Nanoparticle Uptake by the Rat Gastrointestinal Mucosa: Quantitation and Particle Size Dependency

TLDR

Histological studies confirmed that polystyrene microspheres are absorbed across the gastrointestinal tract and transported via mesenteric lymph to liver and spleen, as shown by gel permeation chromatography. Rats were gavaged daily with 50 nm–3 µm polystyrene microspheres (1.25 mg kg⁻¹) for 10 days, and tissue radioactivity from 100 nm and 1 µm I125‑labelled particles was measured over 8 days to assess absorption, though labeling lability limited certainty. Under these conditions, 50 nm particles were absorbed 34 % (26 % for 100 nm), with 7 % and 4 % respectively reaching liver, spleen, blood, and bone marrow; particles >100 nm failed to reach bone marrow, >300 nm were absent from blood, and no particles were detected in heart or lung.

Abstract

Abstract Polystyrene microspheres in the size range 50 nm to 3 μm were fed by gavage to female Sprague Dawley rats daily for 10 days at a dose of 1.25 mg kg−1. Previous histological evidence of the uptake of these particles and their absorption across the gastrointestinal tract and passage via the mesentery lymph supply and lymph nodes to the liver and spleen was confirmed by analysis of tissues for the presence of polystyrene by gel permeation chromatography. Measurement of radioactivity of tissues following administration of 100 nm and 1 μm I125-labelled polystyrene latex particles for 8 days was corroborative although less secure because of the potential lability of the labelled particles. The extent of absorption of 50 nm particles under the conditions of these experiments was 34% and of the 100 nm particles 26% (as measured by determination of polystyrene content), of which total, about 7% (50 nm) and 4% (100 nm), was in the liver, spleen, blood and bone marrow. Particles larger than 100 nm did not reach the bone marrow, and those larger than 300 nm were absent from blood. No particles were detected in heart or lung tissue.