title: Elucidating the role of Cyclooxygenase-2 in the pathogenesis of oral lichen planus - an immunohistochemical study with supportive histochemical analysis.
abstract: OBJECTIVE
  Oral lichen planus (OLP) is a chronic, inflammatory disorder that affects the oral mucous membrane. During an inflammatory response, several chemokines and cytokines are released by the cells of the immune system. Activation of MMPs, along with mast cell-derived chymase and tryptase, degrades the basement membrane structural proteins, resulting in basement membrane breaks.
  
  
  OBJECTIVE
  To investigate the association between the COX-2 expressions, presence of intact or degranulating mast cells within the connective tissue and the extent of basement membrane discontinuity in OLP cases.
  
  
  METHODS
  This study included a total of 50 formalin-fixed paraffin-embedded specimens (FFPE) of histologically confirmed cases of idiopathic oral lichen planus. A retrospective cross-sectional analysis was carried out by immunohistochemistry to study the epithelial expression of COX-2 and by the use of special stains such as toluidine blue and periodic acid-Schiff (PAS) to study the mast cell count and basement membrane changes in the oral mucosal tissue, respectively.
  
  
  RESULTS
  There was a significant (P = 0.03) association between the COX-2 expressions and mast cell count. As the intensity of COX-2 expression increased from mild to moderate or severe, the number of mast cell count almost doubled.
  
  
  CONCLUSIONS
  Interaction between upregulation of COX-2, mast cell and basement membrane sets a vicious cycle which relates to the chronic nature of the disease. Inhibitors of COX-2 may reduce the inflammatory process preceding the immune dysregulation in OLP.
authors.affiliation: Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Manipal University, Manipal, Karnataka, India.
authors.forename: Pratyush
authors.initials: P
authors.lastname: Singh
authors.affiliation: Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Manipal University, Manipal, Karnataka, India.
authors.forename: Jasleen
authors.initials: J
authors.lastname: Grover
authors.affiliation: Private Practice, Hubbali, Karnataka, India.
authors.forename: Aditi Amit
authors.initials: AA
authors.lastname: Byatnal
authors.affiliation: Department of Biostatistics, Manipal University, Manipal, Karnataka, India.
authors.forename: Vasudeva
authors.initials: V
authors.lastname: Guddattu
authors.affiliation: Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Manipal University, Manipal, Karnataka, India.
authors.forename: Raghu
authors.initials: R
authors.lastname: Radhakrishnan
authors.affiliation: Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Manipal University, Manipal, Karnataka, India.
authors.forename: Monica Charlotte
authors.initials: MC
authors.lastname: Solomon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001485:Basement Membrane / Q000201:enzymology / Q000473:pathology; D004396:Coloring Agents; D003430:Cross-Sectional Studies; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D005260:Female; D006801:Humans; D017676:Lichen Planus, Oral / Q000201:enzymology / Q000209:etiology* / Q000473:pathology; D008297:Male; D008407:Mast Cells / Q000473:pathology; D008875:Middle Aged; D009061:Mouth Mucosa / Q000201:enzymology / Q000473:pathology; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D004396:Coloring Agents; D051546:Cyclooxygenase 2
keywords: COX-2; Cytokines; basement membrane; mast cell; oral lichen planus