Effect of aluminum on neurological recovery in rats following spinal cord injury.

OBJECT: This investigation was undertaken to study the effect of aluminum on neurobehavioral, electrophysiological, structural, and biochemical changes in rats following spinal cord injury (SCI). METHODS: Adult male Sprague-Dawley rats classified into different groups were given aluminum sulfate-dosed drinking water in the concentrations of 0%, 0.25%, 0.5% and 1%, respectively. After 30 days of aluminum treatment, the animals were subjected to spinal cord trauma. Laminectomy was performed at T7-8 in anesthetized rats, followed by placement of a compression plate (2.2 x 5 mm) loaded with a 35-g weight over the exposed spinal cord for 5 minutes. Control animals underwent the same surgical procedure, but the compression injury was not induced (sham). Postoperative neurological function was assessed using the inclined-plane test and by obtaining a modified Tarlov score and vocal/sensory score daily for 10 days. Electrophysiological changes were assessed using corticomotor evoked potentials, whereas pathological changes were assessed by light microscopy. The level of vitamin E in the spinal cord was measured as an index of antioxidant defense. The behavioral, biochemical, and histological analyses were performed in a blinded fashion. CONCLUSIONS: Analysis of results obtained in the behavioral studies revealed that the compression of spinal cord produced transient paraparesis in which a maximum motor deficit occurred at Day 1 following SCI and resolved over a period of 10 days. Administration of aluminum significantly impaired the recovery following SCI. Analysis of the results of the biochemical, electrophysiological, and histopathological studies also confirmed the deleterious effects of aluminum on recovery from SCI in rats.