title: Inducible nitric oxide expression correlates with the level of inflammation in periapical cysts.
abstract: OBJECTIVE
  In an attempt to elucidate if inducible nitric oxide expression (iNOS) is correlated with the level of inflammation in periapical cysts with accuracy, the goal of this study was to evaluate the expression of iNOS in these ones.
  
  
  METHODS
  30 cases were included in this study being iNOS evaluated by means of immunohistochemistry. Statistical analysis was performed by Kruskal-Wallis non-parametric test followed by the post-hoc Dunn's test.
  
  
  RESULTS
  iNOS stain was detected throughout the epithelium, subepithelial fibroblasts and macrophages in all cases, indistinctly. Nevertheless, iNOS immunostaining in periapical cysts was different according to the levels of inflammation, being the strongest effect associated with intense inflammatory infiltrate.
  
  
  CONCLUSIONS
  Taken together, our results indicate that immunoreactivity of iNOS was expressed in several cellular types present in periapical cyst, being positively correlated with the level of inflammation. Therefore, iNOS expression plays an important role in the pathogenesis of periapical cysts.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University of Sacred Heart, USC, Bauru, SP, Brazil.
authors.forename: Mariza Akemi
authors.initials: MA
authors.lastname: Matsumoto
authors.forename: Daniel Araki
authors.initials: DA
authors.lastname: Ribeiro