Early cytokine gene expression in mouse CNS after peripheral nerve lesion.

The generation and maintenance of pain after peripheral nerve injury are thought to be influenced by cytokine signaling. Chronic constriction injury (CCI) to mouse sciatic nerve leads to an early local upregulation of pro-inflammatory cytokines already 1 h after the lesion. The early regulation of cytokines in pain related CNS areas is largely unknown.

Early cytokine expression in mouse sciatic nerve after chronic constriction nerve injury depends on calpain.

Nerve injury initiates Wallerian degeneration with subsequent alterations of cytokine expression contributing to neuropathic pain. To investigate the very early temporal pattern of cytokine regulation we studied 140 mice of C57Bl/6J background after chronic constriction injury (CCI) of the right sciatic nerve and measured the relative mRNA expression of the pro-inflammatory cytokines tumor necrosis factor-alpha (TNF) and interleukin-1beta (IL-1beta) and of the anti-inflammatory cytokines IL-4 and IL-10 with quantitative real-time polymerase chain reaction (qRT-PCR). The measurements were performed in ipsi- and contralateral sciatic nerves and dorsal root ganglia (DRG) 1, 3, 6, 9, 12, 24 h, and 3 and 7 days after CCI.