The effects of cyclo-oxygenase inhibitors on bile-injured and normal equine colon.

This research paper delves into the potential side effects of cyclo-oxygenase (COX) inhibitors, which are nonsteroidal anti-inflammatory drugs (NSAIDs), on horses suffering from colitis. The study specifically examines the nonselective COX inhibitor flunixin and the selective COX-2 inhibitor etodolac, to observe their impact on repair processes in bile-injured colon.

Objective and Hypothesis

• The researchers conducted the study with a prior assumption that the COX inhibitor flunixin, a nonsteroidal anti-inflammatory drug (NSAID), would likely disrupt the healing process of bile-injured colon in horses by hampering the production of prostaglandins which facilitate the repair process.
• They also hypothesized that the COX-2 inhibitor etodolac, a more selective drug, would not hinder the repair process as it preserves COX-1 activity which is responsible for producing necessary prostaglandins.

Methodology

• Experiments were performed on segments of horses’ pelvic flexure that were exposed to deoxycholate, a compound used to induce bile-injury, after which the samples were allowed a recovery period of 4 hours in Ussing chambers, specialized devices used to measure transport and barrier functions of epithelial tissues.

Findings

• The observations from the study refuted the original hypothesis. Recovery of bile-injured colonic mucosa was unaffected by both flunixin and etodolac, even though a notable decline in prostanoid production was recorded.
• However, control tissues treated with flunixin saw a rise in mucosal permeability, while treatment with etodolac had negligible impact.

Conclusion

• The study’s outcomes suggest that recovery from bile-induced colonic injury may not rely on prostanoids produced by COX as was initially hypothesized.
• The research also concludes that treatment involving nonselective COX inhibitors, like flunixin, may lead to a significant increase in permeability of tissues, possibly indicating risky side effects.
• Choose selective COX-2 inhibitors such as etodolac may help reduce potential adverse effects in therapeutic situations requiring NSAID usage in horses.