Detection of apoptotic cells in horses with and without gastrointestinal disease.

Abstract

A study was performed to identify apoptotic cells in the equine intestine and to determine if the occurrence of apoptosis is affected by gastrointestinal disease and tissue layer of intestine. Samples of intestine were collected from 38 horses that underwent surgery or were humanely destroyed for small or large bowel obstruction, strangulation or distension. Samples were also taken from 9 horses which were humanely euthanized for reasons other than gastrointestinal disease or systemic disease. Specimens were collected at surgery from intestine involved in the primary lesion, distant to the primary lesion, or at necropsy from several sites including the primary lesion. Tissues were fixed, serially sectioned and stained with hematoxylin and eosin (H&E) and for apoptosis by the terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) technique. The number of apoptotic cells per high power field were counted in the mucosa, circular muscle, longitudinal muscle and serosa for each sample of intestine. Apoptotic staining nuclei were seen in all layers of intestine. An increased number of apoptotic cells were found in the circular muscle of the intestine from horses with simple obstruction. Intestine distant from the primary strangulating lesion had higher numbers of apoptotic cells than intestine distant from a simple obstruction lesion or intestine taken at the site of a strangulating or simple obstructive lesion. Intestine from horses with obstructing or strangulating lesions in the small intestine and large colon has increased numbers of apoptotic cells. Further investigation is required to determine whether increased apoptosis affects intestinal function.