Tumor necrosis factor receptor 1 and 2 proteins are differentially regulated during Wallerian degeneration of mouse sciatic nerve.

The pro-inflammatory cytokine tumor necrosis factor-alpha (TNF) is involved in injury-induced peripheral nerve pathology and in the generation of neuropathic pain. Here, we investigated local protein levels of the two known TNF receptors, TNF receptor 1 and 2 (TNFR1, TNFR2), on days 0, 1, 3, 7, 14, and 28 after unilateral crush or chronic constriction injury (CCI) of mouse sciatic nerves using enzyme-linked immunoassay. Both receptors were detectable at a low level in nerve homogenates from naive mice. After crush or CCI, TNFR1 increased by 2-fold on days 3 and day 7. Unlike TNFR1, TNFR2 was markedly upregulated already on day 1 after crush or CCI. TNFR2 increased by 7-fold on days 3 and 7, and remained elevated at a lower level until day 28 after both CCI and crush injury. These data indicate that endoneurial TNFR1 and TNFR2 proteins are differentially regulated during Wallerian degeneration.