Antioxidant therapy in experimental spinal cord injury

Abstract

We have tested the capacity of several compounds with in vitro and/or in vivo antioxidant or antilipolytic activity to ameliorate locomotor function in cats subjected to static loading (i.e. compression) injury of the spinal cord. These include the synthetic glucocorticoid, methylprednisolone sodium succinate (MP), and the new 21-aminosteroid antioxidant, U74006F. Treatment of spinal cord-injured cats with high doses of MP promoted or spared locomotor function and preserved spinal cord tissue. Extending these findings in cats to humans, it was recently demonstrated that high doses of MP administered within 8 h of injury significantly improved neurologic recovery in human spinal cord-injured patients. The compound U74006F is one of a series of 21-aminosteroids that, unlike MP, lack glucocorticoid, mineralocorticoid or other hormonal activity yet are potent inhibitors of lipid perioxidation. Over a 100-fold range of doses, U74006F promoted recovery of locomotor function in spinal cord-injured cats. The lowest effective dose for U74006F was 100 times lower than the maximally effective dose for MP. The efficacy of U74006F is unchanged if treatment is initiated within 4 h of injury. However, if treatment is delayed for 8 h, the therapeutic potency of U74006F is substantially reduced. These findings suggest that antioxidant therapy can successfully limit the effects of both experimental and clinical spinal cord injury especially if the treatment is initiated shortly after injury.