Expression of midkine and receptor-like protein tyrosine phosphatase (RPTP)-β genes in the rat stomach and the influence of rebamipide

Abstract

Background: Midkine has been reported to bind to receptor-like protein tyrosine phosphatase (RPTP)-β and to play important roles in growth and differentiation of various cells. Midkine is expressed in rat stomach during experimental ulcer healing, suggesting that the midkine-RPTP-β system has some physiological functions in the stomach. Rebamipide is a mucoprotective drug used for the treatment of gastric ulcers. We have tested the hypothesis that the ulcer healing mechanism stimulated by rebamipide is linked physiologically to the gastric midkine-RPTP-β system. Materials and methods: Seven-week-old-male Wistar rats were used. Midkine and RPTP-β gene expression in rat stomach was investigated by laser capture microdissection coupled with the reverse transcription-polymerase chain reaction (RT-PCR). The effects of rebamipide on midkine and RPTP-β expression in rat stomach and the gastric epithelial cell line RGM1 were evaluated by RT-PCR and Northern blot analyses. Results: Midkine and RPTP-β expression was detected in the gastric mucosal, submucosal and muscle layers. Rebamipide stimulated both midkine and RPTP-β expression in rat stomach and RGM1 cells. Conclusion: Rebamipide may protect the gastric mucosa by regulating midkine and RPTP-β expression.