In Brief:
In a new model of herniation of nucleus pulposus (HNP), nucleus pulposus (NP) application to the dorsal root ganglion caused elevation of interleukin (IL)-6, tumor necrosis factor α (TNF-α), interferon-g (IFN-γ), and IL-4. IFN-γ-blockade prevented NP-induced elevation of IL-6, TNF-α, and IFN-γ. Elevation of IL-1β and IL-10 after surgery was not enhanced by NP. IL-6, TNF-α, and IFN-γ may interact during neural root irritation from HNP.