Clinical Assistant Professor Texas A&M University College Station, Texas, United States
Abstract:
Background: The enteric nervous system is complex and increasingly recognized in playing a role in gastrointestinal disorders. Previous studies described increased fecal concentration of nervonic acid, a fatty acid abundant in nerve fibers, in dogs with protein-losing enteropathy. However, the enteric nervous system has not been previously investigated in control dogs and dogs with chronic enteropathy (CE).
Objective: Describe and compare the microscopic distribution of nerves in the small intestinal mucosa in dogs with CE and control dogs. Animals: Formalin-fixed paraffin-embedded duodenal samples from 10 control dogs, 14 dogs with CE and hypoalbuminemia (CE-H), and 10 dogs with CE and normalbuminemia (CE-N).
Methods: Retrospective cross-sectional study. Expression of the neural marker protein gene product (PGP) 9.5 was assessed in duodenal samples by immunohistochemistry. The positive area was quantified using QuPath. Kruskal–Wallis and Dunn's tests were used for comparison of expression between groups.
Results: A network of fine nerve fibers was identified in the duodenal mucosa from dogs of all three groups, with nerve fibers frequently surrounding central lacteals within villi. No significant differences in PGP 9.5 protein expression were detected in the villous (median: CE-H 1595, CE-N 1666, control 1749 pixels, P = 0.70) or crypt (median: CE-H 725, CE-N 984, control 611 pixels, P = 0.36) duodenal lamina propria among dogs with CE-H, CE-N, and control dogs. Conclusions and clinical importance: The canine small intestinal mucosa has an extensive nerve network. No evidence of nerve remodeling was identified in the small intestinal mucosa of dogs with CE.
