EFFECT OF ANIMAL AGE ON THE UPTAKE OF LARGE PARTICULATES ACROSS THE EPITHELIUM OF THE RAT SMALL-INTESTINE

A quantitative investigation into the transfer of latex polystyrene. p articles across the epithelium of the small intestine has been carried out using male weanling, adult and aged Sprague-Dawley rats. Orally a dministered polystyrene particles, 2 mu m in diamter, were transferred from the lumen of the small intestine into the gut associated lymphoi d tissues (Peyer's patches). No significant difference in the number o f particles transported across the gut epithelium was detected between animals of different age groups. The concentration of particles detec ted in Peyer's patches excised from the proximal and distal regions of the small intestine of particle-treated animals did not differ signif icantly, except in aged rats. Particle concentration was significantly higher in Peyer's patch tissue than in adjacent Peyer's patch-free ti ssues of the small intestine in treated animals of all age groups. The assay method described here may be used for quantitative investigatio n of the transepithetial transport of large particulates.