Transient early expression of TNF-α in sciatic nerve and dorsal root ganglia in a mouse model of painful peripheral neuropathy

Paola Sacerdote, Silvia Franchi, Anna Elisa Trovato, Anna Elisa Valsecchi, Alberto E. Panerai, Mariapia Colleoni

Research output: Contribution to journalArticle

Abstract

The proinflammatory cytokine tumor necrosis factor-α (TNF) is an important mediator in neuropathic pain. We investigated the temporal pattern of TNF mRNA expression in the sciatic nerve, in dorsal root ganglia (DRG) and spinal cord in the mouse chronic constriction injury model of neuropathy with quantitative real-time polymerase chain reaction. Neuropathic pain-like behaviour was monitored by evaluating thermal hyperalgesia and mechanical allodynia. Pain-related behaviour and TNF expression were evaluated 6 h, 1, 3, 7 and 14 days after injury. Naive animals and sham-operated mice were used as controls. We found an early upregulation of sciatic nerve TNF mRNA levels in chronic constriction injury (CCI) and sham-operated animals 6 h after surgery: 1 day later TNF overexpression was present in CCI mice only and disappeared 3 days after injury. The mRNA cytokine levels were elevated in DRG 1 and 3 days after surgery in CCI animals only, while the cytokine was not modulated in the spinal cord. A significant hyperalgesia was present in CCI and sham-operated mice at 6 h and 1 day, while at later time point only CCI mice presented lower thresholds. Mechanical allodynia was already present only in CCI animals 6 h from surgery and remained constant up to the 14th day. The results indicate that a transient early TNF upregulation takes place in peripheral nervous system after CCI that can activate a cascade of proinflammatory/pronociceptive mediators.

Original languageEnglish
Pages (from-to)210-213
Number of pages4
JournalNeuroscience Letters
Volume436
Issue number2
DOIs
Publication statusPublished - May 9 2008

Keywords

  • Allodynia
  • Chronic constriction injury
  • Hyperalgesia
  • Neuropathy
  • TNF-α

ASJC Scopus subject areas

  • Neuroscience(all)

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