Epidermal Growth Factor Receptor Expression Following Small Bowel Resection

Abstract

Background: Adaptation following massive small bowel resection (SBR) is an important compensatory response. While epidermal growth factor (EGF) has been shown to augment this response, the mechanism and role of EGF and its intestinal receptor (EGF-R) during adaptation are not known. The purpose of this study was to determine the effect of massive SBR and adaptation on intestinal expression of EGF-R. Materials and methods: Male Sprague–Dawley rats underwent either a 75% mid-SBR with primary reanastomosis or sham operation (bowel transection with reanastomosis). Ileal mucosa was harvested from animals of each group at 6 and 12 hr, 1, 3, and 5 days, and 1, 2, and 4 weeks after operation. Expression of EGF-R protein was studied by Western blotting. Expression of EGF-R mRNA was determined by quantitative reverse-transcriptase polymerase chain reactions normalized to β-actin. Results: When compared with sham, SBR resulted in a modest (32%) increase in the expression of EGF-R mRNA at 1 week (P< 0.003). A twofold greater expression of EGF-R protein corresponded to this time point. While not statistically significant, expression of EGF-R mRNA was slightly greater after SBR at every other time point measured. Conclusion: Following massive SBR, expression of both EGF-R mRNA and protein is slightly increased in the ileum with a more pronounced increase in protein. These findings, which have not previously been reported, suggest that changes in EGF-R signaling may not play a major role during the initiation and or progression of intestinal adaptation following massive SBR.