Background:With the development of capsule endoscopy,small intestinal injury induced by non-steroidal anti-inflammatory drugs( NSAIDs)has become an issue of growing concern. Although there are a variety of drugs used for NSAIDs-induced gastric mucosal injury,small intestinal injury caused by NSAIDs is lack of effective prevention and treatment modalities. Aims:To investigate the protective effect and possible mechanism of rebamipide on human colon cancer cell line Caco-2 injury induced by aspirin. Methods:In aspirin group,Caco-2 cells were treated with aspirin 10 mmol/L;in rebamipide group,Caco-2 cells were treated with aspirin and different concentrations of rebamipide(0. 1, 0. 5,1. 0 mmol/L),and a negative control group was established. Cell proliferation inhibition was measured by MTT assay. Cell apoptosis was determined by flow cytometry. Morphological changes of cells were observed under inverted phase contrast microscope. Permeability of cells was assessed by Transwell assay. Expressions of tight junction proteins occludin and zonula occluden-1(ZO-1),as well as mitogen activated protein kinase(MAPK)signaling pathway-associated proteins including extracellular signal-regulated kinase(ERK)1/2,phosphorylated ERK1/2(p-ERK1/2),p38,p-p38,c-Jun N-terminal kinase( JNK),and p-JNK,were determined by Western blotting. Results:Proliferation inhibition rate,apoptosis rate and permeability of Caco-2 cells in rebamipide 0. 1,0. 5,1. 0 mmol/L groups were significantly lower than those in aspirin group in a dose-dependent manner(P<0. 05). Injuries of Caco-2 cells were seen in aspirin group by inverted phase contrast microscope and rebamipide could reduce these injuries. Expressions of occludin,ZO-1 and p-JNK were significantly higher and expressions of p-p38 and p-ERK1/2 were significantly lower in rebamipide 0. 1,0. 5,1. 0 mmol/L groups than those in aspirin group in a dose-dependent manner(P<0. 05). Conclusions:Rebamipide have a protective effect against aspirin-induced Caco-2 cell injury,probably through regulating MAPK signaling pathway( inhibiting p38 and ERK1/2 phosphorylation,stimulating JNK phosphorylation),and subsequently up-regulating the expressions of tight junction proteins and decreasing the permeability of cells.