EFFECTS OF TRH AND HIGH-DOSE CORTICOSTEROID-THERAPY ON EVOKED-POTENTIALS, AND TISSUE NA-CONTENT IN EXPERIMENTAL SPINAL-INJURY(, K+ AND WATER)

The therapeutic effects of continuous infusion of thyrotropin-releasin g hormone (TRH) and methylprednisolone (MP) in experimental spinal cor d injury were studied in Swiss albino rats. Thirty rats received a 53- g clip-compression injury on the cord at T1, then were allocated rando mly and blindly to one of three treatment groups (ten animals in each) : (1) control; received equal volumes of saline solution; (2) MP; rece ived 30 mg/kg methylprednisolone i.v. 1 h after trauma, followed by in fusion of 5.4 mg/kg/per hour i.v. for 3 h. (3) TRH: received 2 mg/kg T RH i.v. 1 h after trauma, followed by infusion of 1 mg/kg/per hour i.v . for 3h. MP and TRH treatments significantly improved somatosensory-e voked potentials (SEPs; P < 0.001). Both treatments significantly redu ced water content, decreased Na+ content and increased the K+ content of the cord segment that included the centre of the impact (P < 0.01). Our data provide evidence for the beneficial effects of high-dose cor ticosteroid and TRH in promoting electrophysiological recovery and pre serving spinal cord tissue following experimental injury.