Effect of thalidomide on signal transduction pathways and secondary damage in experimental spinal cord trauma

TNF-alpha seems to play a central role in the inflammatory process of spinal cord injury. We tested the neuroprotective effects of thalidomide, an immunomodulatory agent that inhibits TNF-alpha production, which have not been investigated so far. The aim of our study was to evaluate the therapeutic efficacy of thalidomide in an experimental model of spinal cord trauma, which was induced by the application of vascular clips (force of 24 g) to the dura via a 4-level T5 to T8 laminectomy. Spinal cord injury in mice resulted in severe trauma characterized by edema, neutrophil infiltration, and cytokine production that is followed by recruitment of other inflammatory cells, production of a range of inflammation mediators, tissue damage, apoptosis, and disease. Thalidomide treatment significantly reduced the degree of: 1) spinal cord inflammation and tissue injury (histological score); 2) neutrophil infiltration (myeloperoxidase evaluation); 3) iNOS, nitrotyrosine, lipid peroxidation, and cytokine expression (TNF-alpha and IL-1beta); 4) apoptosis (terminal deoxynucleotidyltransferase-mediated UTP end labeling staining, and Bax and Bcl-2 expression); and 5) nuclear factor-kappaB activation. In a separate set of experiments, we have also clearly demonstrated that thalidomide significantly ameliorated the recovery of limb function (evaluated by motor recovery score). Taken together, our results clearly demonstrate that treatment with thalidomide reduces the development of inflammation and tissue injury events associated with spinal cord trauma.