Cerebellar cell degeneration in the leaner mutant mouse

Area of Science:

• Neuroscience
• Developmental Biology
• Genetics

Background:

• The leaner mouse mutation is an autosomal recessive disorder.
• It is characterized by severe ataxia and significant cellular loss in the cerebellar cortex.

Purpose of the Study:

• To establish a developmental profile of cellular degeneration in the leaner mouse cerebellum.
• To investigate the timing and pattern of cell loss in different cerebellar cell types.

Main Methods:

• Developmental profiling of cellular losses in the cerebellar cortex of leaner mice.
• Quantitative analysis of granule, Purkinje, and Golgi cells.
• Histological examination for pycnotic cells indicating degeneration.

Main Results:

• Granule cells are the first to degenerate, with pycnotic cells observed from postnatal day 10, concentrated in anterior folia.
• Progressive loss of Golgi cells (to ~50% of wild-type) and severe loss of Purkinje cells (to ~20% of wild-type) occur.
• Cell loss, particularly of Purkinje cells, shows regional variation, being more rapid in anterior folia and continuing at a low rate throughout the animal's life.

Conclusions:

• The leaner mutation leads to a protracted and regionally variable pattern of cerebellar cell degeneration.
• Cell loss in Purkinje and Golgi cells begins late in cerebellar maturation, after the main developmental events.
• The leaner mouse serves as a model for studying the heterogeneity of disease expression in cerebellar ataxias.