Increased microvascular permeability in early stage of dextran sulfate sodium-induced colitis: Its interaction with lansoprazole binding sites

To clarify the microvascular changes and the effector sites of lansoprazole during the formation of colitis, the dextran sulfate sodium (DSS)-induced colitis was induced by the oral administration for 3 and 7 days. The alteration of the microvascular permeability was estimated by the intraaortic infusion of FITC-dextran. The effector sites of ³H-lansoprazole were examined by the intraaortic infusion of the radiolabelled compound and the autoradiographic procedure of water-soluble compounds. As a result, marked increase of the microvascular permeability was detected three days after DSS treatment near the inflammatory cells in the tip portion of the colonic mucosa. ³H-lansoprazole in the control rat colon was localized in the goblet cells, while in DSS-treated rats, ³H-lansoprazole was accumulated in the cytoplasm of the mesenchymal cells, and most of them coincided with polymorphonuclear leucocytes and macrophages.