title: Gastroduodenal reflux induces group IIa secretory phospholipase A(2) expression and activity in murine esophagus.
abstract: Exposure of esophageal epithelium to gastric and duodenal contents results in the histologic changes of hyperproliferation and mucosal thickening. We have previously shown that presence of secretory phospholipase A(2) (sPLA(2)) is necessary to produce these histologic changes in a murine model of gastroduodenal reflux. We sought to determine the influence of gastroduodenal reflux (GDR) on sPLA(2) protein and mRNA levels as well as enzyme activity in esophageal tissue. BALB/c (sPLA(2)(+/+)) mice (n= 28) underwent side-to-side surgical anastomosis of the first portion of the duodenum and GE junction (DGEA) resulting in continuous exposure of esophageal mucosa to mixed gastric and duodenal contents. Sham control mice (n= 14) underwent laparotomy, esophagotomy and closure. Real-time RT PCR was used to quantitate the influence of GDR on group IIa sPLA(2) expression. Immunofluorescent staining was quantitated by digital microscopy using a specific antibody to identify and locate sPLA(2) protein. A colorimetric assay was used to quantify total sPLA(2) activity after standardization of protein levels. Statistical analysis was conducted using Student's t-test. Group IIa sPLA(2) mRNA and protein levels were increased at 4 and 8 weeks compared with sham controls. This increase occurred in a time-dependent manner and correlated with esophageal mucosal thickness. Furthermore, sPLA(2) enzyme activity was increased significantly at 4 and 8 weeks compared with untreated controls. The expression of group IIa sPLA(2) as well as sPLA(2) activity is induced by GDR. This novel finding indicates that sPLA(2) may play a role in the development of the histologic changes produced by GDR in esophageal mucosa.
authors.affiliation: Department of Surgery, Division of Cardiothoracic Surgery, University of Colorado at Denver and Health Sciences Center, Denver, Colorado, USA.
authors.forename: David
authors.initials: D
authors.lastname: Mauchley
authors.forename: Xianzhong
authors.initials: X
authors.lastname: Meng
authors.forename: Ashok
authors.initials: A
authors.lastname: Babu
authors.forename: Fabia
authors.initials: F
authors.lastname: Gamboni-Robertson
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Yang
authors.forename: Anirban
authors.initials: A
authors.lastname: Banerjee
authors.forename: David A
authors.initials: DA
authors.lastname: Fullerton
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Weyant
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004942:Esophagitis, Peptic / Q000201:enzymology* / Q000473:pathology; D004947:Esophagus / Q000201:enzymology* / Q000473:pathology; D005455:Fluorescent Antibody Technique; D005764:Gastroesophageal Reflux / Q000201:enzymology* / Q000473:pathology; D054501:Group II Phospholipases A2 / Q000235:genetics / Q000378:metabolism*; D006965:Hyperplasia / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009092:Mucous Membrane / Q000201:enzymology / Q000473:pathology; D012333:RNA, Messenger; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D012333:RNA, Messenger; D054501:Group II Phospholipases A2