Serosal injury in the equine jejunum and ascending colon after ischemia-reperfusion or intraluminal distention and decompression.
Authors: Dabareiner R M, Sullins K E, White N A, Snyder J R
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Serosal Injury in Equine Intestine Ischaemic-reperfusion injury and over-distention remain significant concerns in equine colic surgery, yet the precise mechanisms of tissue damage across different intestinal segments remain incompletely understood. Dabareiner and colleagues experimentally induced ischaemia (70 minutes) followed by reperfusion (60 minutes) in both jejunal and colonic segments in seven horses, whilst separately creating controlled intraluminal distention (25 cm H₂O for 120 minutes) in jejunal loops, taking seromuscular biopsies at multiple timepoints and examining them under light, transmission electron and scanning electron microscopy. The jejunum demonstrated severe morphological changes to the serosal and muscular layers following both injury models, whereas identical ischaemic-reperfusion protocols caused only minimal damage to the ascending colon serosa—a striking differential tissue response that suggests the small intestine's greater vulnerability to both ischaemic and mechanical insults. These findings have important implications for surgical decision-making: the relative resilience of colonic tissue may justify more conservative approaches to large colon lesions, whilst jejunal segments sustaining significant ischaemia or distention warrant more guarded prognoses and perhaps lower thresholds for resection. Understanding these tissue-specific responses helps practitioners better counsel owners on post-operative complications and guides judgement regarding which compromised segments are likely to recover function versus those destined for adhesion formation or stricture.
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Practical Takeaways
- •Jejunal segments have poorer tolerance for ischemia and mechanical distention compared to large colon—prognosis and tissue viability assessment may differ between small and large intestinal lesions during colic surgery.
- •Even brief periods of intestinal distention can cause irreversible serosal damage; this supports aggressive decompression protocols in impaction or obstruction cases.
- •Post-operative adhesion risk and peritonitis risk may be higher after jejunal compromise than colonic compromise due to greater serosal damage, affecting post-operative monitoring intensity.
Key Findings
- •Equine jejunum sustained severe serosal and muscular layer damage after 70 minutes of ischemia followed by 60 minutes of reperfusion, while ascending colon showed minimal changes from identical ischemia-reperfusion protocol.
- •Intraluminal distention at 25 cm H₂O for 120 minutes followed by 120 minutes of decompression caused significant serosal damage in jejunum comparable to ischemia-reperfusion injury.
- •Small intestine is substantially more susceptible to seromuscular layer injury than large colon under equivalent ischemic or mechanical stress conditions.