Purpose: Nonsteroidal anti-inflammatory drugs (NSAIDs) often cause ulcers in the small intestine in humans, but there are few effective agents for treatment of small intestinal ulcers. We found that soluble dietary fibers (SDFs), such as pectin, could prevent the formation of small intestinal lesions induced by indomethacin (IND) in cats. To elucidate the mechanism of protection by SDFs, we examined the viscosities of SDFs and the effects of pectin on gastrointestinal absorption of IND and intestinal hypermotility induced by IND.
Methods: Cats were given regular dry food (RFD-Dry) or RFD-Dry supplemented with pectin, guar gum, polydextrose, or mucin twice daily. IND was administered orally once daily for 3 days. Mucosal lesions in the small intestine were examined 24 h after the final dosing of IND. Plasma concentrations of IND were measured by HPLC. GI motilities were measured using a telemetry system in conscious cats implanted with force transducers. Viscosities of the SDFs were measured using a viscosimeter.
Results: In cats given RFD-Dry, IND (3 mg/kg) increased motility and produced many lesions in the lower half of the small intestine; the total lesion area (TLA) was 7.5 +/- 2.6 cm(2) (n = 4). Lesions induced by IND were markedly decreased in cats given RFD-Dry supplemented with 3% pectin, guar gum, polydextrose or mucin; TLAs were 0.6 +/- 0.3, 0.0 +/- 0.0, 1.3 +/- 0.8 and 1.6 +/- 0.5 cm(2) (n = 4) (P < 0.05 vs. RFD-Dry alone), respectively. The viscosity (mPa-S) of pectin, guar gum, polydextrose and mucin (3% concentration) was 414, >1,200, 1 and 4, respectively. Pectin did not affect the absorption of IND nor did it inhibit IND-induced intestinal hypermotility.
Conclusions: SDFs protect the small intestine against NSAID-induced damage, probably by compensating a barrier function of the mucin decreased by IND. Viscosities of the SDFs play a role, at least in part, in the protective effects of the SDFs on the small intestine.