Morphogenesis of Light and Electron Microscopic Lesions in Porcine GM2-Gangliosidosis

Abstract

The neurons and glial cells of 1- to 140-day-old pigs with GM2-gangliosidosis had membranous cytoplasmic inclusion bodies. These bodies appeared as small vacuolated cytoplasmic structures in paraffin-embedded, hematoxylin and eosin-stained sections and as solid, dark, round granules in 1-micrometer sections embedded in plastic and stained with toluidine blue. Ultrastructurally, the cytoplasmic inclusion bodies appeared as round, dense structures from 0.6 to 1.2 micrometers in diameter, that were filled with various amounts of small to large arrays of membranous lamellae. The cortical neuronal inclusions were seen initially as lysosomes containing a small amount of particulate material. The appearance of these inclusions changed as they progressed through different configurational stages. Inclusions resembled the granulomembranous body, the zebra body, possibly other intermediate forms and, finally, the classical membranous cytoplasmic body. The cytoplasmic inclusions in glial cells resembled membranovesicular bodies and, although also of apparent lysosomal origin, were morphologically different from the neuronal inclusions. The morphologic lesions in the neurons and glial cells of the affected pigs were similar to those described for human gangliosidoses.