Oral mucosal changes in tight junction proteins in patients with oral lichen planus

Abstract Objective This study aimed to investigate the expression of tight junction, its distribution pattern in oral lichen planus samples and its potential association with the severity of oral lichen planus. Materials and Methods Cross‐sectional study designs were conducted. Transcriptome sequencing was conducted using oral mucosal tissues from 22 patients with oral lichen planus and 11 healthy controls. Immunohistochemistry and quantitative reverse transcription PCR were performed to verify the expression of claudin‐1, claudin‐4, occludin and zonula occludens‐1 in oral mucosal tissues from another 30 patients with oral lichen planus and 26 healthy controls. The relationship between tight junction protein expression and oral lichen planus severity was explored using correlation analysis. Results 5603 and 2475 differentially expressed genes were upregulated and downregulated respectively, in oral lichen planus tissues. KEGG analysis showed that tight junctions including CLDN1 , CLDN4 , OCLN and TJP1 were downregulated in oral lichen planus. Claudin‐1, claudin‐4, occludin and zonula occludens‐1 expression was verified to be significantly lower in oral lichen planus. Furthermore, correlation analyses showed that decreased occludin expression was positively related to oral lichen planus severity. Conclusion Decreased expression of TJ barrier proteins may be associated with the development of oral lichen planus.