Spinal cord contusion in the rat: morphometric analyses of alterations in the spinal cord.

Morphometric analyses were carried out on rat spinal cords which were injured by a weight drop technique. A 10-g weight was dropped 0.0, 2.5, 5.0, 7.5, 10.0, or 17.5 cm onto the dura which was exposed at the T8 vertebral level. Four weeks after injury, lesion volume, lesion length, and the dimensions of the tissue at the epicenter (lesion area, area of gray matter, and area of white matter) were measured and correlated with the height from which the weight was dropped and the results from tests of motor and sensory functional deficit. The results, based on linear regression analyses, indicated significant correlations between certain morphologic parameters (lesion volume, lesion length, and the area of gray and white matter at the epicenter) and both the height from which the weight was dropped and behavioral scores. Because the area of white matter at the epicenter is a very simple measurement which correlates well (r = 0.91) with behavioral outcome, this morphologic feature is a useful quantitative measure of the histopathologic consequences of spinal cord injury.