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Kubíčková L, Klusáková I, Dubový P. Bilateral activation of glial cells and cellular distribution of the chemokine CCL2 and its receptor CCR2 in the trigeminal subnucleus caudalis of trigeminal neuropathic pain model. Histochem Cell Biol 2020; 153:239-255. [PMID: 32020274 DOI: 10.1007/s00418-020-01850-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2020] [Indexed: 12/26/2022]
Abstract
Glial cells activated by peripheral nerve injury contribute to the induction and maintenance of neuropathic pain by releasing neuromodulating cytokines and chemokines. We investigated the activation of microglia and astrocytes as well as the cellular distribution of the chemokine CCL2 and its receptor CCR2 in the trigeminal subnucleus caudalis (TSC) ipsilateral and contralateral to infraorbital nerve ligature (IONL). The left infraorbital nerve was ligated under aseptic conditions, and sham controls were operated without nerve ligature. Tactile hypersensitivity was significantly increased bilaterally in vibrissal pads of both sham- and IONL-operated animals from day 1 to 7 and tended to normalize in sham controls surviving for 14 days. Activated microglial cells significantly increased bilaterally in the TSC of both sham- and IONL-operated animals with a marked but gradual increase in the ipsilateral TSC from 1 to 7 days followed by a decrease by day 14. In contrast, robust activation of astrocytes was found bilaterally in the TSC of IONL-operated rats from 3 to 14 days with a transient activation in the ipsilateral TSC of sham-operated animals. Cellular distribution of CCL2 varied with survival time. CCL2 immunofluorescence was detected in neurons within 3 days and in astrocytes at later time points. In contrast, CCR2 was found only in astrocytes at all time points with CCR2 intensity being dominant in the ipsilateral TSC. In summary, our results reveal bilateral activation of microglial cells and astrocytes as well as changes in the cellular distribution of CCL2 and its receptor CCR2 in the TSC during the development and maintenance of orofacial neuropathic pain.
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Affiliation(s)
- Lucie Kubíčková
- Department of Anatomy, Cellular and Molecular Research Group, Faculty of Medicine, Masaryk University, Kamenice 3, 62500, Brno, Czech Republic
| | - Ilona Klusáková
- Department of Anatomy, Cellular and Molecular Research Group, Faculty of Medicine, Masaryk University, Kamenice 3, 62500, Brno, Czech Republic
| | - Petr Dubový
- Department of Anatomy, Cellular and Molecular Research Group, Faculty of Medicine, Masaryk University, Kamenice 3, 62500, Brno, Czech Republic.
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Dubový P, Klusáková I, Hradilová-Svíženská I, Brázda V, Kohoutková M, Joukal M. A Conditioning Sciatic Nerve Lesion Triggers a Pro-regenerative State in Primary Sensory Neurons Also of Dorsal Root Ganglia Non-associated With the Damaged Nerve. Front Cell Neurosci 2019; 13:11. [PMID: 30778286 PMCID: PMC6369159 DOI: 10.3389/fncel.2019.00011] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 01/14/2019] [Indexed: 12/19/2022] Open
Abstract
The primary sensory neurons of dorsal root ganglia (DRG) are a very useful model to study the neuronal regenerative program that is a prerequisite for successful axon regeneration after peripheral nerve injury. Seven days after a unilateral sciatic nerve injury by compression or transection, we detected a bilateral increase in growth-associated protein-43 (GAP-43) and superior cervical ganglion-10 (SCG-10) mRNA and protein levels not only in DRG neurons of lumbar spinal cord segments (L4-L5) associated with injured nerve, but also in remote cervical segments (C6-C8). The increase in regeneration-associated proteins in the cervical DRG neurons was associated with the greater length of regenerated axons 1 day after ulnar nerve crush following prior sciatic nerve injury as compared to controls with only ulnar nerve crush. The increased axonal regeneration capacity of cervical DRG neurons after a prior conditioning sciatic nerve lesion was confirmed by neurite outgrowth assay of in vitro cultivated DRG neurons. Intrathecal injection of IL-6 or a JAK2 inhibitor (AG490) revealed a role for the IL-6 signaling pathway in activating the pro-regenerative state in remote DRG neurons. Our results suggest that the pro-regenerative state induced in the DRG neurons non-associated with the injured nerve reflects a systemic reaction of these neurons to unilateral sciatic nerve injury.
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Affiliation(s)
- Petr Dubový
- Department of Anatomy, Laboratory of Cellular and Molecular Neurobiology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Ilona Klusáková
- Department of Anatomy, Laboratory of Cellular and Molecular Neurobiology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Ivana Hradilová-Svíženská
- Department of Anatomy, Laboratory of Cellular and Molecular Neurobiology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Václav Brázda
- Department of Anatomy, Laboratory of Cellular and Molecular Neurobiology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Marcela Kohoutková
- Department of Anatomy, Laboratory of Cellular and Molecular Neurobiology, Faculty of Medicine, Masaryk University, Brno, Czechia
| | - Marek Joukal
- Department of Anatomy, Laboratory of Cellular and Molecular Neurobiology, Faculty of Medicine, Masaryk University, Brno, Czechia
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Brázda V, Klusáková I, Hradilová Svíženská I, Dubový P. Dynamic response to peripheral nerve injury detected by in situ hybridization of IL-6 and its receptor mRNAs in the dorsal root ganglia is not strictly correlated with signs of neuropathic pain. Mol Pain 2013; 9:42. [PMID: 23953943 PMCID: PMC3844395 DOI: 10.1186/1744-8069-9-42] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 08/14/2013] [Indexed: 12/15/2022] Open
Abstract
Background IL-6 is a typical injury-induced mediator. Together with its receptors, IL-6 contributes to both induction and maintenance of neuropathic pain deriving from changes in activity of primary sensory neurons in dorsal root ganglia (DRG). We used in situ hybridization to provide evidence of IL-6 and IL-6 receptors (IL-6R and gp130) synthesis in DRG along the neuraxis after unilateral chronic constriction injury (CCI) of the sciatic nerve as an experimental model of neuropathic pain. Results All rats operated upon to create unilateral CCI displayed mechanical allodynia and thermal hyperalgesia in ipsilateral hind paws. Contralateral hind paws and forepaws of both sides exhibited only temporal and nonsignificant changes of sensitivity. Very low levels of IL-6 and IL-6R mRNAs were detected in naïve DRG. IL-6 mRNA was bilaterally increased not only in DRG neurons but also in satellite glial cells (SGC) activated by unilateral CCI. In addition to IL-6 mRNA, substantial increase of IL-6R mRNA expression occurred in DRG neurons and SGC following CCI, while the level of gp130 mRNA remained similar to that of DRG from naïve rats. Conclusions Here we evidence for the first time increased synthesis of IL-6 and IL-6R in remote cervical DRG nonassociated with the nerve injury. Our results suggest that unilateral CCI of the sciatic nerve induced not only bilateral elevation of IL-6 and IL-6R mRNAs in L4–L5 DRG but also their propagation along the neuraxis to remote cervical DRG as a general neuroinflammatory reaction of the nervous system to local nerve injury without correlation with signs of neuropathic pain. Possible functional involvement of IL-6 signaling is discussed.
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Affiliation(s)
- Václav Brázda
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 3, 62500, Brno, Czech Republic.
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Svízenská IH, Brázda V, Klusáková I, Dubový P. Bilateral changes of cannabinoid receptor type 2 protein and mRNA in the dorsal root ganglia of a rat neuropathic pain model. J Histochem Cytochem 2013; 61:529-47. [PMID: 23657829 DOI: 10.1369/0022155413491269] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cannabinoid receptor type 2 (CB2R) plays a critical role in nociception. In contrast to cannabinoid receptor type 1 ligands, CB2R agonists do not produce undesirable central nervous system effects and thus promise to treat neuropathic pain that is often resistant to medical therapy. In the study presented here, we evaluated the bilateral distribution of the CB2R protein and messenger RNA (mRNA) in rat dorsal root ganglia (DRG) after unilateral peripheral nerve injury using immunohistochemistry, western blot, and in situ hybridization analysis. Unilateral chronic constriction injury (CCI) of the sciatic nerve induced neuropathic pain behavior and bilateral elevation of both CB2R protein and mRNA in lumbar L4-L5 as well as cervical C7-C8 DRG when compared with naive animals. CB2R protein and mRNA were increased not only in DRG neurons but also in satellite glial cells. The fact that changes appear bilaterally and (albeit at a lower level) even in the remote cervical DRG can be related to propagation of neuroinflammation alongside the neuraxis and to the neuroprotective effects of CB2R.
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Dubový P, Brázda V, Klusáková I, Hradilová-Svíženská I. Bilateral elevation of interleukin-6 protein and mRNA in both lumbar and cervical dorsal root ganglia following unilateral chronic compression injury of the sciatic nerve. J Neuroinflammation 2013; 10:55. [PMID: 23634725 PMCID: PMC3657546 DOI: 10.1186/1742-2094-10-55] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 04/03/2013] [Indexed: 11/10/2022] Open
Abstract
Background Current research implicates interleukin (IL)-6 as a key component of the nervous-system response to injury with various effects. Methods We used unilateral chronic constriction injury (CCI) of rat sciatic nerve as a model for neuropathic pain. Immunofluorescence, ELISA, western blotting and in situ hybridization were used to investigate bilateral changes in IL-6 protein and mRNA in both lumbar (L4-L5) and cervical (C7-C8) dorsal root ganglia (DRG) following CCI. The operated (CCI) and sham-operated (sham) rats were assessed after 1, 3, 7, and 14 days. Withdrawal thresholds for mechanical hyperalgesia and latencies for thermal hyperalgesia were measured in both ipsilateral and contralateral hind and fore paws. Results The ipsilateral hind paws of all CCI rats displayed a decreased threshold of mechanical hyperalgesia and withdrawal latency of thermal hyperalgesia, while the contralateral hind and fore paws of both sides exhibited no significant changes in mechanical or thermal sensitivity. No significant behavioral changes were found in the hind and fore paws on either side of the sham rats, except for thermal hypersensitivity, which was present bilaterally at 3 days. Unilateral CCI of the sciatic nerve induced a bilateral increase in IL-6 immunostaining in the neuronal bodies and satellite glial cells (SGC) surrounding neurons of both lumbar and cervical DRG, compared with those of naive control rats. This bilateral increase in IL-6 protein levels was confirmed by ELISA and western blotting. More intense staining for IL-6 mRNA was detected in lumbar and cervical DRG from both sides of rats following CCI. The DRG removed from sham rats displayed a similar pattern of staining for IL-6 protein and mRNA as found in naive DRG, but there was a higher staining intensity in SGC. Conclusions Bilateral elevation of IL-6 protein and mRNA is not limited to DRG homonymous to the injured nerve, but also extended to DRG that are heteronymous to the injured nerve. The results for IL-6 suggest that the neuroinflammatory reaction of DRG to nerve injury is propagated alongside the neuroaxis from the lumbar to the remote cervical segments. This is probably related to conditioning of cervical DRG neurons to injury.
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Affiliation(s)
- Petr Dubový
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 3, Brno, 62500, Czech Republic.
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Satellite glial cells express IL-6 and corresponding signal-transducing receptors in the dorsal root ganglia of rat neuropathic pain model. ACTA ACUST UNITED AC 2010; 6:73-83. [DOI: 10.1017/s1740925x10000074] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
There is a growing body of evidence that cytokines contribute to both induction and maintenance of neuropathic pain derived from changes in dorsal root ganglia (DRG), including the activity of the primary sensory neurons and their satellite glial cells (SGC). We used immunofluorescence andin situhybridization methods to provide evidence that chronic constriction injury (CCI) of the sciatic nerve induces synthesis of interleukin-6 (IL-6) in SGC, elevation of IL-6 receptor (IL-6R) and activation of signal transducer and activator of transcription 3 (STAT3) signalling. Unilateral CCI of the rat sciatic nerve induced mechanoallodynia and thermal hyperalgesia in ipsilateral hind paws, but contralateral paws exhibited only temporal changes of sensitivity. We demonstrated that IL-6 mRNA and protein, which were expressed at very low levels in naïve DRG, were bilaterally increased not only in L4-L5 DRG neurons but also in SGC activated by unilateral CCI. Besides IL-6, substantial increase of IL-6R and pSTAT3 expression occurred in SGC following CCI, however, IL-6R associated protein, gp130 levels did not change. The results may suggest that unilateral CCI of the sciatic nerve induces bilateral activation of SGC in L4-L5 DRG to transduce IL-6 signalling during neuroinflammation.
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Brázda V, Klusáková I, Svíženská I, Veselková Z, Dubový P. Bilateral Changes in IL-6 Protein, but not in its Receptor gp130, in Rat Dorsal Root Ganglia Following Sciatic Nerve Ligature. Cell Mol Neurobiol 2009; 29:1053-62. [DOI: 10.1007/s10571-009-9396-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 03/16/2009] [Indexed: 01/19/2023]
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Puigdellívol-Sánchez A, Prats-Galino A, Molander C. Estimations of topographically correct regeneration to nerve branches and skin after peripheral nerve injury and repair. Brain Res 2006; 1098:49-60. [PMID: 16780817 DOI: 10.1016/j.brainres.2006.04.077] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Revised: 04/18/2006] [Accepted: 04/19/2006] [Indexed: 11/16/2022]
Abstract
Peripheral nerve injury is typically associated with long-term disturbances in sensory localization, despite nerve repair and regeneration. Here, we investigate the extent of correct reinnervation by back-labeling neuronal soma with fluorescent tracers applied in the target area before and after sciatic nerve injury and repair in the rat. The subpopulations of sensory or motor neurons that had regenerated their axons to either the tibial branch or the skin of the third hindlimb digit were calculated from the number of cell bodies labeled by the first and/or second tracer. Compared to the normal control side, 81% of the sensory and 66% of the motor tibial nerve cells regenerated their axons back to this nerve, while 22% of the afferent cells from the third digit reinnervated this digit. Corresponding percentages based on quantification of the surviving population on the experimental side showed 91%, 87%, and 56%, respectively. The results show that nerve injury followed by nerve repair by epineurial suture results in a high but variable amount of topographically correct regeneration, and that proportionally more neurons regenerate into the correct proximal nerve branch than into the correct innervation territory in the skin.
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Affiliation(s)
- Anna Puigdellívol-Sánchez
- Department of Human Anatomy and Embryology, Faculty of Medicine, University of Barcelona, 08036 Barcelona, Spain
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Osamura N, Ikeda K, Ito T, Higashida H, Tomita K, Yokoyama S. Induction of interleukin-6 in dorsal root ganglion neurons after gradual elongation of rat sciatic nerve. Exp Neurol 2005; 195:61-70. [PMID: 15913608 DOI: 10.1016/j.expneurol.2005.03.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 03/25/2005] [Accepted: 03/30/2005] [Indexed: 11/22/2022]
Abstract
In the reconstruction of a segmental defect in injured peripheral nerves, gradual nerve elongation has become an important alternative to nerve grafting. To clarify biochemical responses in peripheral sensory neurons after nerve elongation, we examined the expression of cytokines and neurotrophins related to nerve regeneration. We first established rat elongation models by lengthening left femurs up to 20.0 mm at the rate of 1.0, 2.0, or 20.0 mm/day. In toluidine blue staining, the acutely elongated, 20-mm/day group showed nuclear eccentricity in the nerve cell body in L5 dorsal root ganglion (DRG) and axonal degeneration in the sciatic nerves; in contrast, the gradually elongated, 1- and 2-mm/day groups remained intact, indicating adaptation. Reverse transcription-polymerase chain reaction analysis revealed that interleukin-6 (IL-6) mRNA was induced in ipsilateral L4-6 DRG in an elongation rate-dependent manner. In contrast, none of the elongated groups exhibited a significant change in mRNA levels for interleukin-1beta, tumor necrosis factor-alpha, nerve growth factor, brain-derived neurotrophic factor, neurotropnin-3, and neurotrophin-4/5. Levels of IL-6 mRNA in all the elongated groups reached the maximum level at day 4 after 20-mm lengthening, while the axotomized group showed a decrease from the maximum level at day 1. Induction of IL-6 mRNA was also detected in the contralateral L4-6 DRG of all the elongated groups, but not detected in the axotomized group. In histochemical analysis, IL-6-immunoreactivity was predominant in neurofilament-positive, medium to large DRG neurons. Application of IL-6 to cultured Schwann cells increased mRNA for peripheral myelin protein 22 (PMP22), a major myelin component. These results suggest that IL-6 plays a key role in biochemical responses in peripheral sensory neurons after gradual nerve elongation.
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Affiliation(s)
- Naoki Osamura
- Department of Orthopaedic Surgery, School of Medicine, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-8641, Japan.
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Renton T, Thexton A, McGurk M. Objective evaluation of iatrogenic lingual nerve injuries using the jaw-opening reflex. Br J Oral Maxillofac Surg 2005; 43:232-7. [PMID: 15888359 DOI: 10.1016/j.bjoms.2004.11.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2004] [Indexed: 12/12/2022]
Abstract
The extent of reflex inhibition of masseteric electromyographic activity, after an electrical stimulus applied to lingual mucosa, was used as a test of the ability of the lingual nerve to conduct nerve impulses and this was compared with the results of standard clinical tests. Two groups of subjects were assessed: healthy subjects (n=10) and patients with lingual nerve injuries (n=17). The patients were tested 8-9 weeks after their injury and retested 6 months later when they were retrospectively allocated to either a temporary injury or a permanent injury group. The group measure of reflex inhibition after stimulation of the tongue on the opposite side to the injury was no different from the same measure in controls, whereas two-point discrimination did differ. Group measures of inhibition and of subjective function after stimulation on the side of the injury were significantly different from controls whereas light touch and two-point discrimination were not. There was good agreement between quantified masseteric inhibition and subjective function, but it was not possible at 8-9 weeks after the injury to differentiate between those that would recover and those that would be permanent.
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Affiliation(s)
- T Renton
- Department of Oral and Maxillofacial Surgery, Queen Mary's University School of Medicine and Dentistry, Turner Street, London E1 2AD, UK.
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Ruohonen S, Jagodi M, Khademi M, Taskinen HS, Ojala P, Olsson T, Röyttä M. Contralateral non-operated nerve to transected rat sciatic nerve shows increased expression of IL-1beta, TGF-beta1, TNF-alpha, and IL-10. J Neuroimmunol 2002; 132:11-7. [PMID: 12417428 DOI: 10.1016/s0165-5728(02)00281-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent reports indicate that after a peripheral nerve injury, the uninjured contralateral nerve is also affected. Because cytokines play an important role in the peripheral nerve injury, we studied the expression of five different mRNAs (interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-10 (IL-10), transforming growth factor-beta1 (TGF-beta1) and interleukin-4 (IL-4)) in the contralateral, non-operated, left sciatic nerve when the right rat sciatic nerve was transected. This study extended up to 42 days after the transection. No IL-4 expression was noted. During the first 3 days, high expression of the other studied cytokines was noted in the endoneurium. At day 7, the expression diminished to the control levels. After this, a cyclic expression pattern appeared, which was most pronounced in the endoneurium at 35 days. We also show that the expression pattern in the endoneurium is different from that in the surrounding epi- and perineurium. Also, our present study shows clearly that contralateral nerves are poor controls after injury.
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Affiliation(s)
- Saku Ruohonen
- Department of Pathology, University of Turku, Kiinanmyllynkatu 10, FIN-20520 Turku, Finland
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Benoliel R, Wilensky A, Tal M, Eliav E. Application of a pro-inflammatory agent to the orbital portion of the rat infraorbital nerve induces changes indicative of ongoing trigeminal pain. Pain 2002; 99:567-578. [PMID: 12406533 DOI: 10.1016/s0304-3959(02)00272-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The present experiments investigated the behavioral and immunocytchemical (ICC) effects of applying complete Freund's adjuvant (CFA) to the orbital portion of the infraorbital nerve (IOn). Two control groups, the first had saline applied to the IOn and the second underwent sham operation, were included in the study. In the CFA group, significant hyper-responsiveness to von Frey (analysis of variance <0.05) and to pinprick stimulation (Kruskal Wallis <0.05) in the vibrissal pad was observed on the fourth and the fifth days post-operative (dpo). This was accompanied by a reduced bite force and altered bite patterns of similar duration. Histology of the IOn in CFA rats revealed immune cell infiltration and edema around and in the nerve trunk with only mild axonal damage confirmed by neuropeptide Y immunoreactivity in trigeminal ganglion. Histological areas of inconsistent and mild inflammation were observed in the saline group that were accompanied by similarly attenuated behavioral and ICC changes. This model of inflammation-induced neuropathic pain is highly applicable to the study of neuroinflammatory orofacial pain.
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Affiliation(s)
- Rafael Benoliel
- The Department of Oral Diagnosis, Oral Medicine, Oral Radiology, Hadassah School of Dental Medicine, The Hebrew University,Jerusalem, Israel The Department of Anatomy, Hadassah School of Dental Medicine, The Hebrew University, Jerusalem, Israel
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Anderson LC, Rao RD. Interleukin-6 and nerve growth factor levels in peripheral nerve and brainstem after trigeminal nerve injury in the rat. Arch Oral Biol 2001; 46:633-40. [PMID: 11369318 DOI: 10.1016/s0003-9969(01)00024-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Earlier studies have demonstrated that inflammation plays a role in the development of evoked pain following partial nerve injury. In this report, we demonstrate bilateral changes in interleukin-6 (IL-6) and nerve growth factor (nerve growth factor) levels following unilateral infraorbital nerve (infraorbital nerve) constriction. infraorbital nerve constriction resulted in an initial period of decreased mechanical sensitivity (1 and 3 days), followed by recovery (7 days) and then a marked bilateral mechanical hypersensitivity (10 and 28 days). nerve growth factor levels in the injured infraorbital nerve were elevated on all days, but peak concentrations of nerve growth factor were observed on day 3. A smaller increase was also observed on days 1, 3, and 7 in the uninjured nerve. A bilateral elevation of IL-6 was also seen on days 3 and 10 in the infraorbital nerve, and in the brainstem on days 3, 7 and 10 after constriction. No changes in mechanical sensitivity were found after a sham-injury, but there was a small increase in brainstem IL-6 ipsilaterally at 7 days. We conclude from these data that increases in IL-6 and nerve growth factor may contribute to the development of mechanical allodynia after trigeminal nerve injury, but they are not specifically correlated with the onset or duration of pain behaviors.
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Affiliation(s)
- L C Anderson
- Department of Anatomy, School of Dentistry, University of the Pacific, 2155 Webster Street, San Francisco, CA 94115, USA.
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Ryoke K, Ochi M, Iwata A, Uchio Y, Yamamoto S, Yamaguchi H. A conditioning lesion promotes in vivo nerve regeneration in the contralateral sciatic nerve of rats. Biochem Biophys Res Commun 2000; 267:715-8. [PMID: 10673357 DOI: 10.1006/bbrc.1999.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A conditioning lesion in the sciatic nerve increases in vivo axonal regeneration in the nerve after a second transection. We studied whether this increased regeneration also occurs in the contralateral nerve. The left sciatic nerve was transected and sutured in Wistar rats; the nerve was exposed but not transected in controls. After 5 days, the right sciatic nerves of all rats were transected and sutured. Neuronal regeneration was measured at 0, 1, 3, 5, and 7 days with the pinch test and histological staining. IL-1beta and TGF-beta1 expression was also measured. The initial delay in the experimental group was significantly shorter, but the regeneration rates were the same. The expression of IL-1beta and TGF-beta1 in the right dorsal root ganglia was significantly higher in the experimental group. Nerve injury enhances cytokine expression in the contralateral dorsal root ganglion and promotes contralateral nerve regeneration in vivo by shortening the initial delay.
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Affiliation(s)
- K Ryoke
- Department of Orthopaedics, Shimane Medical University, 89-1 Enya-cho, Izumo, Shimane-ken, 693-8501, Japan
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