1
|
Moattari CR, Granstein RD. Neuropeptides and neurohormones in immune, inflammatory and cellular responses to ultraviolet radiation. Acta Physiol (Oxf) 2021; 232:e13644. [PMID: 33724698 DOI: 10.1111/apha.13644] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 12/16/2022]
Abstract
Humans are exposed to varying amounts of ultraviolet radiation (UVR) through sunlight. UVR penetrates into human skin leading to release of neuropeptides, neurotransmitters and neuroendocrine hormones. These messengers released from local sensory nerves, keratinocytes, Langerhans cells (LCs), mast cells, melanocytes and endothelial cells (ECs) modulate local and systemic immune responses, mediate inflammation and promote differing cell biologic effects. In this review, we will focus on both animal and human studies that elucidate the roles of calcitonin gene-related peptide (CGRP), substance P (SP), nerve growth factor (NGF), nitric oxide and proopiomelanocortin (POMC) derivatives in mediating immune and inflammatory effects of exposure to UVR as well as other cell biologic effects of UVR exposure.
Collapse
|
2
|
La Russa F, Lopes DM, Hobbs C, Argunhan F, Brain S, Bevan S, Bennett DLH, McMahon SB. Disruption of the Sensory System Affects Sterile Cutaneous Inflammation In Vivo. J Invest Dermatol 2019; 139:1936-1945.e3. [PMID: 30974165 DOI: 10.1016/j.jid.2019.01.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 01/11/2019] [Accepted: 01/12/2019] [Indexed: 01/09/2023]
Abstract
Increasing evidence suggests that nerve fibers responding to noxious stimuli (nociceptors) modulate immunity in a variety of tissues, including the skin. Yet, the role of nociceptors in regulating sterile cutaneous inflammation remains unexplored. To address this question, we have developed a detailed description of the sterile inflammation caused by overexposure to UVB irradiation (i.e., sunburn) in the mouse plantar skin. Using this model, we observed that chemical depletion of nociceptor terminals did not alter the early phase of the inflammatory response to UVB, but it caused a significant increase in the number of dendritic cells and αβ+ T cells as well as enhanced extravasation during the later stages of inflammation. Finally, we showed that such regulation was driven by the nociceptive neuropeptide calcitonin gene-related peptide. In conclusion, we propose that nociceptors not only play a crucial role in inflammation through avoidance reflexes and behaviors, but can also regulate sterile cutaneous immunity in vivo.
Collapse
Affiliation(s)
- Federica La Russa
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom.
| | - Douglas M Lopes
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Carl Hobbs
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Fulye Argunhan
- School of Cardiovascular Medicine and Sciences, King's College London, London, United Kingdom
| | - Susan Brain
- School of Cardiovascular Medicine and Sciences, King's College London, London, United Kingdom
| | - Stuart Bevan
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - David L H Bennett
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Stephen B McMahon
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| |
Collapse
|
3
|
Chidiac JJ, Kassab A, Rifai K, Al-Chaer ED, Saadé NE. Contribution of capsaicin-sensitive innervation to the continuous eruption of the rat mandibular incisors. Anat Sci Int 2018; 94:136-143. [PMID: 30229540 DOI: 10.1007/s12565-018-0460-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 09/10/2018] [Indexed: 12/20/2022]
Abstract
A major component of tooth innervation is made of capsaicin-sensitive primary afferents (CSPA). These fibers play a key role in tooth pain and inflammation; little is known, however, about the role of CSPA in tooth eruption. The aim of this study was to examine the role of the capsaicin-sensitive afferents in the process of eruption of intact rat incisors. CSPA fibers in several rat groups, were subjected to one of the following experimental procedures: systemic chemical ablation, systemic ablation followed by chemical sympathectomy and localized activation. The observed effects on incisor eruption were compared to those made on controls. The total amount of eruption in control/naïve rats, measured over a total period of 144 h, was 3.18 ± 0.07 mm and decreased to 2.43 ± 0.08 mm (n = 7; p < 0.001) following systemic ablation of CSPA. Further decrease to 2.24 ± 0.08 mm (n = 7; p < 0.001) was noticed when chemical sympathectomy was added to CSPA ablation. The average rate of eruption was 1.7 ± 0.25 mm following CSPA activation, compared to an average of 0.8 ± 0.07 mm for controls (n = 7; p < 0.001). Capsaicin sensitive fibers play an important role in tooth homeostasis, and intact neural supply is required for tooth growth under normal conditions.
Collapse
Affiliation(s)
| | - Ammar Kassab
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Khaldoun Rifai
- School of Dentistry, Lebanese University, Beirut, Lebanon
| | - Elie D Al-Chaer
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Nayef E Saadé
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| |
Collapse
|
4
|
Painful stimulation of a sensitized site in the forearm inhibits ipsilateral trigeminal nociceptive blink reflexes. Exp Brain Res 2018; 236:2097-2105. [PMID: 29754196 DOI: 10.1007/s00221-018-5255-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 04/06/2018] [Indexed: 10/16/2022]
Abstract
Exposure to moderate levels of ultraviolet B radiation (UVB) is painless but nevertheless induces an inflammatory response that sensitizes primary afferent nociceptors. Subsequently, heating the UVB-treated site can sensitize spinal nociceptors. We used a repeated-measures design to determine whether heating the UVB-treated site also triggers ipsilateral inhibitory controls. Specifically, a 2-cm diameter site on the forearm of 20 participants was exposed to UVB at twice the minimum erythema dose. 48 h later mechanical and thermal sensitivity had increased at the UVB-treated site, indicating primary hyperalgesia. In addition, sensitivity to blunt pressure had increased in the ipsilateral forehead, implying activation of an ipsilateral supra-spinal pro-nociceptive mechanism. Despite this, the area under the curve of the ipsilateral nociceptive blink reflex decreased when the UVB-treated site was heated to induce moderate pain. Together, these findings suggest that the UVB treatment sensitized primary nociceptive afferents and generated an ipsilateral supra-spinal pro-nociceptive mechanism. In addition, sensitization to heat induced by the UVB treatment strengthened an ipsilateral anti-nociceptive process elicited by heat-pain. Infrequent but enduring discharge of sensitized primary nociceptive afferents, driven by inflammation after UVB exposure, might initiate a lateralized supra-spinal pro-nociceptive influence that heightens awareness of impending harm on the sensitized side of the body. In addition, a lateralized anti-nociceptive response triggered by an intense barrage of nociceptive signals may help to differentiate stronger from weaker sources of pain.
Collapse
|
5
|
Chidiac JJ, Kassab A, Rifai K, Saadé NE, Al Chaer ED. Modulation of incisor eruption in rats by sympathetic efferents. Arch Oral Biol 2018; 89:31-36. [PMID: 29432940 DOI: 10.1016/j.archoralbio.2018.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 01/17/2018] [Accepted: 02/04/2018] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Intact neural supply is necessary for tooth eruption. Sympathetic denervation accelerates or decelerates the eruption rate depending on the tooth condition (intact or injured). The aim of this study is to reexamine the role of the sympathetic innervation, through the observation of the effects of pre or post ganglionic chemical sympathectomy on the eruption of intact rat incisors. MATERIALS AND METHODS Different groups of rats were subjected to either ganglionic or peripheral chemical sympathectomy and the observed effects on incisor eruption were compared to those made on intact/sham groups or on rats subjected to inferior alveolar nerve (IAN) lesion. RESULTS The total amount of eruption in control/naïve rats, measured over a total period of 144 h, was 3 ± 0.15 mm and decreased to 2.57 ± 0.06 mm (n = 8; p < 0.01) or 2.8 ± 0.10 mm (n = 8; p < 0.05) following treatment with guanethidine and hexamethonium, respectively. This amount decreased to 1.8 ± 0.14 mm (p < 0.001 vs. control, n = 7; or p < 0.01 vs. sham, n = 5) in rats subjected to IAN lesion. CONCLUSION Sympathectomy delayed tooth eruption. Blocking the sympathetic effectors with guanethidine exerted more potent effects than ganglionic block with hexamethonium. Intact sympathetic supply is required for tooth growth under normal conditions.
Collapse
Affiliation(s)
- José Johann Chidiac
- Department of Prosthodontics, School of Dentistry, Lebanese University, Lebanon.
| | - Ammar Kassab
- Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut, Lebanon
| | - Khaldoun Rifai
- Department of Prosthodontics, School of Dentistry, Lebanese University, Lebanon
| | - Nayef E Saadé
- Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut, Lebanon
| | - Elie D Al Chaer
- Department of Anatomy, Cell Biology and Physiology, Faculty of Medicine, American University of Beirut, Lebanon
| |
Collapse
|
6
|
Abstract
Supplemental Digital Content is Available in the Text. A novel and potent protein kinase G-1α (PKG-1α) inhibitor is used to demonstrate the important roles of PKG in capsaicin-induced acute pain and in persistent inflammatory pain. Activating PKG-1α induces a long-term hyperexcitability (LTH) in nociceptive neurons. Since the LTH correlates directly with chronic pain in many animal models, we tested the hypothesis that inhibiting PKG-1α would attenuate LTH-mediated pain. We first synthesized and characterized compound N46 (N-((3R,4R)-4-(4-(2-fluoro-3-methoxy-6-propoxybenzoyl)benzamido)pyrrolidin-3-yl)-1H-indazole-5-carboxamide). N46 inhibits PKG-1α with an IC50 of 7.5 nmol, was highly selective when tested against a panel of 274 kinases, and tissue distribution studies indicate that it does not enter the CNS. To evaluate its antinociceptive potential, we used 2 animal models in which the pain involves both activated PKG-1α and LTH. Injecting complete Freund's adjuvant (CFA) into the rat hind paw causes a thermal hyperalgesia that was significantly attenuated 24 hours after a single intravenous injection of N46. Next, we used a rat model of osteoarthritic knee joint pain and found that a single intra-articular injection of N46 alleviated the pain 14 days after the pain was established and the relief lasted for 7 days. Thermal hyperalgesia and osteoarthritic pain are also associated with the activation of the capsaicin-activated transient receptor protein vanilloid-1 (TRPV1) channel. We show that capsaicin activates PKG-1α in nerves and that a subcutaneous delivery of N46 attenuated the mechanical and thermal hypersensitivity elicited by exposure to capsaicin. Thus, PKG-1α appears to be downstream of the transient receptor protein vanilloid-1. Our studies provide proof of concept in animal models that a PKG-1α antagonist has a powerful antinociceptive effect on persistent, already existing inflammatory pain. They further suggest that N46 is a valid chemotype for the further development of such antagonists.
Collapse
|
7
|
Etemadi L, Pettersson LME, Danielsen N. UVB irradiation induces rapid changes in galanin, substance P and c-fos immunoreactivity in rat dorsal root ganglia and spinal cord. Peptides 2017; 87:71-83. [PMID: 27923581 DOI: 10.1016/j.peptides.2016.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 11/29/2016] [Accepted: 12/01/2016] [Indexed: 12/13/2022]
Abstract
Recent studies have shown that UVB irradiation induces primary and secondary hyperalgesia in rats and humans peaking about 24h after UVB exposure. In the present study we investigated the changes in galanin, substance P and c-fos immunoreactivity in rat DRG and spinal cord at the L5 level 2-96h after UVB irradiation. UVB irradiation of the heel area in rats almost increased the skin blood flow two-fold 24h after irradiation as measured by laser Doppler technique. UVB irradiation induced a significant reduction of the proportion of galanin positive DRG neurons for all time points, except at 12h. In the spinal cord, UVB irradiation induced increased immunoreactivity for galanin in the dorsal horn, the area around the central canal and interestingly also in the lateral spinal nucleus 12-96h after exposure. For substance P the proportion of substance P positive neurons was unchanged but UVB irradiation induced increased substance P immunoreactivity in the dorsal part of the spinal cord 48h after irradiation. UVB irradiation also induced c-fos immunoreactivity in the dorsal horn and the area around the central canal 24 and 48h after exposure. This translational model of UVB irradiation will induce rapid changes of neuropeptides implicated in nociceptive signaling in areas known to be of importance for nociception in a time frame, about 24h after exposure, where also neurophysiological alteration have been described in humans and rats.
Collapse
Affiliation(s)
- Leila Etemadi
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden.
| | - Lina M E Pettersson
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Nils Danielsen
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| |
Collapse
|
8
|
Ljungquist B, Jensen T, Etemadi L, Thelin J, Lind G, Garwicz M, Petersson P, Tsanakalis F, Schouenborg J. Discrepancies between cortical and behavioural long-term readouts of hyperalgesia in awake freely moving rats. Eur J Pain 2016; 20:1689-1699. [PMID: 27146646 PMCID: PMC5096034 DOI: 10.1002/ejp.892] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2016] [Indexed: 01/03/2023]
Abstract
BACKGROUND It is still unclear to what extent the most common animal models of pain and analgesia, based on indirect measures such as nocifensive behaviours, provide valid measures of pain perception. METHODS To address this issue, we developed a novel animal model comprising a more direct readout via chronically (>1 month) implanted multichannel electrodes (MCE) in rat primary somatosensory cortex (S1; known to be involved in pain perception in humans) and compared this readout to commonly used behavioural pain-related measures during development of hyperalgesia. A translational method to induce hyperalgesia, UVB irradiation of the skin, was used. Localized CO2 laser stimulation was made of twenty skin sites (20 stimulations/site/observation day) on the plantar hind paw, before and during the time period when enhanced pain perception is reported in humans after UVB irradiation. RESULTS We demonstrate a 2-10 fold significant enhancement of cortical activity evoked from both irradiated and adjacent skin and a time course that corresponds to previously reported enhancement of pain magnitude during development of primary and secondary hyperalgesia in humans. In contrast, withdrawal reflexes were only significantly potentiated from the irradiated skin area and this potentiation was significantly delayed as compared to activity in S1. CONCLUSIONS The present findings provide direct evidence that chronic recordings in S1 in awake animals can offer a powerful, and much sought for, translational model of the perception of pain magnitude during hyperalgesia. WHAT DOES THIS STUDY ADD?: In a novel animal model, chronic recordings of nociceptive activity in primary somatosensory cortex (S1) in awake freely moving rats are compared to behavioural readouts during UVB-induced hyperalgesia. Evoked activity in rat S1 replicates altered pain perception in humans during development of hyperalgesia, but withdrawal reflexes do not.
Collapse
Affiliation(s)
- B Ljungquist
- Neuronano Research Centre, Section for Neurophysiology, Lund University, Sweden
| | - T Jensen
- Neuronano Research Centre, Section for Neurophysiology, Lund University, Sweden
| | - L Etemadi
- Neuronano Research Centre, Section for Neurophysiology, Lund University, Sweden
| | - J Thelin
- Neuronano Research Centre, Section for Neurophysiology, Lund University, Sweden
| | - G Lind
- Neuronano Research Centre, Section for Neurophysiology, Lund University, Sweden
| | - M Garwicz
- Neuronano Research Centre, Section for Neurophysiology, Lund University, Sweden
| | - P Petersson
- Neuronano Research Centre, Section for Neurophysiology, Lund University, Sweden
| | - F Tsanakalis
- Neuronano Research Centre, Section for Neurophysiology, Lund University, Sweden
| | - J Schouenborg
- Neuronano Research Centre, Section for Neurophysiology, Lund University, Sweden.
| |
Collapse
|
9
|
Romano I, Summa M, Heredia-Guerrero JA, Spanò R, Ceseracciu L, Pignatelli C, Bertorelli R, Mele E, Athanassiou A. Fumarate-loaded electrospun nanofibers with anti-inflammatory activity for fast recovery of mild skin burns. ACTA ACUST UNITED AC 2016; 11:041001. [PMID: 27481333 DOI: 10.1088/1748-6041/11/4/041001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In the biomedical sector the availability of engineered scaffolds and dressings that control and reduce inflammatory states is highly desired, particularly for the management of burn wounds. In this work, we demonstrate for the first time, to the best of our knowledge, that electrospun fibrous dressings of poly(octyl cyanoacrylate) (POCA) combined with polypropylene fumarate (PPF) possess anti-inflammatory activity and promote the fast and effective healing of mild skin burns in an animal model. The fibers produced had an average diameter of (0.8 ± 0.1) µm and they were able to provide a conformal coverage of the injured tissue. The application of the fibrous mats on the burned tissue effectively reduced around 80% of the levels of pro-inflammatory cytokines in the first 48 h in comparison with un-treated animals, and enhanced skin epithelialization. From histological analysis, the skin thickness of the animals treated with POCA : PPF dressings appeared similar to that of one of the naïve animals: (13.7 ± 1.4) µm and (14.3 ± 2.5) µm for naïve and treated animals, respectively. The density of dermal cells was comparable as well: (1100 ± 112) cells mm(-2) and (1358 ± 255) cells mm(-2) for naïve and treated mice, respectively. The results demonstrate the suitability of the electrospun dressings in accelerating and effectively promoting the burn healing process.
Collapse
Affiliation(s)
- I Romano
- Smart Materials, Nanophysics, Istituto Italiano di Tecnologia, Via Morego 30, Genoa 16163, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Lopes DM, McMahon SB. Ultraviolet Radiation on the Skin: A Painful Experience? CNS Neurosci Ther 2015; 22:118-26. [PMID: 26331607 PMCID: PMC4833175 DOI: 10.1111/cns.12444] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 07/21/2015] [Accepted: 07/22/2015] [Indexed: 12/31/2022] Open
Abstract
Excessive exposure of skin to ultraviolet radiation (UVR) has dramatic clinical effects in humans, and it is a significant public health concern. Discomfort and sensory changes caused by skin sunburn are the main common features experienced by many of us, a phenomena triggered by the combination of long and short wavelengths radiation (UVA and UVB, respectively). Although the biological processes underlying UVR exposure are not fully understood, in the last few years many studies have made significant progress in characterizing sunburn at the cellular and molecular levels, making use of both humans and laboratory animal models. Here we review and reason that UVR can be used as an excellent model of sensitization and inflammation for pain research. UVR, particularly UVB, produces a controllable and sterile inflammation that causes a robust dose‐dependent hypersensitivity with minimal confounding effects. Importantly, we show that UVR animal models precisely recapitulate the sensory, cellular, and molecular changes observed in human skin, giving it great confidence as a translational model. Furthermore, in this article, we give an overview of the pharmacology underlying UVB inflammation, the latest advances in the field, and potential new targets for inflammatory pain.
Collapse
Affiliation(s)
- Douglas M Lopes
- Neurorestoration group, Wolfson Centre for Age-Related Diseases, King's College London, London, UK
| | - Stephen B McMahon
- Neurorestoration group, Wolfson Centre for Age-Related Diseases, King's College London, London, UK
| |
Collapse
|
11
|
O'Neill J, Sikandar S, McMahon SB, Dickenson AH. Human psychophysics and rodent spinal neurones exhibit peripheral and central mechanisms of inflammatory pain in the UVB and UVB heat rekindling models. J Physiol 2015; 593:4029-42. [PMID: 26047369 DOI: 10.1113/jp270294] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 06/03/2015] [Indexed: 01/19/2023] Open
Abstract
Translational research is key to bridging the gaps between preclinical findings and the patients, and a translational model of inflammatory pain will ideally induce both peripheral and central sensitisation, more effectively mimicking clinical pathophysiology in some chronic inflammatory conditions. We conducted a parallel investigation of two models of inflammatory pain, using ultraviolet B (UVB) irradiation alone and UVB irradiation with heat rekindling. We used rodent electrophysiology and human quantitative sensory testing to characterise nociceptive processing in the peripheral and central nervous systems in both models. In both species, UVB irradiation produces peripheral sensitisation measured as augmented evoked activity of rat dorsal horn neurones and increased perceptual responses of human subjects to mechanical and thermal stimuli. In both species, UVB with heat rekindling produces central sensitisation. UVB irradiation alone and UVB with heat rekindling are translational models of inflammation that produce peripheral and central sensitisation, respectively. The predictive value of laboratory models for human pain processing is crucial for improving translational research. The discrepancy between peripheral and central mechanisms of pain is an important consideration for drug targets, and here we describe two models of inflammatory pain that involve ultraviolet B (UVB) irradiation, which can employ peripheral and central sensitisation to produce mechanical and thermal hyperalgesia in rats and humans. We use electrophysiology in rats to measure the mechanically- and thermally-evoked activity of rat spinal neurones and quantitative sensory testing to assess human psychophysical responses to mechanical and thermal stimulation in a model of UVB irradiation and in a model of UVB irradiation with heat rekindling. Our results demonstrate peripheral sensitisation in both species driven by UVB irradiation, with a clear mechanical and thermal hypersensitivity of rat dorsal horn neurones and enhanced perceptual responses of human subjects to both mechanical and thermal stimulation. Additional heat rekindling produces markers of central sensitisation in both species, including enhanced receptive field sizes. Importantly, we also showed a correlation in the evoked activity of rat spinal neurones to human thermal pain thresholds. The parallel results in rats and humans validate the translational use of both models and the potential for such models for preclinical assessment of prospective analgesics in inflammatory pain states.
Collapse
Affiliation(s)
- Jessica O'Neill
- Department of Neuroscience, Physiology and Pharmacology, University College London, UK
| | - Shafaq Sikandar
- Wolfson Institute of Biomedical Research, University College London, UK
| | | | - Anthony H Dickenson
- Department of Neuroscience, Physiology and Pharmacology, University College London, UK
| |
Collapse
|
12
|
Weerasinghe NS, Lumb BM, Apps R, Koutsikou S, Murrell JC. Objective validation of central sensitization in the rat UVB and heat rekindling model. Eur J Pain 2014; 18:1199-206. [PMID: 24590815 PMCID: PMC4232048 DOI: 10.1002/j.1532-2149.2014.00469.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2014] [Indexed: 01/29/2023]
Abstract
Background The UVB and heat rekindling (UVB/HR) model shows potential as a translatable inflammatory pain model. However, the occurrence of central sensitization in this model, a fundamental mechanism underlying chronic pain, has been debated. Face, construct and predictive validity are key requisites of animal models; electromyogram (EMG) recordings were utilized to objectively demonstrate validity of the rat UVB/HR model. Methods The UVB/HR model was induced on the heel of the hind paw under anaesthesia. Mechanical withdrawal thresholds (MWTs) were obtained from biceps femoris EMG responses to a gradually increasing pinch at the mid hind paw region under alfaxalone anaesthesia, 96 h after UVB irradiation. MWT was compared between UVB/HR and SHAM-treated rats (anaesthetic only). Underlying central mechanisms in the model were pharmacologically validated by MWT measurement following intrathecal N-methyl-d-aspartate (NMDA) receptor antagonist, MK-801, or saline. Results Secondary hyperalgesia was confirmed by a significantly lower pre-drug MWT {mean [±standard error of the mean (SEM)]} in UVB/HR [56.3 (±2.1) g/mm2, n = 15] compared with SHAM-treated rats [69.3 (±2.9) g/mm2, n = 8], confirming face validity of the model. Predictive validity was demonstrated by the attenuation of secondary hyperalgesia by MK-801, where mean (±SEM) MWT was significantly higher [77.2 (±5.9) g/mm2n = 7] in comparison with pre-drug [57.8 (±3.5) g/mm2n = 7] and saline [57.0 (±3.2) g/mm2n = 8] at peak drug effect. The occurrence of central sensitization confirmed construct validity of the UVB/HR model. Conclusions This study used objective outcome measures of secondary hyperalgesia to validate the rat UVB/HR model as a translational model of inflammatory pain. What's already known about this topic? What does this study add?
Collapse
Affiliation(s)
- N S Weerasinghe
- School of Physiology and Pharmacology, University of Bristol, UK
| | | | | | | | | |
Collapse
|
13
|
Safieh-Garabedian B, Oz M, Bey RM, Shamaa F, Ashoor A, El-Agnaf OM, Saadé NE. Involvement of the α7-nicotinic acetylcholine receptors in the anti-inflammatory action of the thymulin-related peptide (PAT). Neuroscience 2013; 250:455-66. [PMID: 23880090 DOI: 10.1016/j.neuroscience.2013.07.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/11/2013] [Accepted: 07/14/2013] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND PURPOSE Peptide analog of thymulin (PAT) has been shown to have anti-hyperalgesic and anti-inflammatory properties in animal models of inflammation. Recent reports suggest that the peripheral cholinergic system has an anti-inflammatory role mediated by α7-nicotinic acetylcholine receptor (α7-nAChR). Our aim is to investigate whether the action of PAT is mediated, via the cholinergic pathway. EXPERIMENTAL APPROACH The anti-hyperalgesic and anti-inflammatory action of PAT was assessed in rat models of inflammatory nociceptive hyperactivity (carrageenan and endotoxin) and in a mice air-pouch model for localized inflammation, respectively; the possible attenuation of PAT's effects by pretreatment with the α7-nAchR specific antagonist methyllycaconitine citrate (MLA) was also investigated. In another series of experiments, using two electrode recordings, the effect of PAT on the α7-nAChRs, expressed in Xenopus Oocytes, was also determined. KEY RESULTS Administration of PAT reversed inflammatory nociceptive hyperactivity and cold and tactile hyperactivity in rats. This effect was partially or totally prevented by MLA, as assessed by different behavioral pain tests. Treatment with PAT also reduced the alteration of cytokines and NGF levels by carrageenan injection in the mouse air pouch model; this effect was partially antagonized by MLA. Electrophysiological recording demonstrated that PAT significantly potentiated the α7-nAchR expressed in Xenopus Oocytes. These effects were not observed when a control peptide, with a reverse sequence (rPAT), was utilized. CONCLUSIONS AND IMPLICATIONS The behavioral and electrophysiological observations described in this report demonstrate that PAT mediates, at least partially, its anti-inflammatory action by potentiating the α7-nAChR. These results indicate that PAT has a potential for new therapeutic applications as anti-inflammatory and analgesic agent.
Collapse
Affiliation(s)
- B Safieh-Garabedian
- Department of Natural Sciences and Public Health, Zayed University, Abu Dhabi, United Arab Emirates.
| | | | | | | | | | | | | |
Collapse
|
14
|
Di Giminiani P, Petersen LJ, Herskin MS. Characterization of nociceptive behavioural responses in the awake pig following UV-B-induced inflammation. Eur J Pain 2013; 18:20-8. [PMID: 23720380 DOI: 10.1002/j.1532-2149.2013.00340.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2013] [Indexed: 01/15/2023]
Abstract
BACKGROUND Among the current translational inflammatory pain models, the ultraviolet (UV) irradiation is of rapidly growing interest. The development of primary thermal and mechanical hyperalgesia has been observed in humans and rodents. The pig as a translational animal model might be advantageous due to its great homology with humans. METHODS The skin in the flank of awake pigs was irradiated by a UV-B light source (1 J/cm(2) ) and changes in thermal and mechanical sensitivity 24 and 48 h following irradiation were measured via assessment of nociceptive behaviours. RESULTS Thermal sensitivity increased significantly within the inflamed site 24 h after irradiation as indicated by the reduction of latency to respond to thermal stimulation from baseline to 24 h (P < 0.05). At 48 h, the response latency had not decreased any further (P = 0.414). Thermal sensitivity was also higher at the inflamed skin site than at the control site 24 and 48 h following irradiation (P < 0.05). An overall decrease of 50% of the baseline mechanical threshold was observed 24 and 48 h following UV-B irradiation (P = 0.092). Following the inflammatory challenge, the mechanical sensitivity was higher at the site of irradiation compared with the control skin at both 24 and 48 h (P < 0.05). CONCLUSIONS Our study shows that behavioural recordings are a valid tool for the assessment of thermal hyperalgesia following UV-B inflammation in porcine skin, but they were not capable of providing a clear indication of the development of mechanical hyperalgesia.
Collapse
Affiliation(s)
- P Di Giminiani
- Department of Animal Science, Aarhus University, Tjele, Denmark
| | | | | |
Collapse
|
15
|
The pattern and time course of somatosensory changes in the human UVB sunburn model reveal the presence of peripheral and central sensitization. Pain 2013; 154:586-597. [DOI: 10.1016/j.pain.2012.12.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 11/14/2012] [Accepted: 12/20/2012] [Indexed: 12/21/2022]
|
16
|
Granmo M, Jensen T, Schouenborg J. Nociceptive transmission to rat primary somatosensory cortex--comparison of sedative and analgesic effects. PLoS One 2013; 8:e53966. [PMID: 23320109 PMCID: PMC3540052 DOI: 10.1371/journal.pone.0053966] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 12/06/2012] [Indexed: 11/18/2022] Open
Abstract
CO(2)-laser C-fibre evoked cortical potentials (LCEPs) is a potentially useful animal model for studies of pain mechanisms. A potential confounding factor when assessing analgesic effects of systemically administered drugs using LCEP is sedation. This study aims to clarify: 1) the relation between level of anaesthesia and magnitude of LCEP, 2) the effects of a sedative and an analgesic on LCEP and dominant EEG frequency 3) the effects of a sedative and analgesic on LCEP when dominant EEG frequency is kept stable. LCEP and EEG were recorded in isoflurane/nitrous-oxide anaesthetized rats. Increasing isoflurane level gradually reduced LCEPs and lowered dominant EEG frequencies. Systemic midazolam (10 μmol/kg) profoundly reduced LCEP (19% of control) and lowered dominant EEG frequency. Similarly, morphine 1 and 3 mg/kg reduced LCEP (39%, 12% of control, respectively) and decreased EEG frequency. When keeping the dominant EEG frequency stable, midazolam caused no significant change of LCEP. Under these premises, morphine at 3 mg/kg, but not 1 mg/kg, caused a significant LCEP reduction (26% of control). In conclusion, the present data indicate that the sedative effects should be accounted for when assessing the analgesic effects of drug. Furthermore, it is suggested that LCEP, given that changes in EEG induced by sedation are compensated for, can provide information about the analgesic properties of systemically administrated drugs.
Collapse
Affiliation(s)
- Marcus Granmo
- Neuronano Research Center, Department of Experimental Medical Sciences, Lund University, Lund, Sweden.
| | | | | |
Collapse
|
17
|
Ultraviolet B-induced inflammation in the rat: A model of secondary hyperalgesia? Pain 2011; 152:2844-2851. [DOI: 10.1016/j.pain.2011.09.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 08/08/2011] [Accepted: 09/16/2011] [Indexed: 01/31/2023]
|
18
|
Safieh-Garabedian B, Jabbur SJ, Dardenne M, Saadé NE. Thymulin related peptide attenuates inflammation in the brain induced by intracerebroventricular endotoxin injection. Neuropharmacology 2011; 60:496-504. [DOI: 10.1016/j.neuropharm.2010.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 09/28/2010] [Accepted: 11/02/2010] [Indexed: 12/18/2022]
|
19
|
Jensen T, Granmo M, Schouenborg J. Altered nociceptive C fibre input to primary somatosensory cortex in an animal model of hyperalgesia. Eur J Pain 2010; 15:368-75. [PMID: 20947398 DOI: 10.1016/j.ejpain.2010.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 09/15/2010] [Accepted: 09/20/2010] [Indexed: 10/19/2022]
Abstract
Evaluating potentially analgesic effects of drugs and various treatments is critically dependent on valid animal models of pain. Since primary somatosensory (SI) cortex is likely to play an important role in processing sensory aspects of pain, we here assess whether monitoring SI cortex nociceptive C fibre evoked potentials can provide useful information about central changes related to hyperalgesia in rats. Recordings of tactile and CO(2)-laser C fibre evoked potentials (LCEPs) in forelimb and hind limb SI cortex were made 20-24h after UV-B irradiation of the heel at a dose that produced behavioural signs of hyperalgesia. LCEPs from irradiated skin increased significantly in duration but showed no significant change in magnitude, measured as area under curve (AUC). By contrast, LCEPs in hind limb SI cortex from skin sites nearby the irradiated skin showed no increase in duration or onset latency but increased significantly in magnitude after UV-B irradiation. The LCEPs in forelimb or hind limb SI cortex elicited from forelimb skin did not change in magnitude, but were significantly delayed in hind limb SI cortex. Tramadol, a centrally acting analgesic known to reduce hyperalgesia, induced changes that counteracted the changes produced by UV-B irradiation on transmission to SI cortex from the hind paw, but had no significant effect on time course of LCEPs from forelimb skin. Tactile evoked potentials were not affected by UV-B irradiation or tramadol. We conclude that altered sensory processing related to hyperalgesia is reflected in altered LCEPs in SI cortex.
Collapse
Affiliation(s)
- Tanja Jensen
- Neuronano Research Center, Section for Neuroscience, Lund University, BMC F10, SE-221 84 Lund, Sweden.
| | | | | |
Collapse
|
20
|
Chen HS, Qu F, He X, Wang Y, Wen WW. Chemical or surgical sympathectomy prevents mechanical hyperalgesia induced by intraplantar injection of bee venom in rats. Brain Res 2010; 1353:86-93. [DOI: 10.1016/j.brainres.2010.07.069] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 07/18/2010] [Accepted: 07/19/2010] [Indexed: 11/15/2022]
|
21
|
Drummond PD. Inflammatory consequences of cutaneous stimulation. Exp Neurol 2010; 222:181-3. [DOI: 10.1016/j.expneurol.2010.01.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 01/19/2010] [Accepted: 01/21/2010] [Indexed: 01/11/2023]
|
22
|
Rukwied R, Mayer A, Kluschina O, Obreja O, Schley M, Schmelz M. NGF induces non-inflammatory localized and lasting mechanical and thermal hypersensitivity in human skin. Pain 2009; 148:407-413. [PMID: 20022698 DOI: 10.1016/j.pain.2009.11.022] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 11/03/2009] [Accepted: 11/25/2009] [Indexed: 10/20/2022]
Abstract
Nerve growth factor (NGF) modulates sensitivity and sprouting of nociceptors. We explored the spatial and temporal sensitization induced by NGF injection (1 microg) in human skin. Hyperalgesia was investigated in 16 volunteers (36+/-9 years) at day 1, 3, 7, 21, and 49. Areas of mechanical (brush, pin-prick) and heat (43 degrees C) sensitization were mapped and thermal (heat and cold) pain thresholds, mechanical (impact stimulation) and electrically evoked pain, and axon reflex flare were assessed. No spontaneous pain or local inflammation was recorded upon NGF injection and during 49 days. Sensitization to heat was maximum at day 3 and lasted 21 days. Hyperalgesia to cold was recorded at day 7 and 21. Hypersensitivity to mechanical impact stimuli developed delayed, reached maximum at day 21, and persisted throughout 49 days. Fifty percent of all volunteers reported a static allodynia to tonic pressure until day 21. Electrical stimulation at 7.5 mA was more painful at the NGF site at day 21, which correlated significantly to maximum impact pain. Axon reflex flare was unaffected by NGF. Sensitization was limited to the NGF injection site, no touch- or pin-prick evoked secondary hyperalgesia was observed. Spatially restricted hyperalgesia indicates a peripheral rather than central mechanism. The temporal profile of lasting nociceptor sensitization suggests an altered peripheral axonal expression of sensory proteins specifically leading to mechanical and thermal sensitization. Intradermal NGF administration provokes a pattern of sensitization that can be used as experimental model for neuropathic pain.
Collapse
Affiliation(s)
- Roman Rukwied
- Department of Anaesthesiology and Intensive Care Medicine Mannheim, Heidelberg University, Germany
| | | | | | | | | | | |
Collapse
|
23
|
Histamine potentiates acid-induced responses mediating transient receptor potential V1 in mouse primary sensory neurons. Neuroscience 2009; 166:292-304. [PMID: 20006972 DOI: 10.1016/j.neuroscience.2009.12.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 11/27/2009] [Accepted: 12/01/2009] [Indexed: 01/06/2023]
Abstract
In inflamed tissues, extracellular pH decreases and acidosis is an important source of pain. Histamine is released from mast cells under inflammatory conditions and evokes the pain sensation in vivo, but the cellular mechanism of histamine-induced pain has not been well understood. In the present study, we examined the effects of histamine on [Ca(2+)](i) and membrane potential responses to acid in isolated mouse dorsal root ganglion (DRG) neurons. In capsaicin-sensitive DRG neurons from wild-type mice, acid (>pH 5.0) evoked [Ca(2+)](i) increases, but not in DRG neurons from transient receptor potential V1 (TRPV1) (-/-) mice. Regardless of isolectin GS-IB4 (IB4)-staining, histamine potentiated [Ca(2+)](i) responses to acid (>or=pH 6.0) that were mediated by TRPV1 activation. Histamine increased membrane depolarization induced by acid and evoked spike discharges. RT-PCR indicated the expression of all four histamine receptors (H1R, H2R, H3R, H4R) in mouse DRG. The potentiating effect of histamine was mimicked by an H1R agonist, but not H2R-H4R agonists and was inhibited only by an H1R antagonist. Histamine failed to potentiate the [Ca(2+)](i) response to acid in the presence of inhibitors for phospholipase C (PLC) and protein kinase C (PKC). A lipoxygenase inhibitor and protein kinase A inhibitor did not affect the potentiating effects of histamine. Carrageenan and complete Freund's adjuvant produced inflammatory hyperalgesia, but these inflammatory conditions did not change the potentiating effects of histamine in DRG neurons. The present results suggest that histamine sensitizes acid-induced responses through TRPV1 activation via H1R coupled with PLC/PKC pathways, the action of which may be involved in the generation of inflammatory pain.
Collapse
|
24
|
Chizh BA, Priestley T, Rowbotham M, Schaffler K. Predicting therapeutic efficacy — Experimental pain in human subjects. ACTA ACUST UNITED AC 2009; 60:243-54. [DOI: 10.1016/j.brainresrev.2008.12.016] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2008] [Indexed: 02/05/2023]
|
25
|
Transient increase in cytokines and nerve growth factor in the rat dorsal root ganglia after nerve lesion and peripheral inflammation. J Neuroimmunol 2009; 208:94-103. [DOI: 10.1016/j.jneuroim.2009.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 12/17/2008] [Accepted: 01/09/2009] [Indexed: 01/17/2023]
|
26
|
Chizh BA, Greenspan JD, Casey KL, Nemenov MI, Treede RD. Identifying biological markers of activity in human nociceptive pathways to facilitate analgesic drug development. Pain 2008; 140:249-253. [PMID: 18950938 PMCID: PMC4711771 DOI: 10.1016/j.pain.2008.09.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 09/02/2008] [Accepted: 09/19/2008] [Indexed: 11/20/2022]
Affiliation(s)
- Boris A. Chizh
- GlaxoSmithKline, Addenbrooke’s Centre for Clinical Investigation, Cambridge CB2 2GG, UK
| | - Joel D. Greenspan
- Department of Neural and Pain Sciences, Dental School and Program in Neuroscience, University of Maryland, Baltimore, MD 21201, USA
| | - Kenneth L. Casey
- University of Michigan and VA Medical Center, Ann Arbor, MI 48109, USA
| | - Michael I. Nemenov
- Pain Research Center, Anesthesia Department, Stanford University, Stanford, CA 94305 and LASMED LLC, Mountain View, CA 94043, USA
| | - Rolf-Detlef Treede
- Department of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim (CBTM), University of Heidelberg, D-68167 Mannheim, Germany
| |
Collapse
|