Object: The nuclear factor-kappaB (NF-kappaB) is a transcription factor that plays a pivotal role in the induction of genes involved in physiological processes and in the response to inflammation. The authors of recent studies have demonstrated that NF-kappaB and oxidative stress contribute to secondary injury after impact-induced spinal cord injury (SCI) in the rat. Dithiocarbamates are antioxidants that are potent inhibitors of NF-kappaB. The authors postulated that pyrrolidine dithiocarbamate (PDTC) would attenuate NF-kappaB-related inflammatory and oxidative events that occur after SCI.
Methods: Spinal cord injury was induced by the application of vascular clips (force of 50 g) to the dura mater after a four-level T5-8 laminectomy. The authors investigated the effects of PDTC (30 mg/kg administered 30 minutes before SCI and 6 hours after SCI) on the development of the inflammatory response associated with SCI in rats. Levels of myeloperoxidase activity were measured as an indicator of polymorphonuclear infiltration; malondialdehyde levels in the spinal cord tissue were determined as an indicator of lipid peroxidation. The following studies were performed: immunohistochemical analysis to assess levels of inducible nitric oxide synthase (iNOS), nitrotyrosine formation, poly([adenosine diphosphate]-ribose) polymerase (PARP) activity; Western blot analysis to determine cytoplasmic levels of inhibitory-kappaB-alpha (IkappaB-alpha); and electrophoretic mobility-shift assay to measure the level of DNA/NF-kappaB binding. The PDTC treatment exerted potent antiinflammatory effects with significant reduction of polymorphonuclear cell infiltration, lipid peroxidation, and iNOS activity. Furthermore, administration of PDTC reduced immunohistochemical evidence of formation of nitrotyrosine and PARP activation in the spinal cord section obtained in the SCI-treated rats. Additionally, PDTC treatment significantly prevented the activation of NF-kappaB (electrophoretic mobility-shift assay and immunoblot analysis).
Conclusions: Overall, the results clearly demonstrate that PDTC-related prevention of the activation of NF-kappaB reduces the development of some secondary injury events after SCI. Therefore, inhibition of NF-kappaB may represent a novel approach in the treatment of SCIs.