Morphological Changes in Anterior Horn Cells, Immunoreactivity to Neurotrophic Factors, and Neuronal Cell Death of Spinal Cord Lesions in the Spinal Hyperostotic Mouse (twy/twy) with Chronic Mechanical Cord Compression

We examined the morphology of spinal accessory motoneurons, immunoreactivity to brain-derived neurotrophic factor (BDNF) and neurotrophin (NT)-3, and reactive astrocytosis in 70 tiptoe-walking Yoshimura (twy/twy) mice that develop calcification at C1–C2 vertebral level compressing the spinal cord. At the level of compression, the area of neuronal soma, total length of dendrites, and numbers of wheat germ agglutinin-horseradish peroxidase (WGA-HRP)-labeled accessory motoneurons decreased significantly. Rostral to the compressive lesion, opposite findings were evidenced; enhanced BDNF and NT-3 immunoreactivities were evident in the anterior horn cells, increasing in response to a more severe degree of compression, with larger population of BDNF-positive astrocyte-like cells.