Manganese superoxide dismutase (MnSOD) is known to protect oxygen-utilizing cells from the toxicity of the reactive oxygen species and evidence has shown that decreased MnSOD expression has been observed in both reflux esophagitis and Barrett’s Esophagus (BE). Thus, the aim of this study is to investigate the role of MnSOD expression and activity in the development of BE. Methods:Our established novel external esophageal perfusion animal model perfused 0.5% bovine bile, pH 7.4 in rats along with saline perfusion for 1, 2, and 4 weeks. The esophageal mucosal was isolated for MnSOD expression by Western blot and activity of SOD was evaluated by Xanthine Oxidase-Cytochrome C Assay. Results: Severe esophagitis was observed at both 1 and 2 week perfusion, with BE being identified at 4 weeks with glandular structures consistent with columnar cells appearing in the submucosa by HE staining. A significant deceased of MnSOD expression with bile perfusion was demonstrated by computer imaged analyzed staining of both Western blot (p=0.01) and immunohistochical evaluation (Figure). Similarly, MnSOD enzyme activity but not copper/zinc SOD enzyme activity was significantly decreased in bile perfused esophageal mucosal tissues when related to the saline controls and the standard. Conclusions: MnSOD expression and activity is significantly decreased in bile induced esophagitis. This loss of MnSOD expression leads to the decreased total SOD activity, which might contributes to the metaplastic changes of BE.

MnSOD expression by Western Blot (above) and enzyme activity for standard(St), normal(NE) compared to bile perfusion (PAR2) (below).