c-Fos in gingival tissues and peripheral blood were significantly decreased and their levels of decline were consistent with the degree of the periodontal inflammation.650 nm semiconductor low-energy laser assisted periodontal basic therapy further improved periodontal tissue inflammation and reduced levels of inflammatory factors,suggesting that LLLI can have a good therapeutic effect on chronic periodontitis in rats,and effectively reduce the degree of inflammation and destruction of periodontal tissues.