Induction of peritoneal adhesions with small intestinal ischaemia and distention in the foal.

The research investigates methods for inducing peritoneal adhesions in foals by using intestinal distension and ischaemia. It aims to understand the resulting tissue changes post-surgery, and how age affects these changes in foals.

Research Methodology

• The researchers conducted an experiment involving twenty-two foals, categorising them into groups based on the method used to induce peritoneal adhesions: intestinal distension and intestinal ischaemia.
• In the intestinal distension group, occlusion was induced in a segment of the distal small intestine. This was accomplished without affecting vascular supply and by distending it with lactated Ringer’s solution. The resulting pressure was maintained at 25 cm of H₂O for a span of two hours inside the abdomen.
• In the intestinal ischaemia group, an identical segment of the bowel was subjected to a total vascular occlusion for seventy minutes.
• Serosal biopsies were taken before and after each experimental procedure, as well as after sixty minutes of reperfusion.
• A control group of foals, with no bowel occlusions, had similar biopsies taken.
• The foals were euthanized ten days following the procedures and various tissues were collected to be analyzed histologically and ultrastructurally.

Results and Observations

• It was observed that both the experimental and control mesothelial surfaces were histologically denuded immediately after the occlusions.
• Serosal oedema and cellular infiltration became evident after the reperfusion of the ischaemic segments, but these were immediately present in cases where there had been two hours of distension.
• All foals developed bowel-to-bowel and bowel-to-mesentery adhesions at the site of the experimental segments.
• The mesentery from the control group of foals less than 30 days old showed contractions and thickening of the isolated segment, whereas older foals had negligible mesenteric thickening or contractions.
• From a histological perspective, in the experimental segments, a formation of fibrous tissue was identified on the outer limits of the original serosa. Newly formed cells resembling mesothelial cells were found on certain areas of the fibrous tissue covering.
• In the control segments, most showed some level of serosal fibrosis.