A morphological and quantitative immunohistochemical study of the interstitial cells of Cajal in the normal equine intestinal tracts.
BACKGROUND
The interstitial cells of Cajal (ICC) play a key role in the control of intestinal motility and have been implicated in several human gastrointestinal dysmotility syndromes, in equine grass sickness and in other intestinal disorders where a significant reduction in ICC density was observed.


OBJECTIVE
To investigate the density of ICC in clinically normal horses, ICC c-Kit expression was evaluated by image analysis in order to obtain numerical data.


METHODS
Intestinal samples from the jejunum to small colon from 5 clinically normal horses were studied. Immunohistochemical labelling of ICC was performed using an anti-c-Kit antibody. Density of ICC was calculated using image analysis software.


RESULTS
In the equine intestinal tract 2 types of ICC were observed: intramuscular ICC, i.e. ICC in the internal circular layer (IC-CM) and ICC in the external longitudinal layer (IC-LM), and myenteric ICC (IC-MY). The density of IC-MY was found to be higher throughout the small intestine. IC-MY density in the large intestine appeared to be greatest in the right ventral colon and in the small colon. IC-MY density in the ileocaecal junction showed an intermediate value compared to the small and large intestine. On the other hand, the density of IC-CM was found to be higher in the ileocaecal junction, whereas the caecum, left ventral colon and the left dorsal colon showed the lowest c-Kit immunoreactivity. The ileal tract and the ileocaecal junction showed an appreciable IC-LM density.


CONCLUSIONS
Image analysis is a rapid and reproducible method to establish the density of ICC in the normal equine intestinal tract.


CONCLUSIONS
This study corroborates the findings of previous studies and provides a platform for further future pathological investigations of the equine intestine by supplying usable numerical data as comparative elements.
Department of Biopathological Science and Hygiene of Animal and Food Productions, Veterinary Medicine Faculty, University of Perugia, Via S. Costanzo 4, 06126 Perugia, Italy.
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Pavone
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Mandara
D000818:Animals; D005260:Female; D006736:Horses; D056885:Interstitial Cells of Cajal / Q000166:cytology* / Q000502:physiology*; D007422:Intestines / Q000166:cytology*; D008297:Male