EFFECTS OF LECITHINIZED SUPEROXIDE-DISMUTASE ON RAT SPINAL-CORD INJURY

Although superoxide dismutase (SOD) has been reported to promote funct ional recovery in ischemic spinal cord injury, it presents many diffic ulties in practical use primarily due to its short half-life in vivo a nd low tissue affinity. In this study, we investigated the effects of a new type of SOD, a lecithinized superoxide dismutase (PC-SOD), on mo tor disturbances, spinal cord edema, levels of myeloperoxidase (MPO), and spinal cord blood flow (SCBF) after spinal cord injury (SCI) in ra ts, PC-SOD is reported to show a delayed plasma disappearance in vivo in rats and has a higher affinity for vascular endothelium cells, neut rophils, and other cells than unmodified SOD. PC-SOD (4000 units/kg), unmodified SOD (4000 units/kg), or vehicle was injected intravenously 30 min after SCI. Four hours after SCI, SOD activities in spinal cord tissue and plasma were significantly higher in the PC-SOD group than i n the unmodified SOD group. In the PC-SOD-treated rats, motor function was significantly better than in the other 2 groups of rats. PC-SOD s ignificantly suppressed MPO activity, an indicator of neutrophils infi ltration, in the spinal cord, at 4, 8, and 24 h after SCI, and spinal cord edema at 24 h after SCI. Moreover, the decrease of SCBF after SCI was less marked in the PC-SOD group. The present results suggest that lecithinization can improve the drug delivery of SOD to the spinal co rd and PC-SOD may be an alternative pharmacological treatment for SCI.