ObjectiveTo investigate the role of miRNA-200c/sex determining region Y-box 2 (SOX2) axis in alveolar bone resorption in experimental periodontitis.
MethodsC57BL/6 mice were randomly divided into blank group, model group, miRNA-200c group and combination group.Mice in the model group, miRNA-200c group and combination group were given lentiviral empty vector, miRNA-200c lentiviral overexpression vector, miRNA-200c plus SOX2 lentiviral overexpression vector, respectively.Chronic mice periodontitis models were established by smearing Porphyromonas gingivalis in the oral cavity of mice in model group, miRNA-200c group and combination group.The expression levels of miRNA-200c and SOX2, gingival index, and distance from the cementoenamel junction (CEJ) to the alveolar bone crest (ABC) were determined in the periodontal tissues of mice in all groups.HE staining was used to analyze the pathomorphological changes of periodontal tissues of mice.The expression levels of miRNA-200c and SOX2 in periodontal tissues of mice were detected by qPCR.The protein expression levels of osteoprotegerin (OPG), receptor activator of nuclear factor-κB ligand (RANKL), and receptor activator of nuclear factor-κB (RANK) in periodontal tissues of mice were detected by Western blotting.
ResultsCompared with the blank group, the expression level of miRNA-200c in the periodontal tissue of the model group decreased (P < 0.05), and the expression level of SOX2 increased (P < 0.05).The expression level of miRNA-200c in the periodontal tissue of the miRNA-200c group was higher than that of the blank group and model group, and the expression level of SOX2 was lower than that of the model group (P < 0.05).The expression levels of miRNA-200c and SOX2 in the periodontal tissue of the combination group were higher than those of the blank group and model group (P < 0.05).The gingival index and the distance from CEJ to ABC in the model group, miRNA-200c group and combination group were higher than those in the blank group (P < 0.05), which in the miRNA-200c group were lower than those in the model group (P < 0.05), and which in the combination group were higher than those in the miRNA-200c group (P < 0.05).The results of Western blotting showed that the expression levels of RANKL and RANK, and the ratio of RANK/OPG in the model group, miRNA-200c group and combination group were higher than those in the blank group (P < 0.05), which in the miRNA-200c group were lower than those in the model group (P < 0.05), and which in the combination group were higher than those in the miRNA-200c group (P < 0.05).The results of HE staining showed that a large number of inflammatory cells infiltrated in the periodontal tissue of mice in the model group, and collagen fibers were disordered, denatured and broken; compared with the model group, these symptoms in the miRNA-200c group were significantly alleviated; compared with the miRNA-200c group, mice in the combination group also showed significant inflammatory cell infiltration, and collagen fibers were disordered, denatured and broken.The detection of luciferase activity showed that miRNA-200c mimic could significantly reduce the activity of wild-type SOX2 luciferase (P < 0.01), but there was no significant difference in the activity of mutant SOX2 luciferase (P>0.05).
ConclusionsMiRNA-200c can improve the inflammatory response and alveolar bone resorption in mice with periodontitis, which may be related to the RANKL/RANK/OPG axis regulated by SOX2.
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