A mechanism for prostaglandin cytoprotection

Area of Science:

• Gastroenterology
• Pharmacology

Background:

• Topical 16,16-dimethyl prostaglandin E2 (dm PGE2) induces alkaline secretion in the canine stomach.
• The potential cytoprotective role of this prostaglandin-induced secretion requires investigation.

Purpose of the Study:

• To assess if prostaglandin-induced alkaline secretion plays a cytoprotective role in the canine stomach.
• To determine if eliminating this secretion with counterpressure affects prostaglandin's protective action.

Main Methods:

• Canine stomach wedges were perfused ex vivo, with control and test sides.
• Sequential exposure to acid, dm PGE2, aspirin plus dm PGE2, and acid was performed.
• Pneumatic counterpressure was applied to the test side to reduce fluid movement during aspirin exposure.

Main Results:

• Topical prostaglandin increased transmucosal fluid movement; counterpressure reduced this by 50% and mucosal blood flow by 20%.
• Mucosal lesions were significantly worse on the counterpressure side (2.0 +/- 0.6) compared to the control side (0.8 +/- 0.3).
• Increased damage in the counterpressure group may be due to reduced fluid movement, blood flow, or both.

Conclusions:

• Prostaglandin-induced alkaline secretion appears to have a cytoprotective role in the canine stomach.
• Eliminating this secretion through counterpressure diminishes the protective effect against mucosal damage.
• Further research is needed to differentiate the roles of fluid movement and blood flow in this protective mechanism.