Glycosaminoglycan (GAG) accumulation in visceral organs of MPS VI rats. (A) Toluidine blue staining of semi-thin sections (1 μm thick) shows vacuoles filled with storage (arrows) in lysosomes of cells from liver, spleen, and kidney of 6-month-old MPS VI affected (AF) rats, which were absent in the same tissues of normal (NR) rats. Magnification: 100×. (B) Quantitative measurement of GAG accumulation via dimethyl-methylene blue method on tissue lysates from liver, spleen, and kidney of AF and NR rats. (GAG levels are expressed as μg per mg of proteins: μg GAG/mg prot). *P ≤ 0.01.