Adaptation after small bowel resection is attenuated by sialoadenectomy: the role for endogenous epidermal growth factor.

Background: Epidermal growth factor (EGF) is likely involved during adaptation after small bowel resection (SBR) because some studies have shown enhanced adaptation by EGF administration. Because the major source of endogenous EGF in mice is the submandibular glands, we sought to determine the effect of submandibular gland excision (SAL) and luminal or systemic EGF replacement on adaptation after SBR.

Methods: A 50% proximal SBR or Sham-SBR (bowel transection and reanastomosis) was performed on male C57BL/6 mice after either SAL or gland mobilization only. Additional mice underwent both SBR and SAL and then received daily EGF or saline solution by intraperitoneal or orogastric administration. At 1 week, adaptation was characterized in the ileum as changes in villus height, DNA, and protein content.

Results: SAL significantly attenuated the increase in ileal villus height, total protein, and DNA content after SBR. Both systemic and oral EGF reversed these findings equally and significantly augmented all parameters of intestinal adaptation after SAL.

Conclusions: Submandibular EGF is important for the adaptive response to massive SBR. As both luminal and systemic EGF equally reversed the findings following SAL and SBR, the specific site of action for endogenous EGF during adaptation is either the luminal or basolateral surface of the enterocyte.