Onset and regression of neuroaxonal lesions in sheep with mannosidosis induced experimentally with swainsonine.

A group of young sheep were fed a diet containing the alpha-mannosidase inhibitor swainsonine, which resulted in the induction of a neuronal lysosomal mannoside storage disease. Sheep were killed at various intervals during and following the treatment period and the nature and distribution of neuronal and axonal lesions in the brain were assessed by routine light and electron microscopy and by the rapid Golgi impregnation technique. Neuronal mannoside storage, axonal dystrophy and meganeurite formation were induced by 80 days of treatment and the lesions had regressed by 40 days after the end of treatment. The results are discussed in relation to their relevance to the current widespread interest in the pathobiology of neuronal lysosomal storage.