Effects of phenylbutazone, indomethacin, prostaglandin E₂, butyrate, and glutamine on restitution of oxidant-injured right dorsal colon of horses in vitro

Objective - To study the effects of phenylbutazone, indomethacin, prostaglandin E₂ (PGE₂), glutamine, and butyrate on restitution of oxidant-injured right dorsal colon of horses in vitro. Sample Population - Right dorsal colon from 9 adult horses euthanatized for reasons other than gastrointestinal tract disease. Procedures - Mucosal segments from the right dorsal colon were injured via exposure to HOCI and incubated in Ussing chambers in solutions containing phenylbutazone, indomethacin, indomethacin and PGE₂, glutamine, and butyrate. Transepithelial resistance and mucosal permeability to mannitol were measured, and all mucosal segments were examined histologically. Results - The HOCI-injured mucosa had lower resistance and higher permeability to mannitol, compared with control tissue. Histologic changes were also evident. Resistance of HOCI-injured mucosa recovered partially during the incubation period, and glutamine improved recovery. Phenylbutazone and indomethacin increased resistance, but these increases were not significant. Butyrate and PGE₂ had no effects, compared with nontreated HOCI-injured tissues. Mucosal permeability to mannitol was lower in glutamine-treated tissue, compared with nontreated tissue. Histologic changes reflected the resistance and permeability changes. Conclusions and Clinical Relevance - According to our findings, phenylbutazone and indomethacin do not seem to interfere with restitution of oxidant-injured mucosa of equine colon in vitro, and glutamine could facilitate mucosal restitution.