Lysosome lipid storage disorder in NCTR-BALB/c mice. II. Morphologic and cytochemical studies.

Electron-microscopic and cytochemical studies were carried out on tissues of NCTR-BALB/c mice. These mice are affected with a neurovisceral genetic disorder involving excessive tissue accumulation of lipid. Distinctive polymorphic intracellular inclusions, bounded by a membrane and containing lamellated bodies, were found in many cells of liver, spleen, lung, kidney, intestine, lymph nodes, and brain. The inclusions transformed reticuloendothelial cells into massive foam cells. Acid phosphatase cytochemical studies performed on sections of liver demonstrated that the inclusions were lysosomes. Fixation of liver in the presence of digitonin produced "spicules" in the inclusions characteristic of digitonin-cholesterol complexes. Clefts of cholesterol crystals were seen in the inclusions in liver, spleen, and lung. We conclude that the NCTR-BALB/c mice are affected by a lysosome lipid storage disease and that cholesterol is a major storage product.