Anti-TNF-alpha antibody reduces pain-behavioral changes induced by epidural application of nucleus pulposus in a rat model depending on the timing of administration.

Study Design: An experimental animal study.
Objective: To study if antitumor necrosis factor-alpha (TNF-alpha) antibody, which is administered at different times, reduces the pain behavior induced by application of nucleus pulposus (NP) to the nerve root.
Summary of Background Data: Treatment with TNF-alpha inhibitor reduces the pain-related behavior induced by epidural application of NP in rats.
Methods: Left L5 partial laminectomy was performed and NP was applied to the L5 nerve root in 24 rats. The rats were divided into 4 groups. In 3 groups, anti-rat TNF-alpha antibody was intravenously administered immediately after, or 6 or 20 days after NP application. The fourth group was not treated with anti-rat TNF-alpha antibody (untreated rats). The withdrawal threshold of the plantar surface was determined 1 day before up through 28 days after NP application.
Results: The withdrawal threshold of rats that had been treated with anti-rat TNF-alpha antibody immediately after or 6 days after, but not 20 days after, NP application, was significantly higher than that of the untreated rats.
Conclusions: Anti-TNF-alpha antibody reduced allodynia only when it was administered soon after the onset of allodynia. Late administration of anti-TNF-alpha antibody did not have an antiallodynic effect.