CHANGES, WITH AGE, IN THE PHOSPHOLIPID CONTENT OF THE INTESTINAL MUCUS LAYER OF THE NEWBORN RABBIT

Background/Purpose: The high incidence of bacterial translocation in n ewborns is thought to be caused, in part, by the immaturity of the int estinal mucosal barrier. Recently, intestinal mucus phospholipids (PL) have been reported to be important factors in the function of this mu cosal barrier. The aim of this study was to quantify changes, with age , in the intestinal mucus PL of the newborn rabbit. Methods: Mucus was gently scraped from the small intestinal mucosal surface of rabbits o f different ages (0, 7, 14, and 28 days old and adult; n = 6 for all g roups). PL was extracted from the mucus and was separated by two-dimen sional thin-layer chromatography. The isolated phospholipid spots were quantified for their phosphorus content. Results: Total PL content of the mucus decreased significantly with age (day 0, 21 +/- 2; day 7, 1 6 +/- 4; day 14, 9 +/- 3; day 28, 2 +/- 1; adult, 1 +/- 1 mu mol/g wet mucus; P=.0001). Phosphatidylcholine and phosphatidylethanolamine lev els in the adult rabbits were significantly lower in comparison with t he 0-, 7-, and 14-day-old pups (P <.05). In contrast, lysophosphatidyl choline and lysophosphatidylethanolamine were significantly higher in the 28-day-old and adult rabbits in comparison with the 0-, 7-, and 14 -day-old pups (P<.05). Phosphatidylinositol + phosphatidylserine level s in 7-day-old rabbits was significantly higher compared with adult ra bbits. There was no significant difference in the composition of sphin gomyeline between groups. Conclusion: Significant changes in the conte nt and composition of the intestinal mucus phospholipids were observed during the first month of life in rabbits. Copyright (C) 1998 by W.B. Saunders Company.