Melibiose, difructose anhydride III and difructose anhydride IV enhance net calcium absorption in rat small and large intestinal epithelium by increasing the passage of tight junctions in vitro

An Ussing chamber technique was used to determine the effects of three indigestible disaccharides on net Ca transport from the luminal side to the basolateral side of isolated preparations of jejunal, ileal, cecal and colonic epithelium in rats. Permeability of Lucifer Yellow (LY) and transepithelial electrical resistance (TEER), which are indicators of intercellular passage of the intestinal mucosa, were also determined. The concentrations of Ca in the serosal and mucosal media were 1.25 mmol/L and 10 mmol/L, respectively. After a 30-min incubation, the net Ca transport, LY passage and TEER were determined. In the control experiment, LY permeability was lowest, and TEER value was highest in the colon. The addition of 1-100 mmol/L melibiose, difructose anhydride (DFA)III, or DFAIV to the mucosal medium increased the net Ca absorption and LY permeability dose-dependently in the jejunum, ileum, cecum and colon preparations. Melibiose decreased TEER dose-dependently in the jejunum and cecum, but not in the ileum and colon. DFAIII decreased TEER dose-dependently in the jejunum, cecum and colon, but not in the ileum. DFAIV decreased TEER dose-dependently in all four intestinal portions. Positive linear relationships were found between net Ca transport and LY passage in all portions of the intestine, whereas negative linear relationships were found between net Ca absorption and TEER. We concluded that the three indigestible saccharides directly affect the epithelial tissue and activate the passage of tight junctions, thereby promoting Ca absorption in the small and large intestine in vitro. KEY WORDS: Ca absorption * indigestible saccharide * Ussing chamber * intestine * tight junction