Experimental small bowel obstruction in chick embryos: Effects on the developing enteric nervous system

Area of Science:

• Developmental biology
• Neuroscience
• Gastroenterology

Background:

• Congenital small bowel atresias often lead to intestinal motility disorders post-surgical repair.
• These motility issues may stem from alterations in the enteric nervous system (ENS) due to intestinal obstruction.

Purpose of the Study:

• To investigate the structural changes in the ENS following experimentally induced small bowel atresias in chick embryos.
• To correlate these ENS changes with potential causes of motility disorders observed after surgical repair of intestinal atresias.

Main Methods:

• Small bowel atresias were surgically induced in 90 chicken embryos on day 11 via microsurgical ligation.
• Histological analysis included silver-staining, semithin serial sections, transmission electron microscopy, and acetylcholinesterase (AChE) staining.
• Normal chick embryos of the same age served as controls for comparison.

Main Results:

• Experimentally induced atresias mimicked human congenital small bowel atresias macroscopically.
• Microscopically, the submucosal plexus was nearly absent both proximally and distally to the obstruction.
• The myenteric plexus was reduced in the proximal dilated segment, with disrupted axonal nets and altered ganglion cell clustering. Cells of Cajal were absent.

Conclusions:

• Structural changes in the ENS were observed secondary to experimentally induced small bowel atresias.
• Proximal gut dilatation, not ischemia, appears to be the primary driver of these ENS alterations.
• These findings provide a potential explanation for motility disorders following surgical repair of intestinal atresias, anorectal malformations, and Hirschsprung's disease.