Encapsulation in heparin/chitosan particles greatly enhances the ability of recombinant TNF to effect popliteal LN enlargement 24 h after footpad injection. (A) DIC micrograph showing purified rat MC-derived particles. (B) Micrograph showing synthetic heparin/chitosan microparticles. These micrographs are representative of more than three independent experiments. Bars, 10 µm. (C) Less than 1 ng rTNF encapsulated in ∼1.3 × 105 synthetic particles similar to MC granule particles elicits more LN enlargement than 10 ng of soluble TNF when injected into the footpads of mice. Black bars, particles with and without encapsulated TNF; open bars, soluble TNF; hatched bar, soluble TNF mixed with soluble chitosan and heparin (n = 3 for each group; *, P < 0.05 vs. 10 ng soluble TNF; **, P < 0.01 vs. particles without TNF, 1 ng soluble TNF, and 1 ng soluble TNF mixed with soluble chitosan and heparin; data analyzed by one-way analysis of variance followed by Tukey’s Multiple Comparisons test; error bars indicate standard error of the mean). Results shown are representative of two independent experiments.
