Mucus reduction promotes acetyl salicylic acid-induced small intestinal mucosal injury in rats

Acetyl salicylic acid (ASA) is a useful drug for the secondary prevention of cerebro-cardiovascular diseases, but it has adverse effects on the small intestinal mucosa. The pathogenesis and prophylaxis of ASA-induced small intestinal injury remain unclear. In this study, we focused on the intestinal mucus, as the gastrointestinal tract is covered by mucus, which exhibits protective effects against various gastrointestinal diseases. ASA was injected into the duodenum of rats, and small intestinal mucosal injury was evaluated using Evans blue dye. To investigate the importance of mucus, Polysorbate 80 (P80), an emulsifier, was used before ASA injection. In addition, rebamipide, a mucus secretion inducer in the small intestine, was used to suppress mucus reduction in the small intestine of P80-administered rats. The addition of P80 reduced the mucus and exacerbated the ASA-induced small intestinal mucosal injury. Rebamipide significantly suppressed P80-reduced small intestinal mucus and P80-increased intestinal mucosal lesions in ASA-injected rats, demonstrating that mucus is important for the protection against ASA-induced small intestinal mucosal injury. These results provide new insight into the mechanism of ASA-induced small intestinal mucosal injury. Mucus secretion-increasing therapy might be useful in preventing ASA-induced small intestinal mucosal injury. •Mucus reduction promoted ASA-induced small intestinal mucosal injury.•Addition of P80 reduced the mucus and exacerbated the ASA-induced mucosal injury.•Rebamipide significantly suppressed P80-reduced small intestinal mucus.