The Effect of Epidermal Growth Factor on Mucosal Function after Ileal Resection

Abstract

Since epidermal growth factor (EGF) enhances gut mucosal regeneration, the present study was undertaken to evaluate the effect of EGF on brush-border membrane enzyme activity and glutamine uptake in the intestinal remnant following extensive small bowel resection. Twenty-four adult male New Zealand White rabbits were divided into three groups: Group 1 ( n = 12) served as controls. Groups 2 and 3 ( n = 6 each) underwent a 50-60% mid-jejunoileal resection with anastomosis of the remaining intestine, leaving 90 cm between the pylorus and the ileocecal valve. Group 3 rabbits had a subcutaneous osmotic pump implanted to deliver EGF for 7 days at 0.3 μg/kg/hr. Rabbits from Groups 2 and 3 were sacrificed 3 weeks postoperation. Mucosa from the proximal and distal segments of the remaining intestine was analyzed for wet/dry weight, maltase and aminooligopeptidase activity, and glutamine uptake. There was a twofold increase in mucosal dry weight/cm of intestine in rabbits without EGF at 3 weeks (Group 2) and a fourfold increase in those given EGF (Group 3). The maltase enzyme capacity (UEnzyme/rabbit) increased from 37 ± 10 in controls (Group 1) to 167 ± 30 without EGF and 207 ± 30 with EGF. The aminooligopeptidase enzyme capacity (UEnzyme/ rabbit) increased from 55 ± 10 to 147 ± 20 and 226 ± 30 in Groups 1, 2, and 3, respectively. Glutamine uptake capacity (μ M glutamine/min) also increased significantly, from 63 ± 19 in Group 1 to 88 ± 6 without EGF and 162 ± 18 with EGF ( P < 0.001). We conclude that EGF greatly increases mucosal mass and brush-border membrane enzyme activity in the residual small intestine following extensive bowel resection which significantly increases the absorptive and digestive capacity.