In vitro and in vivo protection against indomethacin-induced small intestinal injury by proton pump inhibitors, acid pump antagonists, or indomethacin-phosphatidylcholine

Abstract

Background/aims: Proton pump inhibitors (PPIs) are widely used to prevent nonsteroidal anti-inflammatory drug (NSAID)-induced peptic ulcers. NSAIDs produce small intestinal injury and some PPIs have been reported to protect against NSAID-induced small bowel injury in rats. The aim of this study was to compare PPIs, revaprazan, and phosphatidylcholine-associated indomethacin (Indo-PC) for protection against indomethacin (Indo)-induced small bowel injury.

Methods: Rat intestinal epithelial cells (IEC-6) were pretreated with omeprazole, lansoprazole, or revaprazan prior to exposure to Indo or Indo-PC. Cell viability was assessed by methyl thiazolyl tetrazolium assay. Omeprazole, lansoprazole, or revaprazan was administered orally to rats prior to the vehicle or Indo. Indo-PC was administered alone. After 24 h, small intestinal erosions were counted; intestinal bleeding was assessed as the hemoglobin concentration of small intestinal fluid.

Results: Omeprazole, lansoprazole, and revaprazan did not protect against Indo-induced IEC-6 cell injury. Indo-PC was less damaging in vitro than Indo alone. In vivo, neither omeprazole nor lansoprazole protected against Indo-induced small bowel injury; however, revaprazan pretreatment and Indo-PC resulted in significantly fewer erosions (>50% reduction) or bleeding (>80% reduction).

Conclusion: PPIs showed no small bowel protective effect in vitro or in vivo. Revaprazan showed a small bowel protective effect in vivo, whereas Indo-PC was protective both in vitro and in vivo.

Figure 1

In vitro studies - Indo. (A) MTT assay showed that indomethacin decreased cell viability in a dose-dependent manner. (B) MTT assay showed that omeprazole, lansoprazole and revaprazan did not reverse the Indomethacin-induced reduction in intestinal cell viability.

Figure 2

In vitro studies – Indo-PC. (A) MTT assay showed Indo-PC at 1mM was less injurious than Indo alone. (B) Caspase-3/7 assay showed that Indo-PC induced less apoptosis than Indo alone. *=p<0.001 versus Control; #=p<0.001 versus Indo.

Figure 3

In vivo studies – lesions. (A) A 10 mg/kg dose of indomethacin produced punctate hemorrhagic spots and small punch-out lesions on the small intestine in rats. (B) Small intestinal lesion scores. Omeprazole and lansoprazole pretreatment did not alter the indomethacin-induced mucosal lesion score, while revaprazan pretreatment tended to reduce the lesion score (p=0.06). Indo-PC showed significantly fewer gross small intestine mucosal lesions than Indomethacin alone (p<0.05)*.

Figure 4

In vivo studies – bleeding. Intestinal fluid hemoglobin assay. Revaprazan-pretreatment group and Indomethacin-phosphatidylcholine (Indo-PC)-group had statistically significant decreased hemoglobin levels of the collected intestinal fluid compared to indomethacin alone (p<0.05)*. In contrast, omeprazole and lansoprazole did not reduce intestinal bleeding induced by indomethacin.