Aggravation of inflammatory bowel disease by cyclooxygenase-2 inhibitors in rats

Area of Science:

• Gastroenterology
• Inflammation research
• Pharmacology

Background:

• Dextran sodium sulfate (DSS) is commonly used to induce experimental colitis in rodents.
• Cyclooxygenase-2 (COX-2) is an enzyme involved in prostaglandin synthesis, implicated in inflammation.
• The role of COX-2 in distal colon inflammation and ulceration requires further elucidation.

Purpose of the Study:

• To investigate the in-vivo effect of a selective COX-2 inhibitor on DSS-induced colitis in rat distal colon.
• To assess the impact of celecoxib on inflammatory markers, oxidative stress, and prostaglandin E2 (PGE2) levels in the colon.

Main Methods:

• Rats were treated with DSS to induce colitis.
• Animals were pretreated with celecoxib, a selective COX-2 inhibitor.
• Colon tissues were analyzed for inflammation, altered contraction, myeloperoxidase activity, oxidative stress, and PGE2 levels.

Main Results:

• DSS-induced colitis resulted in significant inflammation, altered contraction, increased myeloperoxidase activity, and oxidative stress.
• Celecoxib pretreatment exacerbated all measured parameters of colon inflammation.
• Chronic celecoxib administration led to reduced PGE2 levels in DSS-treated rats.

Conclusions:

• COX-2 and its derived prostaglandins appear to play a protective role in preventing colon ulceration.
• Selective COX-2 inhibition may worsen DSS-induced colitis, suggesting a beneficial role for COX-2 in this model.
• Findings suggest a potential therapeutic window for COX-2 modulation in colonic diseases, distinct from its role in the upper GI tract.