Neurophysiologic Changes in Lumbar Nerve Root Inflammation in the Rat after Treatment with Cytokine Inhibitors: Evidence for a Role of Interleukin-1

Study Design. The present study was designed to evaluate the effect of cytokine inhibitors in experimental allergic radiculitis. Objective. Evaluation of the effect of cytokine inhibitors in experimental allergic radiculitis. Summary of Background Data. A number of cytokines are known to be involved in hyperalgesia and may play a role in radiculitis. Corticosteroids and other cytokine inhibitors antagonize their effects. Methods. Experimental allergic radiculitis was induced in rats by injection of bovine myelin from the peripheral nervous system. The sham group subsequently received saline injections; the treatment groups received either prednisolone or interleukin-1 receptor antagonist. Treatment effect was assessed on the basis of motor performance and neurophysiologic parameters. Results. Treatment ameliorated the symptoms of experimental allergic radiculitis. Prednisolone appeared to be somewhat more effective than interleukin-1 receptor antagonist. Conclusions. Because interleukin-1 receptor antagonist specifically blocks the effects of interleukin-1 at its receptors, the present results imply that interleukin-1 is a causal factor in the model of experimental radiculitis used. Its specificity and apparent lack of side effects make interleukin-1 receptor antagonist an attractive candidate treatment for the human disease.