Abstract: PURPOSE: To analyze the expression levels of miR-218-5p and miR-153-3p in gingival crevicular fluid (GCF) and serum of patients with chronic periodontitis (CP), and to explore their clinical significance. METHODS: A total of 142 CP patients admitted to Wuhan Third Hospital from September 2022 to September 2024 were selected as the CP group, which was further divided into mild CP subgroup (n=56), moderate CP subgroup (n=51), and severe CP subgroup (n=35). Meanwhile, 80 individuals with healthy periodontium were selected as the control group. qRT-PCR was used to detect the relative expression levels of miR-218-5p and miR-153-3p in GCF and serum of subjects in both groups. Pearson correlation analysis was performed to explore the correlations between these two microRNAs and periodontal probing depth (PD), attachment loss at the cementoenamel junction (AL), and plaque index (PLI). Spearman correlation analysis was used to analyze the associations between the two microRNAs and the severity of CP. Receiver operating characteristic (ROC) curves were constructed to evaluate the efficacy of miR-218-5p and miR-153-3p in predicting moderate to severe CP. RESULTS: The proportion of patients with smoking history, PD, AL and PLI in the CP group were significantly higher than those in the periodontally healthy group (P<0.05). The expression levels of miR-218-5p and miR-153-3p in GCF and serum of the CP group were significantly lower than those in the periodontally healthy group (P<0.05). With the aggravation of CP severity, the expression levels of miR-218-5p and miR-153-3p gradually decreased, and the levels in the severe CP subgroup were significantly lower than those in the moderate and mild CP subgroups (P<0.05). Pearson analysis showed that the expression levels of miR-218-5p and miR-153-3p in GCF and serum of CP patients were negatively correlated with PD, AL, and PLI (P<0.05). Spearman analysis showed that both microRNAs were negatively correlated with the severity of CP (P<0.05). ROC curve analysis revealed that the areas under the curve (AUC) of GCF miR-218-5p, GCF miR-153-3p, serum miR-218-5p, and serum miR-153-3p for predicting moderate-to-severe CP were 0.784, 0.796, 0.749 and 0.684, respectively. The AUC of the combined detection of the four markers increased to 0.909, with significantly improved sensitivity (81.13%) and specificity (91.67%, P<0.01). CONCLUSIONS: The expression levels of miR-218-5p and miR-153-3p in GCF and serum of CP patients are significantly decreased, which are negatively correlated with the degree of periodontal destruction and disease severity. These two microRNAs can be used as effective indicators for predicting the occurrence of moderate-to-severe CP.

Key words: Chronic periodontitis, miR-218-5p, miR-153-3p, Gingival crevicular fluid, Serum, Biomarker