Ascorbic acid: a putative biochemical marker of irreversible neurologic functional loss following spinal cord injury.

The development of permanent paraplegia in spinal injured cats is accompanied by a large progressive decline in total ascorbic acid (AA) and a transient increase in oxidized (AAox) ascorbate. Since AA is involved in a variety of processes required for normal central nervous system (CNS) performance we suggested that such large ascorbate loss may contribute to derangements in spinal cord function following injury. We now demonstrate that methylprednisolone (15 mg/kg) and naloxone (10 mg/kg), two treatments that preserve neurologic function in this model, rapidly block deteriorating ascorbate status. Naloxone at 1 mg/kg, a treatment providing no therapeutic benefit, has no protective effect on ascorbate. The results strongly support the hypothesis that loss of ascorbate homeostasis reflects irreversible loss of neurologic function following spinal cord injury.