Fluoro-loxoprofen (F-LOX), which is a derivative of loxoprofen (LOX), has been reported to be less ulcerogenic response to the gastric mucosa, but its effect on the small intestinal mucosa has not been investigated. In this study, we investigated the influence of the novel anti-inflammatory drug F-LOX on the small intestine in rats.
F-LOX and LOX were orally administered to male SD rats, and the total area of macroscopic injury in the small intestine was determined 24 h later. The prostaglandin E2 (PGE2) production and cAMP contents in the small intestine were examined 3 or 6 h after administration of drugs by enzyme immunoassay.
LOX caused hemorrhagic injury along the small intestine, mainly in the jejunum and ileum 24 h later. The intestinal lesion was also observed in the F-LOX group, but it was less, and the severity was lower than in the LOX group. The PGE2 production in the small intestine was significantly decreased 3 h after LOX and F-LOX administration. The cAMP contents were significantly reduced in the LOX group but not in F-LOX group. A decrease in PAS-positive mucus was observed in the F-LOX group, but the amount of mucus was higher than that in the LOX group. In conclusion, F-LOX is an NSAID that has the same anti-inflammatory effect as LOX but is less damaging to the small intestinal mucosa.