| Objective:Periodontitis is one of the most common oral diseases.A lot of studies have shown that the progress of periodontitis is closely related to host immune response.Macrophage migration inhibitory factor(MIF)is an inflammatory cytokine,several studies have shown that MIF plays an important role in the control of chronic diseases such as rheumatoid arthritis and glomerulonephritis.However,the function of MIF in periodontitis is still not clear.Receptor Activator for Nuclear Factor-κB Ligand(RANKL)belongs to the family of tumor necrosis foctor ligands,and plays an important role in bone resorption.Based on that,this study was designed to investigate the levels of MIF and RANKL in saliva and gingival crevicular fluid in healthy and severe chronic periodontitis patients before and after non-surgical treatment.And analyze the correlation between periodontal clinical indexes,the relative content of Porphyromonas gingivalis(P.gingivalis)and expression level of MIF.To investigate the expression and variation characteristics of MIF in the progress of periodontal tissue destruction.Provides reference for clinical diagnosis and treatment of severe chronic periodontitis.Methods:1.Subjects20 persons with healthy periodontal conditions and 23 cases with severe chronic periodontitis who visited the department of periodontology,school of stomatology,China medical university from August 2016 to August 2017 were included in this study.Inclusion criteria: without systemic disease,women without pregnancy,did not take any antibiotics for at least 3 months,did not have periodontal treatment for at least 6 months,no smoking,no history of orthodontic treatment.The study protocol was reviewed and approved by the local ethics committee ethical review(2015-12).Participants were enrolled into the study after signing an informed consent.2.Selection of index teethSix index teeth in each participant were selected according to the community periodontal index(CPI).All index teeth should meet the criteria as follows: no caries,noperiapical disease,no crown repair and no extraction indications.If the index teeth do not meet the conditions above,then select the adjacent teeth instead.3.Clinical examinationAll severe chronic periodontitis patients were treated with periodontal treatment and divided into pre-treatment group and post-treatment group.The clinical examination of all patients with severe chronic periodontitis was performed by the same physician,according to the consistency test,the Kappa value is greater than 0.75.including probing depth(PD),attachment loss(AL),bleeding index(BI).4.Samples collection and analysisThe gingival crevicular fluid was collected from 6 index teeth of each subject and inserts into a 1.5 ml EP tube with 200 ul PBS(phosphate-buffered saline).Then the tubes were placed on a shaker table for 1 h and vortexed briefly then store it at-80℃.The unstimulated whole saliva samples were collected in 5 ml EP tubes.MIF and RANKL concentrations were measured by enzyme-linked immunosorbent assay(ELISA).5.Detection of P.gingivalis in subgingival plaqueThe subgingival plaques of the index teeth at baseline and one month after treatment were collected from the periodontitis group and the healthy control group,respectively.Subgingival plaque DNA was extracted and the relative content of P.gingivalis was detected by Real-time PCR.6.Statistical analysisSPSS 24.0 statistical software package performed statistical analysis on all the data obtained.The clinical index was expressed as mean ± standard deviation.We used t-tests to compare the differences between groups.Non-normal distribution data were expressed as median and quartile.The non-parametric tests were used to compare the differences between groups and Spearman conducted correlation analysis.Results:1.Expression of MIF was detected in gingival crevicular fluid and saliva samples form all subjects.However,92% of saliva samples and 90% of GCF samples were negative for RANKL.2.The levels of MIF in saliva and GCF were significantly higher in severe periodontitis patients [166.93(187.30)ng/ml and 112.51(188.72)ng/ml,respectively]than healthy control group [23.05(36.78)ng/ml and 24.92(25.82)ng/ml,respectively],the difference was statistically significant(P <0.05).3.The clinical indexes PD,AL,BI of severe periodontitis patients were decreased significantly after periodontal treatment((35)PD=﹣1.32;(35)AL=﹣0.95;(35)BI=﹣2.17),the difference was statistically significant(P <0.05).4.Ratio of P.gingivalis to total bacteria in subgingival plaque of severe chronic periodontitis was higher than the healthy controls group(P <0.05).After the initial therapy,the proportion of P.gingivalis in total bacteria decreased significantly((35)P.gingivalis%=0.490),the difference was statistically significant(P <0.05).5.MIF levels in saliva and GCF were significantly decreased in patients with severe chronic periodontitis after non-surgical treatment(81.91 ng/ml and 60.85 ng/ml,respectively),the difference was statistically significant(P <0.05).MIF levels in saliva and GCF were still higher than that of health control group,the difference was statistically significant(P <0.05).6.The level of MIF in GCF was positively correlated with PD in patients with severe chronic periodontitis(r =0.486,P =0.019).There was a correlation between MIF levels in GCF and saliva before treatment and after treatment(r =0.700,P <0.01;r=0.791,P <0.01).Conclusions:The levels of MIF in gingival crevicular fluid and saliva were significantly higher in patients with severe chronic periodontitis than those in periodontally healthy subjects,and their concentrations decreased significantly after periodontal treatment.The level of MIF in gingival crevicular fluid of patients with severe chronic periodontitis is positively correlated with PD,which may have a certain clinical value,indicating that MIF is involved in the development of severe chronic periodontitis,and its expression level can be used as an indicator of inflammatory markers to judge activity and inflammation indexes of chronic periodontitis. |
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