Abstract

Objectives: This study investigated the association of miRNA-181-5p, miRNA-150-5p, miRNA-146a-5p, and miRNA-16-5p, and inflammatory genes linked to the NF-kappa B pathway in patients with symptomatic and asymptomatic apical periodontitis. Materials and methods: A cross-sectional study was conducted involving apical tissues from asymptomatic apical periodontitis (AAP, n = 17), symptomatic apical periodontitis (SAP, n = 15), and healthy periodontal ligament (HPL, n = 16). Expression levels of miRNA-181-5p, miRNA-150-5p, miRNA-146a-5p, and miRNA-16-5p, along with mRNA levels of IL-6, VEGF-A, HIF-1 alpha, and NF-kappa B, were quantified using qPCR. Data were analyzed through descriptive statistics and regression models, including mediation analysis conducted using STATA V14 (p < 0.05). Results: mRNA levels of IL-6, VEGF-A, and NF-kappa B were significantly higher in SAP compared to HPL (p < 0.05), while AAP did not show differences (p > 0.05). Also, no significant differences were observed in HIF-1 alpha expression among the groups (p > 0.05). miRNA-181-5p, miRNA-16-5p, and miRNA-146a-5p were downregulated in both AAP and SAP, compared to HPL (p < 0.05), whereas miRNA-150-5p was upregulated (p < 0.05). Negative correlations were found between miRNA-181-5p and miRNA-16-5p with IL-6, and between miRNA-181-5p and VEGF-A in AP forms (p < 0.05). Mediation analysis revealed that the upregulation of IL-6 mRNA was mediated by miRNA-16-5p in SAP. Conclusions: Apical periodontitis is associated with the downregulation of miRNA-181-5p, miRNA-16-5p, and miRNA-146a-5p and the upregulation of miRNA-150-5p. IL-6 mRNA levels seem to be regulated by miRNA-16-5p during SAP.