Effects of Lansoprazole on Ethanol-Induced Injury and PG Synthetic Activity in Rat Gastric Mucosa

Lansoprazole, a proton pump inhibitor, has been reported to inhibit ethanol-induced injury in rats. However, the mechanism of the protective effect is not known. This study was carried out to investigate the role of prostaglandin (PG) in the protective effect of lansoprazole. Male Wistar rats were given either 30 mg/kg of lansoprazole or vehicle alone intragastrically 30 min before administration of ethanol. They were killed to measure the gross mucosal lesions in the stomach as the ulcer index. In another experiment, 5 mg/kg of indomethacin was injected 30 min before administration of lansoprazole. The effects of 16,16-dimethyl PGE2 (dmPGE2) on ethanol-induced injury over time were compared with lansoprazole. PGE2 synthesis in gastric mucosa after administration of lansoprazole was measured by radioimmunoassay. Lansoprazole reduced gastric mucosal injury by lansoprazole. DmPGE2 significantly reduced gastric mucosal injury from 5 min after exposure to ethanol. Lansoprazole did not affect PGE2 synthesis in the gastric mucosa. These results suggest that PG may not be involved in the protective effect of lansoprazole.