Correlative morphometry and morphology of normal equine intestinal mucosa and comparison after adaptation to extensive large colon resection.

The researchers studied the shape and structure of intestinal tissue samples from horses, and compared the results between normal horses and those who had undergone a major colon surgery a year prior. They found that the intestines had different shapes and amounts of certain cells, and the post-surgery horses saw a significant increase in certain areas of their remaining large colon.

Research Methods

• The means of examination used in this study were light microscopy, morphometry and scanning electron microscopy (SEM). The researchers used these techniques to observe the smallest details of the intestinal tissue samples.
• The study was conducted on the intestinal tissues of five horses: two control horses that had not undergone any surgery and three that had a major colon surgery performed on them a year prior. Seven samples were studied, three from the small intestine and four from the large intestine.

Study Findings

• Qualitative and quantitative evaluations of the intestinal tissues revealed that the surgical and control horses had similar morphology. However, the control horses had significantly fewer goblet cells, which produce mucus and are important for nutrient absorption and protection against harmful substances, in their large intestine crypts.
• In the small intestine, Scanning Electron Microscopy showed that the villi, finger-like structures that increase the internal surface area of the intestinal walls, varied in shape from coned to broad and flat.
• In the large intestine, the crypt openings, tube-like structures between the villi, were more prominent in the right ventral and dorsal colon compared to the caecum. The most prominent crypt openings with the least variation were found in the small colon.
• Morphometric evaluation indicated that in the small intestine, there were more goblet cells present and the enterocytes, cells that line the intestine, were slimmer. This applied specifically in the area stretching from the cranial jejunum to the ileum.
• In contrast, in the large intestine, the area and depth of the crypts increased significantly while the space in-between the crypts decreased. This finding was most noted in an aboral (opposite the direction of the mouth) direction from the caecum to the small colon.

Post-Surgery Findings

• The research also looked at the intestinal tissues of horses which had undergone extensive large colon resection surgery a year before. In comparison to control horses, these post-surgery horses had a significantly larger intercrypt area in the caecum and remaining large colon. This suggests that the resection surgery influenced the intestinal morphology of these horses.