Neuromotor alterations and cerebellar deficits in aged arylsulfatase A-deficient transgenic mice

Arylsulfatase A (ASA)-deficient (-/-) mice and ASA(+/+) controls were constructed as a transgenic model for the lysosomal storage disease, metachromatic leukodystrophy (MLD). One-year-old ASA(-/-) mice showed impaired rotarod performance and altered walking pattern characterized by a shorter pace, later evolving into more severe ataxia with tremor in 2-year-old mice. Examination of cerebellar histology showed that 2-year-old ASA(-/-) mice have lost most of the calbindin immunoreactivity from their Purkinje cell dendrites and show simplified dendritic architecture. Additionally, ASA-deficient mice lost a substantial proportion of their Purkinje cells. Recordings of unitary potentials and stimulation of climbing fibers on cerebellar slices from 2-year-old mice indicated that, although the main cerebellar synapses seem to be present and functioning physiologically, the climbing fibers of ASA-deficient mice may have enhanced effects on Purkinje cell activity. It is concluded that ambulatory dysfunctions in ASA(-/-) mice might be explained by an imbalance in the consequences of climbing fiber signals upon Purkinje cell activity due to selective neurodegeneration within the cerebellum. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.