EFFECT OF SOLID AND LIQUID DIET ON UPTAKE OF LARGE PARTICULATES ACROSS INTESTINAL EPITHELIUM IN RATS

The effect of diet composition on the uptake of particulates across th e gastrointestinal epithelium has been examined in fasted male weanlin g Sprague-Dawley rats by estimating the systemic uptake of orally admi nistered 2-mu m latex polystyrene microspheres. Using a tissue solubil ization assay, particle transfer in animals maintained on a fluid diet was determined. A larger number of particles was transferred from the gut lumen to the internal organs, including the mesenteric lymph node , spleen, bone marrow, liver, kidney, and heart of animals fed solid p elleted diet than those maintained on a fluid-diet 4 hr after oral adm inistration of particles. The increase in particle number in rats fed the solid diet was only statistically significant (P < 0.05) for brain tissue in the analysis for trend. However, the number of particles re tained in the proximal region of the gut at the end of this period was greater in animals fed the fluid diet. This work demonstrates that di et composition is important in gastrointestinal transepithelial transl ocation of microspheres.