Quantitative changes of IL-6 protein are present not only in the lumbal, but also in the cervical DRG following unilateral sciatic nerve injury
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Year of publication | 2007 |
Type | Appeared in Conference without Proceedings |
MU Faculty or unit | |
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Description | Several lines of evidence suggest that pro- and anti-inflammatory cytokines contribute to both the induction and maintenance of neuropathic pain derived from cellular and molecular changes in the DRG including the activity of the primary sensory neurons. Interleukin-6 (IL-6) is a pleiotropic cytokine of the family containing IL-11, ciliary neurotrophic factor (CNTF), cardiotrophin-1 (CT-1), cardiotrophin-like cytokine (CLC), leukemia inhibitory factor (LIF), oncostatin M. A significant involvement of IL-6 in neuropathic pain induction and modulation of nerve regeneration is suggested from several experiments. Chronic constriction injury (CCI) of sciatic nerve is well-characterized experimental model of neuropathic pain. We used this model to study quantitative changes of IL-6 protein in the rat cervical and lumbal DRG. ELISA was employed to quantify IL6 protein in both ipsi- and contralateral cervical (C-DRG) as well as lumbal (L-DRG) dorsal root ganglia from naive rats and those operated for unilateral CCI of sciatic nerve with periods of survival for 1, 3, 7, and 14 days. One day after CCI, an increase of IL-6 protein was measured in the ipsilateral cervical dorsal root ganglia (C-DRGi) with a peak on day 3. On day 14 from operation a level of IL-6 protein was close to the control baseline level. Contralateral cervical ganglia (C-DRGc) displayed only a mild decrease of IL-6 protein on day 7. No significant changes were found in other periods of survival, and the IL-6 protein level reached to control baseline levels on day 14. In comparison with the naive DRG, the IL-6 protein of ipsilateral lumbal ganglia (L-DRGi) elevated from postoperation day 1, and the higher level of IL-6 remained up to 14 days from operation. The IL-6 protein level in the contralateral lumbal ganglia (L-DRGc) peaked on day 3, and enhanced level was measured till 14 days. These data provide evidence for changes of IL-6 protein levels not only in the DRG associated with damaged nerve, but also in the DRG non-associated with nerve injury in the rat experimental neuropathic pain model. |
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