Myeloperoxidase activity of the large intestine in an equine model of acute colitis

Objective-To determine whether quantification of myeloperoxidase (MPO) acti vity could be a useful laboratory technique to detect granulocyte infiltrat ion in equine intestinal tissues. Sample Population-Intestinal tissue (inflamed or healthy) collected from 16 age- and sex-matched Shetland Ponies. Procedure-Intestinal tissue MPO activity was determined, and histologic ass essment of adjacent specimens from healthy and inflamed intestine was done. Results-Intestinal tissue MPO activity and histopathologic score increased with time after castor oil challenge and peaked at 16 hours in an equine di arrhea model in which individual ponies provided their own control tissues. Conclusions-Intestinal tissue inflammation scores correlated positively wit h tissue MPO activity in adjacent specimens. Clinical Relevance-Tissue MPO assay may be a useful laboratory tool to quan tify intestinal mucosal inflammation in ponies.