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Holló K, Ducza L, Hegyi Z, Dócs K, Hegedűs K, Bakk E, Papp I, Kis G, Mészár Z, Bardóczi Z, Antal M. Interleukin-1 receptor type 1 is overexpressed in neurons but not in glial cells within the rat superficial spinal dorsal horn in complete Freund adjuvant-induced inflammatory pain. J Neuroinflammation 2017. [PMID: 28645297 PMCID: PMC5482961 DOI: 10.1186/s12974-017-0902-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Background All known biological functions of the pro-inflammatory cytokine interleukin-1β (IL-1β) are mediated by type 1 interleukin receptor (IL-1R1). IL-1β–IL-1R1 signaling modulates various neuronal functions including spinal pain processing. Although the role of IL-1β in pain processing is generally accepted, there is a discussion in the literature whether IL-1β exerts its effect on spinal pain processing by activating neuronal or glial IL-1R1. To contribute to this debate, here we investigated the expression and cellular distribution of IL-1R1 in the superficial spinal dorsal horn in control animals and also in inflammatory pain. Methods Experiments were performed on rats and wild type as well as IL-1R1-deficient mice. Inflammatory pain was evoked by unilateral intraplantar injection of complete Freund adjuvant (CFA). The nociceptive responsiveness of control and CFA-treated animals were tested daily for withdrawal responses to mechanical and thermal stimuli before and after CFA injection. Changes in the expression of 48 selected genes/mRNAs and in the quantity of IL-1R1 protein during the first 3 days after CFA injection were measured with the TaqMan low-density array method and Western blot analysis, respectively. The cellular localization of IL-1R1 protein was investigated with single and double staining immunocytochemical methods. Results We found a six times and two times increase in IL-1R1 mRNA and protein levels, respectively, in the dorsal horn of CFA-injected animals 3 days after CFA injection, at the time of the summit of mechanical and thermal allodynia. Studying the cellular distribution of IL-1R1, we found an abundant expression of IL-1R1 on the somatodendritic compartment of neurons and an enrichment of the receptor in the postsynaptic membranes of some excitatory synapses. In contrast to the robust neuronal localization, we observed only a moderate expression of IL-1R1 on astrocytes and a negligible one on microglial cells. CFA injection into the hind paw caused a remarkable increase in the expression of IL-1R1 in neurons, but did not alter the glial expression of the receptor. Conclusion The results suggest that IL-1β exerts its effect on spinal pain processing primarily through neuronal IL-1R1, but it can also interact in some extent with IL-1R1 expressed by astrocytes.
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Affiliation(s)
- Krisztina Holló
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - László Ducza
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Zoltán Hegyi
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Klaudia Dócs
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Krisztina Hegedűs
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Erzsébet Bakk
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Ildikó Papp
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary.,Department of Anatomy, Histology and Embryology, Faculty of Pharmacy, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Gréta Kis
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Zoltán Mészár
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary
| | - Zsuzsanna Bardóczi
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Miklós Antal
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary. .,MTA-DE Neuroscience Research Group, Nagyerdei krt. 98, 4012, Debrecen, Hungary.
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