Protection of the rat gastric mucosa against aspirin injury by arachidonic acid: a dietary prostaglandin precursor fatty acid

We studied aspirin-induced injury to the gastric mucosa in control rats pretreated with a solubilizer, pluronic F-68 (PL), and in rats pretreated with solubilized arachidonic acid (AA). Fasted male rats were pretreated intragastrically with 1 ml of either pluronic or AA and 1 h later acidified ASA (1 ml suspension of 200 mg kg-1 body weight) was administered intragastrically. Grossly apparent mucosal lesions developed 1 h after aspirin in pluronic-pretreated rats, but were significantly reduced in AA-pretreated rats. Histology, scanning and transmission electron microscopy demonstrated that AA pretreatment did not prevent aspirin-induced initial damage to the surface epithelium but did significantly reduce extent of aspirin-induced deep mucosal necrosis at 1, 4 and 18 h after aspirin. Initial aspirin-induced surface epithelial damage was rapidly restituted by two distinct types of re-epithelialization - vertical and horizontal. While the vertical type of re-epithelialization has been reported previously as the first stage of mucosal repair following injury by various noxious agents such as concentrated ethanol, the horizontal type of re-epithelialization, which is described for the first time in this paper, seems to be specific for the repair of aspirin-induced gastric mucosal injury. These studies suggest that dietary factors such as essential fatty acids may play a role in gastric mucosal protection against aspirin injury.