Effect of a single huge dose of methylprednisolone on blood flow, evoked potentials, and histology after acute spinal cord injury in the rat.

Effects of a single, huge dose of methylprednisolone on post-traumatic spinal cord blood flow (SCBF), evoked potentials and histological changes were studied in a rat model of spinal cord injury. The purpose of this study was to assess the optimal dose of methylprednisolone for the treatment of rat spinal cord injury. Twenty-five male Wistar rats were subjected to an acute clip compression injury at 51 g for 1 min at C8-T1, and then received an intravenous bolus injection of one of the following 30 min after injury: vehicle, 30, 60, 120 or 240 mg kg-1 methylprednisolone. SCBF was measured at the injury site and an adjacent area with the hydrogen clearance technique. Sensory evoked potentials following sciatic stimulation were recorded from the somatosensory and cerebellar cortices. Descending volleys were recorded from T9-10 spinal cord following cerebellar stimulation. SCBF and evoked potential recordings were repeated until perfusion-fixation at 4 h after injury. After injury, SCBF at both levels significantly dropped, and all evoked potentials disappeared in all animals. None of the doses of methylprednisolone improved post-traumatic SCBF, or evoked potentials. Quantitative histological assessment of the injured cords revealed no significant differences in hemorrhages or cavitation in the spinal cord among the treatment groups. This study showed that a single huge dose of methylprednisolone from 30 to 240 mg kg-1 had no beneficial effects on the traumatized rat spinal cord in the acute stage.