Increased cyclooxygenase 2 expression in association with oral lichen planus severity

Abstract

Background/purpose Although some studies have shown induction of cyclooxygenase 2 (COX-2) in oral lichen planus (OLP), an association between COX-2 upregulation and OLP clinical severity has not been investigated. Therefore, we aimed to compare COX-2 expression in OLP with that in normal oral tissues, and to determine correlations between COX-2 expression and both clinical criteria and visual analog scale (VAS) scores. Materials and methods COX-2 expression was studied in 25 OLP and 13 normal oral tissues by immunohistochemistry. Both clinical criteria and VAS scores were used to evaluate the clinical severity of OLP. The differences in COX-2 expression between OLP and normal tissues, and the correlations between COX-2 expression and clinical severity were determined by the nonparametric statistical tests. Results COX-2 expression was significantly increased in OLP epithelium when compared with normal epithelium (P < 0.001), and intense COX-2 staining in inflammatory infiltrates was observed in the OLP lamina propria. COX-2 expression in OLP epithelium and inflammatory infiltrates was significantly correlated with the clinical criteria score ( r = 0.428, P = 0.007, and r = 0.681, P < 0.001, respectively), whereas a significant correlation with the VAS score was observed only in OLP inflammatory infiltrates ( r = 0.605, P < 0.001). Conclusion Enhanced COX-2 expression in both OLP epithelium and inflammatory infiltrates correlates well with the clinical severity. An association between VAS score and COX-2 expression in OLP inflammatory infiltrates suggests an important role of additional COX-2 expression from inflammation in causing pain in OLP patients.

Immunohistochemical evaluation of the effect of acitretin and systemic steroid treatments on Ki‐67, Bcl‐2, and COX‐2 levels in cutaneous lichen planus patients

“…17 Compared with normal epithelium, COX-2 expression was significantly increased in the oral LP epithelium, which correlated with disease severity. 30 El-Rifaie et al 16 have shown that COX-2 expression in cutaneous LP patients is higher than in normal skin. Our study did not support this.…”

“…Expression of the COX‐2 gene can be suppressed by anti‐inflammatory cytokines (IL‐4, IL‐10, etc) and glucocorticoids . Compared with normal epithelium, COX‐2 expression was significantly increased in the oral LP epithelium, which correlated with disease severity …”

Changes in Proportions of Linoleic Acid-derived Oxylipins in Oral Lichen Planus

“…With respect to (i) an obvious candidate is COX-2, since this enzyme converts linoleic acid to hydroperoxylinoleates (HPODEs), which are then reduced to HODEs (9). Increased COX-2 activity is a hallmark of OLP (4,5). However, both 9-and 13-HODE are produced by this pathway (9), and so a change in the relative proportions of 9-HODE and 13-HODE would not be expected.…”

Elucidating the role of Cyclooxygenase‐2 in the pathogenesis of oral lichen planus – an immunohistochemical study with supportive histochemical analysis

“…This is, however, in contrast to what has been reported previously by Lysitsa et al who did not find any difference in COX‐2 expression among the various clinical types of OLP. However, Chankong et al found that increased COX‐2 expression was associated with the severity of oral lichen planus.…”