Lansoprazole prevents experimental gastric injury induced by non-steroidal anti-inflammatory drugs through a reduction of mucosal oxidative damage

AIM: This study investigated the mechanisms of protection afforded by the proton pump inhibitor lansoprazole against gastric injury induced by different non-steroidal anti-inflammatory drugs (NSAIDs) in rats. METHODS: Male Sprague-Dawley rats were orally treated with indomethacin (100 mu mol/kg), diclofenac (60 mu mol/kg), piroxicam (150 mu mol/kg) or ketoprofen (150 mu mol/kg). Thirty minutes before NSAIDs, animals were orally treated with lansoprazole 18 or 90 mu mol/kg. Four hours after the end of treatments, the following parameters were assessed: gastric mucosal PGE2, malondialdehyde (MDA), myeloperoxidase (MPO) or non-proteic sulfhydryl compounds (GSH) levels; reverse transcription-polymerase chain reaction (RT-PCR) of mucosal COX-2 mRNA; gastric acid secretion in pylorus-ligated animals; in vitro effects of lansoprazole (1-300 mu mol/L) on the oxidation of low density lipoproteins (LDLs) induced by copper sulphate. RESULTS: All NSAIDs elicited mucosal necrotic lesions which were associated with neutrophil infiltration and reduction of PGE2 levels. Increments of MPO and MDA contents, as well as a decrease in GSH levels were detected in the gastric mucosa of indomethacin-or piroxicam-treated animals. Indomethacin enhanced mucosal cyclooxygenase-2 expression, while not affecting cyclooxygenase-1. At the oral dose of 18 mu mol/kg lansoprazole partly counteracted diclofenac-induced mucosal damage, whereas at 90 mu mol/kg it markedly prevented injuries evoked by all test NSAIDs. Lansoprazole at 90 mu mol/kg reversed also the effects of NSAIDs on MPO, MDA and GSH mucosal contents, without interfering with the decrease in PGE2 levels or indomethacin-induced cyclooxygenase-2 expression. However, both lansoprazole doses markedly inhibited acid secretion in pylorus-ligated rats. Lansoprazole concentration-dependently reduced the oxidation of LDLs in vitro. CONCLUSION: These results suggest that, besides the inhibition of acid secretion, lansoprazole protection against NSAID-induced gastric damage depends on a reduction in mucosal oxidative injury, which is also responsible for an increment of sulfhydryl radical bioavailability. It is also suggested that lansoprazole does not influence the downregulation of gastric prostaglandin production associated with NSAID treatment. (C) 2005 The WJG Press and Elsevier Inc. All rights reserved.