Lysosomal Storage in MPS I Mice
(A) Glycosaminoglycan levels in internal organs of antibody-positive and antibody-negative MPS I mice (n = 5 per group) after 16 weeks of rhIDU treatment compared to controls. Ten untreated MPS I mice (MPS I NoTx) and ten untreated wild-type normal mice (Normal NoTx) were used as controls (n = 10 per group). Glycosaminoglycans were measured by the carbazole reaction and reported as mol glucuronic acid (GA) per mg protein. Error bars represent SD. *p < 0.05 versus MPS I NoTx. (B and C) Lysosomal-associated membrane protein staining in liver of MPS I and normal mice. Representative images are shown of untreated wild-type mice (Normal NoTx; n = 3), untreated MPS I mice (MPS I NoTx; n = 3), MPS I mice treated with rhIDU with anti-IDU antibody titers 3–30 OD U/μL (AB Positive; n = 4), and MPS I mice treated with rhIDU with anti-IDU antibody titers < 1 OD U/μL (AB Negative; n = 4). 20× magnification (B); scale bar, 100 μm (B). 40× magnification (C); scale bar, 50 µm.