Exploring the Role of Micro-RNA Expression in the Pathogenesis of Recurrent Aphthous Ulceration in Nigerian Patients: A Preliminary Investigation

Recurrent aphthous ulceration (RAU) is one of the most prevalent oral mucosal conditions, characterized by painful recurring oral ulcers with an incompletely understood etiopathogenesis. Emerging evidence suggests that dysregulated micro-RNA (miRNA) expression may play a role in the inflammatory and epithelial disruption processes underlying RAU. This preliminary investigative study examines the differential expression of selected miRNAs in the oral mucosal tissue of patients with confirmed RAU compared to healthy controls at University College Hospital Ibadan, South West Nigeria. Twenty patients with confirmed major or minor aphthous ulcers and 20 age- and sex-matched controls provided biopsy samples from ulcer margins and corresponding normal mucosal sites. Real-time quantitative PCR was used to quantify expression levels of miR-21, miR-155, and miR-146a, which are established regulators of inflammatory signaling. Hematological and immunological profiles including complete blood count, serum ferritin, vitamin B12, and folate were obtained from all participants. Results demonstrate upregulation of miR-21 and miR-155 in ulcer margin tissue of RAU patients compared to controls, with a concurrent decrease in miR-146a expression suggesting dysregulated NF-kB pathway activation. Hematological deficiencies were identified in 35% of RAU patients but did not correlate with miRNA levels. These preliminary findings suggest a miRNA-mediated inflammatory mechanism in RAU pathogenesis and warrant larger mechanistic studies in the Nigerian population. Keywords: recurrent aphthous ulceration, micro-RNA, inflammation, Ibadan, oral mucosal pathology.