Microtubule-associated protein 2 as a sensitive marker for dendrite lesions after spinal cord trauma: an immunohistochemical study in the rat.

We evaluated, by irnmunohistochemistry, the changes of microtubule-associated protein 2 (MAP2) of rat spinal cord following compression injury of mild, moderate and severe degrees at the Th8-9 level. The spinal cord of normal rats and animals subjected to laminectomy only, presented immunoreactivity to MAP2 in nerve cell bodies and dendrites but not in axons and other structures. Following moderate and severe compression resulting in reversible paraparesis or irreversible paraplegia, respectively, the compressed segment showed loss of MAP2 immunoreactivity in dendrites and nerve cell bodies already 4 h after injury. This phenomenon remained throughout the experimental period of 9 days. Our findings indicate that there is a rapid and long-lasting reduction of MAP2 in nerve cell bodies and dendrites of the compressed segment and that this alteration is related to the degree of the impact to the cord. The reduction of MAP2 may well have functional implications by interfering with neurotransmission. MAP2 immuno-staining is an excellent way of studying dendritic changes in spinal cord trauma and can be used in future experiments designed to investigate the influence of various therapeutic measures on secondary lesions after trauma.