Spatiotemporal progression of neurodegeneration and glia activation in the wobbler neuropathy of the mouse

THE wobbler mouse (phenotype WR; genotype wr/wr) has been investigated as a model for neurodegenerative diseases like SMA and ALS. A new diagnostic marker based on a polymorphism in the closely linked chaperonine gene Cct4 enabled us to diagnose the allelic status at the wr locus within the original background strain C57BL/6. Using this marker, we investigated the spatiotemporal progression of neuropathology in WR mice from postnatal day (d.p.n.) 10 to 60. Neurodegeneration starts at 13 d.p.n. in the thalamus (N. ventralis), in deep cerebellar nuclei, brain stem (N. vestibularis) and spinal cord interneurons. The motor nuclei of spinal nerves and motoneurons degenerate from 15 d.p.n. onward. Reactive astrocytes are observed around 17 d.p.n. in the white and grey matter of the spinal cord. Microgliosis occurs only from 23 d.p.n. onward. Our data demonstrate that in the WR disease, neurodegeneration in thalamus, cerebellum, and brain stem precedes motoneuron degeneration, astrogliosis and microgliosis.