MICROTUBULE-ASSOCIATED PROTEIN-2 AS A SENSITIVE MARKER FOR DENDRITE LESIONS AFTER SPINAL-CORD TRAUMA - AN IMMUNOHISTOCHEMICAL STUDY IN THE RAT

We evaluated, by immunohistochemistry, the changes of microtubule-asso ciated protein 2 (MAP2) of rat spinal cord following compression injur y of mild, moderate and severe degrees at the Th-8-9 level. The spinal cord of normal rats and animals subjected to laminectomy only, presen ted immunoreactivity to MAP2 in nerve cell bodies and dendrites but no t in axons and other structures. Following moderate and severe compres sion resulting in reversible paraparesis or irreversible paraplegia, r espectively, the compressed segment showed loss of MAP2 immunoreactivi ty in dendrites and nerve cell bodies already 4 h after injury. This p henomenon remained throughout the experimental period of 9 days. Our f indings indicate that there is a rapid and long-lasting reduction of M AP2 in nerve cell bodies and dendrites of the compressed segment and t hat this alteration is related to the degree of the impact to the cord . The reduction of MAP2 may well have functional implications by inter fering with neurotransmission. MAP2 immunostaining is an excellent way of studying dendritic changes in spinal cord trauma and can be used i n future experiments designed to investigate the influence of various therapeutic measures on secondary lesions after trauma.