SPERMINE AFFECTS INTESTINAL IN-VITRO PERMEABILITY TO DIFFERENT-SIZED MOLECULES IN RATS

The gut epithelial lining is normally an effective barrier to entry of luminal bacteria and macromolecules into the body and dietary polyami nes may influence its function. Therefore, the effects of spermine on regional intestinal permeability to different-sized marker molecules i n rats were investigated in Ussing diffusion chambers. Mucosal exposur e to 1 mM spermine reduced the permeation of the marker Na-fluorescein in jejunum, expressed as the apparent permeability coefficient (P-app ). In contrast, P-app for Na-fluorescein was increased by 10 mM spermi ne in ileum and by 50 mM spermine in both jejunum and ileum. No effect s were observed on [Cr-51]-EDTA permeability in any of the intestinal regions. For the larger marker molecules, bovine serum albumin (BSA) a nd FITC-dextran 71 200 (FITC-D), mucosal exposure to 0.5 mM spermine r educed P-app in colon. Spermine (10 mM), increased P-app for FITC-D in all regions and for BSA only in ileum, while P-app for BSA was increa sed by 50 mM spermine in both jejunum and ileum. The effects of spermi ne on the intestinal permeability to different-sized molecules general ly seemed to depend on the intestinal region and on the polyamine conc entration; higher spermine concentrations (10-50 mM) enhanced, while l ower (0.5-1 mM) decreased the permeability. These findings may be impo rtant when trying to modulate epithelial barrier functions, especially during barrier dysfunction. (C) 1998 Elsevier Science Inc. All rights reserved.