Publication details
Dynamics of interleukin-6 elevation in rat lumbar ganglia of rheumatoid arthritis model
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| Year of publication | 2014 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Rheumatoid arthritis (RA) is autoimmune inflammatory disease that affected many tissues and organs. RA is associated with an increased production of a range of cytokines. Interleukin 6 (IL-6) is an injury-induced factor that contributes significantly to maintenance of neuropathic pain. The aim of present study was to determine the temporal changes of IL-6 protein in L3 and L5 dorsal root ganglia (DRG) related with afferent innervation of the knee joint in AIA model. In addition, we monitored manifestation of neuropathic pain using behavioral test. For induction of unilateral antigen-induced arthritis (AIA), rats (n=33) were immunized by an intra-articular injection of Complete Freund’s Adjuvant (CFA, 50 µl) into the right knee joint. The knee joints of naive and control rats (n=15) injected with 50 µl of sterile saline were used for comparison with AIA induction. All experimental animals were left to survive for 1, 2, 4, 14 and 21 days. Upregulation of IL-6 protein in DRG was analyzed by immunofluorescence staining and quantified by Western blot analysis. Neuropathic pain expressed by mechanical hyperalgesia was measured using the dynamic plantar esthesiometer. For thermal hyperalgesia, withdrawal time was measured and the intensity radiance was set to a value of 50. The data differences were evaluated by Mann-Whitney test using STATISTICA software. Increasing of IL-6 protein was found in both L3 DRG and L5 DRG compared with DRG from naive rats. Elevation of IL-6 protein level was observed in both ipsilateral and contralateral L3 DRG in the overall time period except in contralateral L3 DRG at the first day. L5 DRG also showed bilateral but delayed increase in IL-6 protein compare to L3 DRG. Statistically insignificant IL-6 elevation was in ipsilateral L5 DRG during the first two days and in contralateral L5 DRG in the first day. Mechanical allodynia was measured in the ipsilateral hind paws from 1 day to 14 days, in the contralateral hind paws in the period from 7 to 14 days after RA induction. By contrast, hypersensitivity for thermal stimuli was monitored bilaterally during the first fourth days and then 21 day, in the period between the 4 and 14 days has occurred normalization to value before CFA application. The difference at the contralateral side against the ipsilateral hind paws is that a statistically significant decrease was observed only at 4 and 21 days, after the application CFA. Dynamic of IL-6 elevation was found bilaterally in L3 and L5 DRGs of rats subjected by unilateral AIA in correlation with hyperalgesia from 1 to 21 days. The results of increasing of IL-6 protein in L3 and L5 DRGs are related with afferent innervation of ventral and dorsal part of the knee joint. Supported by the project CEITEC (CZ.1.05/1.1.00/02.0068) from European Regional Development Fund. |
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