Tissue GAG levels. Normal (grey bars), MPS I untreated mice (black solid bars) and MPS I mice treated with rhodamine B (black hatched bars) were analysed post-mortem at 6 months to determine GAG levels. Aliquots of triton extracted tissues were cpc/citrate precipitated and uronic acid was determined. Uronic acid is expressed as µg total uronic acid for brain (A), spleen (B), liver (C), heart (D), kidney (E) and lung (F). Data is expressed as average + SEM for each group. ** indicates significantly different from normal (p < 0.001, one-way ANOVA, Tukey’s post-hoc test). # indicates MPS I treated significantly different from MPS I untreated (p < 0.001, one-way ANOVA, Tukey’s post-hoc test).