Bilateral changes of IL-6 protein levels in the rat dorsal root ganglia associated and non-associated with nerve injury
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| Year of publication | 2008 |
| Type | Appeared in Conference without Proceedings |
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| Description | Peripheral nerve injury results in neuroimmunologic responses that may be integral to the development and maintenance of the neuropathic pain. Recent data have demonstrated that cytokines may be strongly implicated in the generation of pain states at both peripheral and central nervous system sites. This study sought to evaluate both spatial and temporal changes of IL-6 protein levels in ipsi- and contralateral lumbal (L4-L5) and also within cervical (C6-C7) dorsal root ganglia (DRG) after the lesion of peripheral nerves. Commercially available ELISA test (BioSource, CA, USA) was used for quantitative analysis of IL-6 protein. Male Wistar rats weighing (250-300 g) were divided into four groups: i/ rats underwent aseptic triple unilateral ligation of sciatic nerve (ScNL; n=12); ii/ rats operated on ligature of L4-L5 spinal nerves (SNL; n=12), all operated animals were left to survive for 1, 3, 7 and 14 days; iii/ no nerve lesions were produced in animals of naive control group (n=9); iv/ sham operated group (n=12) with periods of survival 3 and 14 days. One day after ScNL, significantly increased levels of IL-6 protein were measured in both ipsilateral and contralateral cervical and lumbal DRG. The DRG from other periods of survival displayed just mild increase of IL-6 protein levels close to the control (naive group) baseline level. After SNL operation, IL-6 protein was significantly increased from post-operation day 1, and rose up to 14 days not only in ipsi- and contralateral L4-L5 DRG, but also in ipsi- and contralateral C6-C7 DRG. Within the lumbal DRG the elevation of IL-6 protein was distinct from that one observed in cervical DRG of both neuropathic pain models. The obtained data provide evidence for changes of IL-6 protein levels not only in the DRG associated with damaged nerve (L4-L5), but also in those non-associated with nerve injury (C6-C7) in two rat experimental neuropathic pain models. Stimuli for bilateral increase of IL-6 protein in the DRG after unilateral nervous lesion are probably of systemic character. |