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Zhu X, Xie W, Zhang J, Strong JA, Zhang JM. Sympathectomy decreases pain behaviors and nerve regeneration by downregulating monocyte chemokine CCL2 in dorsal root ganglia in the rat tibial nerve crush model. Pain 2022; 163:e106-e120. [PMID: 33941753 PMCID: PMC8556407 DOI: 10.1097/j.pain.0000000000002321] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 04/15/2021] [Indexed: 01/03/2023]
Abstract
ABSTRACT Peripheral nerve regeneration is associated with pain in several preclinical models of neuropathic pain. Some neuropathic pain conditions and preclinical neuropathic pain behaviors are improved by sympathetic blockade. In this study, we examined the effect of a localized "microsympathectomy," ie, cutting the gray rami containing sympathetic postganglionic axons where they enter the L4 and L5 spinal nerves, which is more analogous to clinically used sympathetic blockade compared with chemical or surgical sympathectomy. We also examined manipulations of CCL2 (monocyte chemoattractant protein 1), a key player in both regeneration and pain. We used rat tibial nerve crush as a neuropathic pain model in which peripheral nerve regeneration can occur successfully. CCL2 in the sensory ganglia was increased by tibial nerve crush and reduced by microsympathectomy. Microsympathectomy and localized siRNA-mediated knockdown of CCL2 in the lumbar dorsal root ganglion had very similar effects: partial improvement of mechanical hypersensitivity and guarding behavior, reduction of regeneration markers growth-associated protein 43 and activating transcription factor 3, and reduction of macrophage density in the sensory ganglia and regenerating nerve. Microsympathectomy reduced functional regeneration as measured by myelinated action potential propagation through the injury site and denervation-induced atrophy of the tibial-innervated gastrocnemius muscle at day 10. Microsympathectomy plus CCL2 knockdown had behavioral effects similar to microsympathectomy alone. The results show that local sympathetic effects on neuropathic pain may be mediated in a large part by the effects on expression of CCL2, which in turn regulates the regeneration process.
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Affiliation(s)
- Xiaoyan Zhu
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, U.S.A
- Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Wenrui Xie
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, U.S.A
| | - Jingdong Zhang
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, U.S.A
| | - Judith A. Strong
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, U.S.A
| | - Jun-Ming Zhang
- Pain Research Center, Department of Anesthesiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, U.S.A
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Dorsal Root Ganglion Stimulation Alleviates Pain-related Behaviors in Rats with Nerve Injury and Osteoarthritis. Anesthesiology 2020; 133:408-425. [PMID: 32433276 DOI: 10.1097/aln.0000000000003348] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Dorsal root ganglion field stimulation is an analgesic neuromodulation approach in use clinically, but its mechanism is unknown as there is no validated animal model for this purpose. The authors hypothesized that ganglion stimulation is effective in reducing pain-like behaviors in preclinical chronic pain models. METHODS The authors provided ganglion stimulation or spinal cord stimulation to rats with traumatic neuropathy (tibial nerve injury), or osteoarthritis induced by intraarticular knee monosodium iodoacetate, or without injury (naïve). Analgesia was evaluated by testing a battery of pain-related reflexive, functional, and affective behaviors. RESULTS In rats with nerve injury, multilevel L4 and L5 ganglion stimulation decreased hypersensitivity to noxious mechanical stimulation more (area under curve, -1,447 ± 423 min × % response; n = 12) than single level ganglion stimulation at L4 ([-960 ± 251 min × % response; n = 8; P = 0.012] vs. L4 and L5), and L5 ([-676 ± 295 min × % response; n = 8; P < 0.0001] vs. L4 and L5). Spontaneous pain-like behavior, evaluated by conditioned place preference, responded to single L4 (Pretest [-93 ± 65 s] vs. Test [87 ± 82 s]; P = 0.002; n = 9), L5 (Pretest [-57 ± 36 s] vs. Test [137 ± 73 s]; P = 0.001; n = 8), and multilevel L4 and L5 (Pretest: -81 ± 68 s vs. Test: 90 ± 76 s; P = 0.003; n = 8) ganglion stimulation. In rats with osteoarthritis, multilevel L3 and L4 ganglion stimulation reduced sensitivity to knee motion more (-156 ± 28 min × points; n = 8) than L3 ([-94 ± 19 min × points in knee bend test; n = 7; P = 0.002] vs. L3 and L4) or L4 ([-71 ± 22 min × points; n = 7; P < 0.0001] vs. L3 and L4). Conditioned place preference during osteoarthritis revealed analgesic effectiveness for ganglion stimulation when delivered at L3 (Pretest [-78 ± 77 s] vs. Test [68 ± 136 s]; P = 0.048; n = 9), L4 (Pretest [-96 ± 51 s] vs. Test [73 ± 111 s]; P = 0.004; n = 9), and L3 and L4 (Pretest [-69 ± 52 s; n = 7] vs. Test [55 ± 140 s]; P = 0.022; n = 7). CONCLUSIONS Dorsal root ganglion stimulation is effective in neuropathic and osteoarthritic preclinical rat pain models with peripheral pathologic origins, demonstrating effectiveness of ganglion stimulation in a placebo-free setting and justifying this model as a suitable platform for mechanistic studies.
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Xie W, Strong JA, Zhang JM. Localized sympathectomy reduces peripheral nerve regeneration and pain behaviors in 2 rat neuropathic pain models. Pain 2020; 161:1925-1936. [PMID: 32701850 PMCID: PMC7572566 DOI: 10.1097/j.pain.0000000000001887] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Previous studies have shown that the peripheral nerve regeneration process is linked to pain in several neuropathic pain models. Other studies show that sympathetic blockade may relieve pain in some pain models and clinical conditions. This study examined reduction in peripheral nerve regeneration as one possible mechanism for relief of neuropathic pain by sympathetic blockade. A "microsympathectomy," consisting of cutting the gray rami containing sympathetic postganglionic axons where they enter the L4 and L5 spinal nerves, reduced mechanical hypersensitivity in 2 different rat neuropathic pain models. In the spinal nerve ligation model, in which some functional regeneration and reinnervation of the ligated spinal nerve can be observed, microsympathectomy reduced functional and anatomical measures of regeneration as well as expression of growth-associated protein 43 (GAP43), a regeneration-related protein. In the spared nerve injury model, in which functional reinnervation is not possible and the futile regeneration process results in formation of a neuroma, microsympathectomy reduced neuroma formation and GAP43 expression. In both models, microsympathectomy reduced macrophage density in the sensory ganglia and peripheral nerve. This corroborates previous work showing that sympathetic nerves may locally affect immune function. The results further highlight the challenge of improving pain in neuropathic conditions without inhibiting peripheral nerve regeneration that might otherwise be possible and desired.
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Affiliation(s)
- Wenrui Xie
- Department of Anesthesiology, Pain Research Center, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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Kosaka Y, Yafuso T, Shimizu-Okabe C, Kim J, Kobayashi S, Okura N, Ando H, Okabe A, Takayama C. Development and persistence of neuropathic pain through microglial activation and KCC2 decreasing after mouse tibial nerve injury. Brain Res 2020; 1733:146718. [PMID: 32045595 DOI: 10.1016/j.brainres.2020.146718] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 01/27/2020] [Accepted: 02/07/2020] [Indexed: 12/20/2022]
Abstract
Gamma-amino butyric acid (GABA) is an inhibitory neurotransmitter in the mature brain, but is excitatory during development and after motor nerve injury. This difference in GABAergic action depends on the intracellular chloride ion concentration ([Cl-]i), primarily regulated by potassium chloride co-transporter 2 (KCC2). To reveal precise processes of the neuropathic pain through changes in GABAergic action, we prepared tibial nerve ligation and severance models using male mice, and examined temporal relationships amongst changes in (1) the mechanical withdrawal threshold in the sural nerve area, (2) localization of the molecules involved in GABAergic transmission and its upstream signaling in the dorsal horn, and (3) histology of the tibial nerve. In the ligation model, tibial nerve degeneration disappeared by day 56, but mechanical allodynia, reduced KCC2 localization, and increased microglia density remained until day 90. Microglia density was higher in the tibial zone than the sural zone before day 21, but this result was inverted after day 28. In contrast, in the severance model, all above changes were detected until day 28, but were simultaneously and significantly recovered by day 90. These results suggested that in male mice, allodynia may be caused by reduced GABAergic synaptic inhibition, resulting from elevated [Cl-]i after the reduction of KCC2 by activated microglia. Furthermore, our results suggested that factors from degenerating nerve terminals may diffuse into the sural zone, whereby they induced the development of allodynia in the sural nerve area, while other factors in the sural zone may mediate persistent allodynia through the same pathway.
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Affiliation(s)
- Yoshinori Kosaka
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara 207, Nishihara, Okinawa 9030215, Japan
| | - Tsukasa Yafuso
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara 207, Nishihara, Okinawa 9030215, Japan
| | - Chigusa Shimizu-Okabe
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara 207, Nishihara, Okinawa 9030215, Japan
| | - Jeongtae Kim
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara 207, Nishihara, Okinawa 9030215, Japan; Department of Veterinary Anatomy, College of Veterinary Medicine, Jeju National University, Jeju 63243, Republic of Korea
| | - Shiori Kobayashi
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara 207, Nishihara, Okinawa 9030215, Japan
| | - Nobuhiko Okura
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara 207, Nishihara, Okinawa 9030215, Japan
| | - Hironobu Ando
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara 207, Nishihara, Okinawa 9030215, Japan
| | - Akihito Okabe
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara 207, Nishihara, Okinawa 9030215, Japan; Department of Nutritional Science, Faculty of Health and Welfare, Seinan Jo Gakuin University, Fukuoka 803-0835, Japan
| | - Chitoshi Takayama
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara 207, Nishihara, Okinawa 9030215, Japan.
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Kaya C, Atalay YO, Meydan BC, Ustun YB, Koksal E, Caliskan S. [Evaluation of the neurotoxic effects of intrathecal administration of (S)-(+)-Ketoprofen on rat spinal cords: randomized controlled experimental study]. BRAZILIAN JOURNAL OF ANESTHESIOLOGY (ELSEVIER) 2019; 69:403-412. [PMID: 31371174 PMCID: PMC9391909 DOI: 10.1016/j.bjan.2019.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 03/08/2019] [Accepted: 03/17/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND AND OBJECTIVES Intrathecal administration of non-steroidal anti-inflammatory drugs is more efficacious for post-operative pain management. Cyclooxygenase inhibiting non-steroidal anti-inflammatory drugs like (S)-(+)-Ketoprofen, may be effective at lower intrathecal doses than parenteral ones. Preclinical safety regarding possible neurotoxicity associated with the intrathecal (S)-(+)-Ketoprofen was not evaluated. Here we analysed the neurotoxicity of intrathecally administered (S)-(+)-Ketoprofen in rats. METHODS A randomized placebo-controlled experimental study was conducted. Sprague-Dawley rats (250-300g) aged 12-16 weeks were randomly divided into 2 treatments [100 and 800μg (S)-(+)-Ketoprofen] and control (sterile water) groups. Intrathecal catheters were placed via the atlantoaxial space in anesthetized rats. Pinch-toe tests, motor function evaluations and histopathological examinations of the spinal cord and nerve roots were performed at days 3, 7 and 21. Spinal cord sections were evaluated by light microscopy for the dorsal axonal funiculus vacuolation, axonal myelin loss, neuronal chromatolysis, neuritis, meningeal inflammation, adhesions, and fibrosis. RESULTS Rats in all the groups exhibited normal pinch-toe testing response (score=0) and normal gait at each observed time (motor function evaluation score=1). Neurotoxicity was higher with treatments on days 3 and 7 than that on day 21 (2, 3, 0, p=0.044; 2, 5, 0, p=0.029, respectively). On day 7, the total scores reflecting neuronal damage were higher in the 800μg group than those in the 100μg and Control Groups (5, 3, 0, p=0.048, respectively). CONCLUSION Intrathecal (S)-(+)-Ketoprofen caused dose-dependent neurohistopathological changes in rats on days 3 and 7 after injection, suggesting that (S)-(+)-Ketoprofen should not be intrathecally administered.
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Affiliation(s)
- Cengiz Kaya
- Ondokuz Mayis University, School of Medicine, Department of Anesthesiology, Kurupelit, Turquia.
| | - Yunus O Atalay
- Ondokuz Mayis University, School of Medicine, Department of Radiology, Kurupelit, Turquia
| | - Bilge C Meydan
- Ondokuz Mayis University, School of Medicine, Department of Pathology, Kurupelit, Turquia
| | - Yasemin B Ustun
- Ondokuz Mayis University, School of Medicine, Department of Anesthesiology, Kurupelit, Turquia
| | - Ersin Koksal
- Ondokuz Mayis University, School of Medicine, Department of Anesthesiology, Kurupelit, Turquia
| | - Sultan Caliskan
- Ondokuz Mayis University, School of Medicine, Department of Pathology, Kurupelit, Turquia
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Kaya C, Atalay YO, Meydan BC, Ustun YB, Koksal E, Caliskan S. Evaluation of the neurotoxic effects of intrathecal administration of (S)-(+)-Ketoprofen on rat spinal cords: randomized controlled experimental study. BRAZILIAN JOURNAL OF ANESTHESIOLOGY (ENGLISH EDITION) 2019. [PMID: 31371174 PMCID: PMC9391909 DOI: 10.1016/j.bjane.2019.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Background and objectives Intrathecal administration of non-steroidal anti-inflammatory drugs is more efficacious for post-operative pain management. Cyclooxygenase inhibiting non-steroidal anti-inflammatory drugs like (S)-(+)-Ketoprofen, may be effective at lower intrathecal doses than parenteral ones. Preclinical safety regarding possible neurotoxicity associated with the intrathecal (S)-(+)-Ketoprofen was not evaluated. Here we analysed the neurotoxicity of intrathecally administered (S)-(+)-Ketoprofen in rats. Methods A randomized placebo-controlled experimental study was conducted. Sprague-Dawley rats (250–300 g) aged 12–16 weeks were randomly divided into 2 treatments [100 and 800 μg (S)-(+)-Ketoprofen] and control (sterile water) groups. Intrathecal catheters were placed via the atlantoaxial space in anesthetized rats. Pinch-toe tests, motor function evaluations and histopathological examinations of the spinal cord and nerve roots were performed at days 3, 7 and 21. Spinal cord sections were evaluated by light microscopy for the dorsal axonal funiculus vacuolation, axonal myelin loss, neuronal chromatolysis, neuritis, meningeal inflammation, adhesions, and fibrosis. Results Rats in all the groups exhibited normal pinch-toe testing response (score = 0) and normal gait at each observed time (motor function evaluation score = 1). Neurotoxicity was higher with treatments on days 3 and 7 than that on day 21 (2, 3, 0, p = 0.044; 2, 5, 0, p = 0.029, respectively). On day 7, the total scores reflecting neuronal damage were higher in the 800 μg group than those in the 100 μg and Control Groups (5, 3, 0, p = 0.048, respectively). Conclusion Intrathecal (S)-(+)-Ketoprofen caused dose-dependent neurohistopathological changes in rats on days 3 and 7 after injection, suggesting that (S)-(+)-Ketoprofen should not be intrathecally administered.
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Activation of liver x receptors prevents the spinal LTP induced by skin/muscle retraction in the thigh via SIRT1/NF-Κb pathway. Neurochem Int 2019; 128:106-114. [PMID: 31018150 DOI: 10.1016/j.neuint.2019.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/03/2019] [Accepted: 04/05/2019] [Indexed: 01/31/2023]
Abstract
It has been reported that skin/muscle incision and retraction (SMIR) in the thigh, produces mechanical allodynia in the hind paw, far from the site of incision/retraction. The mechanical allodynia lasts about 22 days, indicating chronic post-operative pain develops. The precise mechanisms, however, are largely unclear. In the current study, we further found that SMIR surgery induced LTP of c-fiber evoked field potentials that lasted at least 4 h. The mRNA and protein level of tumor necrosis factor-alpha (TNFα) and acetylated nuclear factor-kappaB p65 (ac-NF-κB p65) in the lumbar spinal dorsal horn was gradually increased during LTP development, while pretreatment with either TNFα neutralization antibody or NF-κB inhibitor PDTC completely prevented the induction of LTP. Moreover, the expression of Silent information regulator 1 (SIRT1) in the lumbar spinal dorsal horn was decreased and activation of SIRT1 by SRT1720 also prevented the induction of LTP. Importantly, the spinal expression of Liver X receptors (LXRs) was increased, both at mRNA and protein level following SMIR. Application of LXRs agonist T0901317 to the spinal dorsal horn prevented LTP induction following SMIR. Mechanistically, T0901317 enhanced the expression of SIRT1 and decreased the expression of ac-NF-κB p65 and TNFα. Spinal application of SIRT1 antagonist EX-527, 30 min before T0901317 administration, completely blocked the inhibiting effect of T0901317 on LTP, and on expression of ac-NF-κB p65 and TNFα. These results indicated that activation of LXRs prevented SMIR-induced LTP by inhibiting NF-κB/TNFα pathway via increasing SIRT1 expression.
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Civi S, Durdag E, Aytar MH, Kardes O, Kaymaz F, Aykol S. Usefulness of End-to-Side Bridging Anastomosis of Sural Nerve to Tibial Nerve: An Experimental Research. J Korean Neurosurg Soc 2017; 60:417-423. [PMID: 28689390 PMCID: PMC5544376 DOI: 10.3340/jkns.2016.1010.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/17/2016] [Accepted: 02/13/2017] [Indexed: 01/28/2023] Open
Abstract
Objective Repair of sensorial nerve defect is an important issue on peripheric nerve surgery. The aim of the present study was to determine the effects of sensory-motor nerve bridging on the denervated dermatomal area, in rats with sensory nerve defects, using a neural cell adhesion molecule (NCAM). Methods We compared the efficacy of end-to-side (ETS) coaptation of the tibial nerve for sural nerve defect repair, in 32 Sprague-Dawley rats. Rats were assigned to 1 of 4 groups: group A was the sham operated group, group B rats had sural nerves sectioned and buried in neighboring muscles, group C experienced nerve sectioning and end-to-end (ETE) anastomosis, and group D had sural nerves sectioned and ETS anastomosis was performed using atibial nerve bridge. Neurological evaluation included the skin pinch test and histological evaluation was performed by assessing NCAM expression in nerve terminals. Results Rats in the denervated group yielded negative results for the skin pinch tests, while animals in the surgical intervention groups (group C and D) demonstrated positive results. As predicted, there were no positively stained skin specimens in the denervated group (group B); however, the surgery groups demonstrated significant staining. NCAM expression was also significantly higher in the surgery groups. However, the mean NCAM values were not significantly different between group C and group D. Conclusion Previous research indicates that ETE nerve repair is the gold standard for peripheral nerve defect repair. However, ETS repair is an effective alternative method in cases of sensorial nerve defect when ETE repair is not possible.
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Affiliation(s)
- Soner Civi
- Department of Neurosurgery, Başkent University Faculty of Medicine, Adana, Turkey
| | - Emre Durdag
- Department of Neurosurgery, Başkent University Faculty of Medicine, Adana, Turkey
| | - Murat Hamit Aytar
- Department of Neurosurgery, Acibadem University Vocational School of Health Services, İstanbul, Turkey
| | - Ozgur Kardes
- Department of Neurosurgery, Başkent University Faculty of Medicine, Adana, Turkey
| | - Figen Kaymaz
- Department of Histology and Embryology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Sukru Aykol
- Department of Neurosurgery, Gazi University Faculty of Medicine, Ankara, Turkey
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Active Nerve Regeneration with Failed Target Reinnervation Drives Persistent Neuropathic Pain. eNeuro 2017; 4:eN-NWR-0008-17. [PMID: 28197545 PMCID: PMC5290455 DOI: 10.1523/eneuro.0008-17.2017] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 12/29/2022] Open
Abstract
Peripheral nerves can regenerate and, when injured, may cause neuropathic pain. We propose that the active regeneration process plays a pivotal role in the maintenance of neuropathic pain. In one commonly used rodent neuropathic pain model, pronounced pain behaviors follow ligation and cutting of the L5 spinal nerve. We found that the injured nerve regenerates into the sciatic nerve and functionally reinnervates target tissues: the regenerated nerve conducts electrical signals, mechanical responses, and tracers between the leg/hindpaw and axotomized sensory ganglion. The regenerating nerve is the primary source of abnormal spontaneous activity detected in vivo. Disrupting the regeneration inhibited pain. First, semaphorin 3A, an inhibitory axonal guidance molecule, reduced functional regeneration, spontaneous activity, and pain behaviors when applied to the injury site in vivo. Second, knockdown of the upregulated growth-associated protein 43 (GAP43) with siRNA injected into the axotomized sensory ganglion reduced pain behaviors. We next examined the spared nerve injury model, in which pain behaviors are essentially permanent. The regeneration resulted in tangled GAP43-positive neuromas at the nerve injury site without target reinnervation. Perfusing the nerve stump with semaphorin 3A, but not removing the tangled fibers, prevented or reversed pain behaviors. This effect far outlasted the semaphorin 3A perfusion. Hence, in this model the long-lasting chronic pain may reflect the anatomical inability of regenerating nerves to successfully reinnervate target tissues, resulting in an ongoing futile regeneration process. We propose that specifically targeting the regeneration process may provide effective long-lasting pain relief in patients when functional reinnervation becomes impossible.
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Sun Y, Yang M, Tang H, Ma Z, Liang Y, Li Z. The over-production of TNF-α via Toll-like receptor 4 in spinal dorsal horn contributes to the chronic postsurgical pain in rat. J Anesth 2015; 29:734-40. [PMID: 25895164 DOI: 10.1007/s00540-015-2011-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 03/29/2015] [Indexed: 11/29/2022]
Abstract
PURPOSE Many patients suffer from chronic postsurgical pain (CPSP) following surgery, and the underlying mechanisms are poorly understood. In the present work, using the skin/muscle incision retraction (SMIR) model, the role of spinal TLR4/TNF-α pathway in the induction of CPSP was evaluated. METHODS Mechanical allodynia induced by SMIR was established in adult male Sprague-Dawley rats. The von Frey test was performed to evaluate the role of TLR4/TNF-α pathway on the mechanical allodynia. Western-blot and immunohistochemistry methods were adopted to understand the molecular mechanisms. RESULTS SMIR surgery decreased the ipsilateral 50 % paw withdrawal threshold, lasting for at least 20 days. Western-blot analysis and immunohistochemistry revealed that SMIR surgery significantly upregulated the expression of TLR4 (p < 0.01) in glial cells on the ipsilateral side of spinal cord and increased TLR4 occurred on day 5 and was maintained to the end of the experiment (day 20). Similarly, tumor necrosis factor-alpha (TNF-α) was significantly increased on days 5, 10, and 20 on the ipsilateral side of spinal dorsal horn following SMIR surgery. Intraperitoneal injection of an inhibitor of TNF-α synthesis thalidomide at 50 or 100 mg/kg dose (but not 10 mg/kg dose) significantly ameliorated the reduced paw withdrawal threshold induced by SMIR surgery. Importantly, intrathecal delivery of a specific TLR4 antagonist (LPS-RS) at dose of 25 μg significantly attenuated mechanical allodynia and prevented the upregulation of TNF-α induced by SMIR surgery. CONCLUSIONS These findings suggest that the upregulation of TNF-α via TLR4 contributes to the development of CPSP in spinal dorsal horn.
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Affiliation(s)
- Yang Sun
- Department of Pain, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan South Road, Urumqi, Xinjiang, 830054, China
| | - Mingmin Yang
- Department of Pain, The First Affiliated Hospital of Xinjiang Medical University, 137 Liyushan South Road, Urumqi, Xinjiang, 830054, China
| | - Hao Tang
- Department of General Internal Medicine, The First Affiliated Hospital of Sun Yat-sen University, Sun Yet-Sen University, 58 Zhongshan Rd. 2, Guangzhou, 510080, China
| | - Zhongfu Ma
- Department of General Internal Medicine, The First Affiliated Hospital of Sun Yat-sen University, Sun Yet-Sen University, 58 Zhongshan Rd. 2, Guangzhou, 510080, China
| | - Yanbing Liang
- Department of General Internal Medicine, The First Affiliated Hospital of Sun Yat-sen University, Sun Yet-Sen University, 58 Zhongshan Rd. 2, Guangzhou, 510080, China
| | - Zhenyu Li
- Department of General Internal Medicine, The First Affiliated Hospital of Sun Yat-sen University, Sun Yet-Sen University, 58 Zhongshan Rd. 2, Guangzhou, 510080, China.
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Savastano LE, Laurito SR, Fitt MR, Rasmussen JA, Gonzalez Polo V, Patterson SI. Sciatic nerve injury: A simple and subtle model for investigating many aspects of nervous system damage and recovery. J Neurosci Methods 2014; 227:166-80. [DOI: 10.1016/j.jneumeth.2014.01.020] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 01/16/2014] [Accepted: 01/20/2014] [Indexed: 02/04/2023]
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Petruska JC, Barker DF, Garraway SM, Trainer R, Fransen JW, Seidman PA, Soto RG, Mendell LM, Johnson RD. Organization of sensory input to the nociceptive-specific cutaneous trunk muscle reflex in rat, an effective experimental system for examining nociception and plasticity. J Comp Neurol 2014; 522:1048-71. [PMID: 23983104 PMCID: PMC3945951 DOI: 10.1002/cne.23461] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 07/18/2013] [Accepted: 08/14/2013] [Indexed: 12/21/2022]
Abstract
Detailed characterization of neural circuitries furthers our understanding of how nervous systems perform specific functions and allows the use of those systems to test hypotheses. We have characterized the sensory input to the cutaneous trunk muscle (CTM; also cutaneus trunci [rat] or cutaneus maximus [mouse]) reflex (CTMR), which manifests as a puckering of the dorsal thoracolumbar skin and is selectively driven by noxious stimuli. CTM electromyography and neurogram recordings in naïve rats revealed that CTMR responses were elicited by natural stimuli and electrical stimulation of all segments from C4 to L6, a much greater extent of segmental drive to the CTMR than previously described. Stimulation of some subcutaneous paraspinal tissue can also elicit this reflex. Using a selective neurotoxin, we also demonstrate differential drive of the CTMR by trkA-expressing and nonexpressing small-diameter afferents. These observations highlight aspects of the organization of the CTMR system that make it attractive for studies of nociception and anesthesiology and plasticity of primary afferents, motoneurons, and the propriospinal system. We use the CTMR system to demonstrate qualitatively and quantitatively that experimental pharmacological treatments can be compared with controls applied either to the contralateral side or to another segment, with the remaining segments providing controls for systemic or other treatment effects. These data indicate the potential for using the CTMR system as both an invasive and a noninvasive quantitative assessment tool providing improved statistical power and reduced animal use.
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Affiliation(s)
- Jeffrey C. Petruska
- University of Louisville, Department of Anatomical Sciences and Neurobiology, 500 S. Preston St., Louisville, KY 40202
- University of Louisville, Kentucky Spinal Cord Injury Research Center, Department of Neurological Surgery
| | - Darrell F. Barker
- SUNY Stony Brook, Dept. Neurobiology and Behavior, 550 Life Sciences Building, Stony Brook, NY 11794-5230
| | - Sandra M. Garraway
- Emory University School of Medicine, Department of Physiology, 615 Michael Street, Atlanta, GA 30322-3110,
| | - Robert Trainer
- SUNY Stony Brook, Department of Anesthesiology, School of Medicine, Stony Brook, NY 11794-8081
| | - James W. Fransen
- University of Louisville, Department of Anatomical Sciences and Neurobiology, 500 S. Preston St., Louisville, KY 40202
| | - Peggy A. Seidman
- SUNY Stony Brook, Department of Anesthesiology, School of Medicine, Stony Brook, NY 11794-8081
| | - Roy G. Soto
- SUNY Stony Brook, Department of Anesthesiology, School of Medicine, Stony Brook, NY 11794-8081
| | - Lorne M. Mendell
- SUNY Stony Brook, Dept. Neurobiology and Behavior, 550 Life Sciences Building, Stony Brook, NY 11794-5230
| | - Richard D. Johnson
- University of Florida, Dept. Physiological Sciences, JHMHC Box 100144, Gainesville, FL 32210-0144
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Ogbonna AC, Clark AK, Gentry C, Hobbs C, Malcangio M. Pain-like behaviour and spinal changes in the monosodium iodoacetate model of osteoarthritis in C57Bl/6 mice. Eur J Pain 2012; 17:514-26. [PMID: 23169679 DOI: 10.1002/j.1532-2149.2012.00223.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2012] [Indexed: 01/25/2023]
Abstract
BACKGROUND Osteoarthritis (OA) is a highly prevalent, age-related pain condition that poses a significant clinical problem. Here, in the monosodium iodoacetate (MIA) model of OA, we have characterized pain behaviours and associated changes at the first pain synapse in the dorsal horn of the spinal cord. METHODS Mice received intra-articular injections of 0.5, 0.75 and 1 mg MIA and mechanical paw withdrawal threshold was monitored for up to 4 weeks. An intrathecal injection of peptide antagonist calcitonin gene-related peptide (CGRP8-37 ) was given 3 weeks post MIA and paw withdrawal thresholds were measured after 1 and 3 h. Immunohistochemical analysis of the lumbar dorsal horn was carried out and activity-evoked CGRP release was measured from isolated lumbar dorsal horn slices - with dorsal roots attached. RESULTS By 2 weeks after intra-articular MIA injection, mechanical hypersensitivity was established in the ipsilateral hindpaw. There was no evidence of sensory neuron damage in lumbar dorsal root ganglia 7 days after 1 mg MIA. However, both dorsal horn neuron activation and microglial response (Fos and Iba-1 immunostaining) but not reactive astrocytes (glial fibrillary acidic protein) were observed. Evoked CGRP release was greater from dorsal horn slices of MIA-treated mice compared with control. Furthermore, intrathecal administration of peptide antagonist CGRP8-37 acutely attenuated established MIA-induced mechanical hypersensitivity. CONCLUSIONS Intra-articular MIA is associated with referred mechanical hypersensitivity and increased release of CGRP from primary afferent fibres in the dorsal horn where second-order neuron activation is associated with a microglial response. Antagonism of CGRP receptor activation provides a therapeutic avenue for the treatment of pain in OA.
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Affiliation(s)
- A C Ogbonna
- Wolfson Centre for Age-Related Diseases, King's College London, UK
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Lim SM, Shin MR, Kang KH, Kang H, Nahm FS, Kim BH, Shin HY, Lim YJ, Lee SC. Evaluation of the Neurological Safety of Epidural Milnacipran in Rats. Korean J Pain 2012; 25:228-37. [PMID: 23091683 PMCID: PMC3468799 DOI: 10.3344/kjp.2012.25.4.228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 07/23/2012] [Accepted: 08/03/2012] [Indexed: 11/24/2022] Open
Abstract
Background Milnacipran is a balanced serotonin norepinephrine reuptake inhibitor with minimal side effects and broad safety margin. It acts primarily on the descending inhibitory pain pathway in brain and spinal cord. In many animal studies, intrathecal administration of milnacipran is effective in neuropathic pain management. However, there is no study for the neurological safety of milnacipran when it is administered neuraxially. This study examined the neurotoxicity of epidural milnacipran by observing behavioral and sensory-motor changes with histopathological examinations of spinal cords in rats. Methods Sixty rats were divided into 3 groups, with each group receiving epidural administration of either 0.3 ml (3 mg) of milnacipran (group M, n = 20), 0.3 ml of 40% alcohol (group A, n = 20), or 0.3 ml of normal saline (group S, n = 20). Results There were no abnormal changes in the behavioral, sensory-motor, or histopathological findings in all rats of groups M and S over a 3-week observation period, whereas all rats in group A had abnormal changes. Conclusions Based on these findings, the direct epidural administration of milnacipran in rats did not present any evidence of neurotoxicity in behavioral, sensory-motor and histopathological evaluations.
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Affiliation(s)
- Seung Mo Lim
- Department of Anesthesiology and Pain Medicine, Chung-Ang University College of Medicine, Seoul, Korea
| | - Mee Ran Shin
- Department of Prosthodontics, Dentistry, Hangang Sacred Heart Hospital, Graduated School of Clinical Dentistry, Hallym University, Seoul, Korea
| | - Kyung Ho Kang
- Department of Surgery, Chung-Ang University College of Medicine, Seoul, Korea
| | - Hyun Kang
- Department of Anesthesiology and Pain Medicine, Chung-Ang University College of Medicine, Seoul, Korea
| | - Francis Sahngun Nahm
- Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Baek Hui Kim
- Department of Pathology, Korea University College of Medicine, Seoul, Korea
| | - Hwa Yong Shin
- Department of Prosthodontics, Dentistry, Hangang Sacred Heart Hospital, Graduated School of Clinical Dentistry, Hallym University, Seoul, Korea
| | - Young Jin Lim
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Korea
| | - Sang Chul Lee
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Korea
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15
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Lee JR, Lee PB, Choe G, Lee SC, Lee HM, Kim E, Kim YC. Evaluation of the neurological safety of epidurally-administered pregabalin in rats. Korean J Anesthesiol 2012; 62:57-65. [PMID: 22323956 PMCID: PMC3272531 DOI: 10.4097/kjae.2012.62.1.57] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 06/27/2011] [Accepted: 07/11/2011] [Indexed: 11/28/2022] Open
Abstract
Background The primary site of action of pregabalin, i.e. the α-2-δ subunit of the voltage-dependent calcium channel, is located at the dorsal root ganglion and dorsal horn of the spinal cord. Therefore, the epidural administration of pregabalin could have advantages over oral administration. However, the possibility of its neurotoxicity should be excluded before any attempt at epidural administration. We evaluated the neuronal safety of epidurally-administered pregabalin by observing the sensory/motor changes and examining the histopathology of spinal cord in rats. Methods Sixty rats of 180-230 g were divided into three groups; 3 mg of pregabalin dissolved in 0.3 ml saline (group P, n = 20), 0.3 ml 40% alcohol (group A, n = 20), or 0.3 ml normal saline (group N, n = 20) was administered epidurally to the rats in each group. Pinch-toe test, motor function evaluation, and histopathologic examination of vacuolation, chromatolysis, meningeal inflammation, and neuritis were performed at the 1st, 3rd, 7th, and 21st day after each epidural administration. Results All rats enrolled in group P, like those in group N, showed neither sensory/motor dysfunction nor any histopathological abnormality over the 3-week observation period. In contrast, in group A, 80% of the rats showed abnormal response to the pinch-toe test and all rats showed decreased motor function during the entire evaluation period. In addition, all histopathologic findings of neurotoxicity were observed exclusively in group A. Conclusions The epidurally administered pregabalin (about 15 mg/kg) did not cause any neurotoxic evidence, in terms of both sensory/motor function evaluation and histopathological examination in rats.
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Affiliation(s)
- Jeong Rim Lee
- Department of Anesthesiology and Pain Medicine, Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea
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Lin YT, Ro LS, Wang HL, Chen JC. Up-regulation of dorsal root ganglia BDNF and trkB receptor in inflammatory pain: an in vivo and in vitro study. J Neuroinflammation 2011; 8:126. [PMID: 21958434 PMCID: PMC3203068 DOI: 10.1186/1742-2094-8-126] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 09/30/2011] [Indexed: 11/16/2022] Open
Abstract
Background During inflammation, immune cells accumulate in damaged areas and release pro-inflammatory cytokines and neurotrophins. Brain-derived neurotrophic factor (BDNF) plays a neuromodulatory role in spinal cord dorsal horn via the post-synaptic tyrosine protein kinase B (trkB) receptor to facilitate pain transmission. However, the precise role of BDNF and trkB receptor in the primary sensory neurons of dorsal root ganglia (DRG) during inflammation remains to be clarified. The aim of this study was to investigate whether and how BDNF-trkB signaling in the DRG is involved in the process of inflammatory pain. Methods We used complete Freund's adjuvant- (CFA-) induced and tumor necrosis factor-α- (TNF-α-) induced inflammation in rat hindpaw as animal models of inflammatory pain. Quantification of protein and/or mRNA levels of pain mediators was performed in separate lumbar L3-L5 DRGs. The cellular mechanism of TNF-α-induced BDNF and/or trkB receptor expression was examined in primary DRG cultures collected from pooled L1-L6 DRGs. Calcitonin gene-related peptide (CGRP), BDNF and substance P release were also evaluated by enzyme immunoassay. Results CFA injection into rat hindpaw resulted in mechanical hyperalgesia and significant increases in levels of TNF-α in the inflamed tissues, along with enhancement of BDNF and trkB receptor as well as the pain mediators CGRP and transient receptor potential vanilloid receptor subtype 1 (TRPV1) in DRG. Direct injection of TNF-α into rat hindpaw resulted in similar effects with retrograde transport of TNF-α along the saphenous nerve to DRG during CFA-induced inflammation. Primary DRG cultures chronically treated with TNF-α showed significant enhancement of mRNA and protein levels of BDNF and trkB receptor, BDNF release and trkB-induced phospho-ERK1/2 signal. Moreover, CGRP and substance P release were enhanced in DRG cultures after chronic TNF-α treatment or acute BDNF stimulation. In addition, we found that BDNF up-regulated trkB expression in DRG cultures. Conclusions Based on our current experimental results, we conclude that inflammation and TNF-α up-regulate the BDNF-trkB system in DRG. This phenomenon suggests that up-regulation of BDNF in DRG may, in addition to its post-synaptic effect in spinal dorsal horn, act as an autocrine and/or paracrine signal to activate the pre-synaptic trkB receptor and regulate synaptic excitability in pain transmission, thereby contributing to the development of hyperalgesia.
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Affiliation(s)
- Ya-Tin Lin
- Department of Physiology and Pharmacology, Chang-Gung University, Taiwan, Republic of China
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Reid AJ, Mantovani C, Shawcross SG, Terenghi G, Wiberg M. Phenotype of distinct primary sensory afferent subpopulations and caspase-3 expression following axotomy. Histochem Cell Biol 2011; 136:71-8. [PMID: 21674244 DOI: 10.1007/s00418-011-0829-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2011] [Indexed: 12/20/2022]
Abstract
Specific sensory neuronal subpopulations show contrasting responses to peripheral nerve injury, as shown by the axotomy-induced death of many cutaneous sensory neurons whilst muscular sensory afferents survive an identical insult. We used a novel combination of retrograde neuronal tracing with immunohistochemistry and laser microdissection techniques, in order to describe the neurochemistry of medial gastrocnemius (muscular sensory afferents) and sural (cutaneous sensory afferents) branches of the rat sciatic nerve and relate this to the pro-apoptotic caspase-3 gene expression following nerve transection. Our results demonstrated distinctions in medial gastrocnemius and sural neuron populations with the most striking difference in the respective proportions of isolectin B4 (IB4) staining neurons (3.7 V 32.8%). The mean neuronal area of the medial gastrocnemius (MG) neurons was larger than that of the sural (SUR) neurons (1,070.8 V 646.2 μm²) and each phenotypic group was significantly smaller in sural neurons than in MG neurons. At 1 week post-axotomy, MG neurons markedly downregulated caspase-3, whilst SUR neurons upregulated caspase-3 gene expression; this may be attributable to the differing IB4-positive composition of the subpopulations. These findings provide further clarification in the understanding of two distinct neuronal populations used increasingly in nerve injury models.
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Affiliation(s)
- Adam J Reid
- Blond McIndoe Research Laboratories, Tissue Injury and Repair Group, University of Manchester, Oxford Road, Manchester, UK.
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18
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Kim YH, Lee PB, Park J, Lim YJ, Kim YC, Lee SC, Ahn W. The neurological safety of epidural parecoxib in rats. Neurotoxicology 2011; 32:864-70. [PMID: 21669221 DOI: 10.1016/j.neuro.2011.05.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 05/20/2011] [Accepted: 05/23/2011] [Indexed: 12/13/2022]
Abstract
Epidural injection of cyclooxygenase-2 inhibitors has been suggested as a useful therapeutic modality in pain management in animal studies and clinical settings. Direct epidural administration of parecoxib, a highly selective cyclooxygenase-2 inhibitor, may have advantages over its parenteral administration regarding required dose, side effects, and efficacy. However, no animal studies have been performed to investigate the possible neurotoxicity of epidurally injected parecoxib. Therefore, the present study was performed to assess the neurotoxicity of epidurally injected parecoxib in rats. Rats (n=45) were randomly divided into three groups: normal saline group (group N, n=15), ethanol group (group E, n=15), and parecoxib group (group P, n=15). 0.3 mL of epidural parecoxib (6 mg) and the same volume of epidural ethanol or normal saline were injected into the epidural space. Neurologic assessment was performed 3, 7 and 21 days after the injection by pinch toe testing. Histologic changes were evaluated for vacuolation of the dorsal funiculus, chromatolytic changes of the motor neurons, neuritis, and meningeal inflammation. All rats in groups N and P showed normal response to pinch-toe testing and had a normal gait at each observation point. Histological examination showed no evidence suggestive of neuronal body or axonal lesions, gliosis, or myelin sheet damage in group N or P at any time. However, all rats in group E showed sensory-motor dysfunction, behavioral change, or histopathological abnormalities. No neurotoxicity on the spinal cord or abnormalities in sensorimotor function or behavior was noted in rats that received epidural parecoxib.
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Affiliation(s)
- Yang Hyun Kim
- Department of Anesthesiology, National Cancer Center, Goyangsi, Republic of Korea
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Moalem-Taylor G, Li M, Allbutt HN, Wu A, Tracey DJ. A preconditioning nerve lesion inhibits mechanical pain hypersensitivity following subsequent neuropathic injury. Mol Pain 2011; 7:1. [PMID: 21205324 PMCID: PMC3022745 DOI: 10.1186/1744-8069-7-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 01/05/2011] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND A preconditioning stimulus can trigger a neuroprotective phenotype in the nervous system - a preconditioning nerve lesion causes a significant increase in axonal regeneration, and cerebral preconditioning protects against subsequent ischemia. We hypothesized that a preconditioning nerve lesion induces gene/protein modifications, neuronal changes, and immune activation that may affect pain sensation following subsequent nerve injury. We examined whether a preconditioning lesion affects neuropathic pain and neuroinflammation after peripheral nerve injury. RESULTS We found that a preconditioning crush injury to a terminal branch of the sciatic nerve seven days before partial ligation of the sciatic nerve (PSNL; a model of neuropathic pain) induced a significant attenuation of pain hypersensitivity, particularly mechanical allodynia. A preconditioning lesion of the tibial nerve induced a long-term significant increase in paw-withdrawal threshold to mechanical stimuli and paw-withdrawal latency to thermal stimuli, after PSNL. A preconditioning lesion of the common peroneal induced a smaller but significant short-term increase in paw-withdrawal threshold to mechanical stimuli, after PSNL. There was no difference between preconditioned and unconditioned animals in neuronal damage and macrophage and T-cell infiltration into the dorsal root ganglia (DRGs) or in astrocyte and microglia activation in the spinal dorsal and ventral horns. CONCLUSIONS These results suggest that prior exposure to a mild nerve lesion protects against adverse effects of subsequent neuropathic injury, and that this conditioning-induced inhibition of pain hypersensitivity is not dependent on neuroinflammation in DRGs and spinal cord. Identifying the underlying mechanisms may have important implications for the understanding of neuropathic pain due to nerve injury.
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Affiliation(s)
- Gila Moalem-Taylor
- School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
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20
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Unal-Cevik I, Oaklander AL. Comparing Partial and Total Tibial-Nerve Axotomy: Long-Term Effects on Prevalence and Location of Evoked Pain Behaviors. Pain Pract 2010; 11:109-19. [DOI: 10.1111/j.1533-2500.2010.00429.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lee PB, Kim YC, Lee CJ, Shin HY, Lee SY, Park JC, Choi YS, Kim CS, Park SH. The neurological safety of epidural pamidronate in rats. Korean J Pain 2010; 23:116-23. [PMID: 20556213 PMCID: PMC2886240 DOI: 10.3344/kjp.2010.23.2.116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 03/19/2010] [Accepted: 03/30/2010] [Indexed: 11/05/2022] Open
Abstract
Background Pamidronate is a potent inhibitor of osteoclast-mediated bone resorption. Recently, the drug has been known to relieve bone pain. We hypothesized that direct epidural administration of pamidronate could have various advantages over oral administration with respect to dosage, side effects, and efficacy. Therefore, we evaluated the neuronal safety of epidurally-administered pamidronate. Methods Twenty-seven rats weighing 250-350 g were equally divided into 3 groups. Each group received an epidural administration with either 0.3 ml (3.75 mg) of pamidronate (group P), 0.3 ml of 40% alcohol (group A), or 0.3 ml of normal saline (group N). A Pinch-toe test, motor function evaluation, and histopathologic examination of the spinal cord to detect conditions such as chromatolysis, meningeal inflammation, and neuritis, were performed on the 2nd, 7th, and 21st day following administration of each drug. Results All rats in group A showed an abnormal response to the pinch-toe test and decreased motor function during the entire evaluation period. Abnormal histopathologic findings, including neuritis and meningeal inflammation were observed only in group A rats. Rats in group P, with the exception of 1, and group N showed no significant sensory/motor dysfunction over a 3-week observation period. No histopathologic changes were observed in groups P and N. Conclusions Direct epidural injection of pamidronate (about 12.5 mg/kg) showed no neurotoxic evidence in terms of sensory/motor function evaluation and histopathologic examination.
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Affiliation(s)
- Pyung Bok Lee
- Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Korea
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Reid AJ, Welin D, Wiberg M, Terenghi G, Novikov LN. Peripherin and ATF3 genes are differentially regulated in regenerating and non-regenerating primary sensory neurons. Brain Res 2009; 1310:1-7. [PMID: 19913522 DOI: 10.1016/j.brainres.2009.11.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 10/24/2009] [Accepted: 11/05/2009] [Indexed: 01/10/2023]
Abstract
Peripheral nerve injury leads to deficient recovery of sensation and a causative factor may be that only 50-60% of primary sensory neurons succeed in regenerating axons after primary nerve repair. In this study, an in vivo rat sciatic nerve injury and regeneration model was combined with laser microdissection and quantitative real-time polymerase chain reaction with the aim of examining the gene expression of regenerative molecules in cutaneous and muscular sensory neurons. Recent studies have identified peripherin and ATF-3 molecules as crucial for neurite outgrowth propagation; our novel findings demonstrate a subpopulation of non-regenerating sensory neurons characterized by a failure to upregulate transcription of these molecules and that a greater peripherin mRNA expression in injured cutaneous neurons may potentiate this subpopulation to regenerate more axons than muscle afferent neurons following injury. The gene expression of the structural neurofilament NF-H is found to be significantly downregulated following injury in both sensory subpopulations.
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Affiliation(s)
- Adam J Reid
- Blond McIndoe Research Laboratories, Tissue Injury and Repair Group, University of Manchester, UK.
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Bahraminasab A, Ghasemi F, Stefanovska A, McClintock PVE, Friedrich R. Physics of brain dynamics: Fokker-Planck analysis reveals changes in EEG delta and theta activity during anaesthesia. NEW JOURNAL OF PHYSICS 2009; 11:103051. [PMID: 20823955 PMCID: PMC2933827 DOI: 10.1088/1367-2630/11/10/103051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We use drift and diffusion coefficients to reveal interactions between different oscillatory processes underlying a complex signal and apply the method to EEG delta and theta frequencies in the brain. By analysis of data recorded from rats during anaesthesia we consider the stability and basins of attraction of fixed points in the phase portrait of the deterministic part of the retrieved stochastic process. We show that different classes of dynamics are associated with deep and light anaesthesia, and we demonstrate that the predominant directionality of the interaction is such that theta drives delta.
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Affiliation(s)
- A. Bahraminasab
- Department of Physics, Lancaster University, Lancaster LA1 4YB, UK, ; ;
| | - F. Ghasemi
- Institute of Theoretical Physics, Westfälische Wilhelms-Universität Wilhelm-Klemm-Str. 9, 48149 Münster, Germany, ;
| | - A. Stefanovska
- Department of Physics, Lancaster University, Lancaster LA1 4YB, UK, ; ;
| | | | - R. Friedrich
- Institute of Theoretical Physics, Westfälische Wilhelms-Universität Wilhelm-Klemm-Str. 9, 48149 Münster, Germany, ;
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Murphy DR, Hurwitz EL, Gerrard JK, Clary R. Pain patterns and descriptions in patients with radicular pain: does the pain necessarily follow a specific dermatome? CHIROPRACTIC & OSTEOPATHY 2009; 17:9. [PMID: 19772560 PMCID: PMC2753622 DOI: 10.1186/1746-1340-17-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/02/2009] [Accepted: 09/21/2009] [Indexed: 02/07/2023]
Abstract
Background It is commonly stated that nerve root pain should be expected to follow a specific dermatome and that this information is useful to make the diagnosis of radiculopathy. There is little evidence in the literature that confirms or denies this statement. The purpose of this study is to describe and discuss the diagnostic utility of the distribution of pain in patients with cervical and lumbar radicular pain. Methods Pain drawings and descriptions were assessed in consecutive patients diagnosed with cervical or lumbar nerve root pain. These findings were compared with accepted dermatome maps to determine whether they tended to follow along the involved nerve root's dermatome. Results Two hundred twenty-six nerve roots in 169 patients were assessed. Overall, pain related to cervical nerve roots was non-dermatomal in over two-thirds (69.7%) of cases. In the lumbar spine, the pain was non-dermatomal in just under two-thirds (64.1%) of cases. The majority of nerve root levels involved non-dermatomal pain patterns except C4 (60.0% dermatomal) and S1 (64.9% dermatomal). The sensitivity (SE) and specificity (SP) for dermatomal pattern of pain are low for all nerve root levels with the exception of the C4 level (Se 0.60, Sp 0.72) and S1 level (Se 0.65, Sp 0.80), although in the case of the C4 level, the number of subjects was small (n = 5). Conclusion In most cases nerve root pain should not be expected to follow along a specific dermatome, and a dermatomal distribution of pain is not a useful historical factor in the diagnosis of radicular pain. The possible exception to this is the S1 nerve root, in which the pain does commonly follow the S1 dermatome.
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Harvey VL, Dickenson AH. Behavioural and electrophysiological characterisation of experimentally induced osteoarthritis and neuropathy in C57Bl/6 mice. Mol Pain 2009; 5:18. [PMID: 19379487 PMCID: PMC2678995 DOI: 10.1186/1744-8069-5-18] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 04/20/2009] [Indexed: 11/30/2022] Open
Abstract
Background Osteoarthritis is a widespread condition affecting the elderly where ~70–90% of over 75 year olds are affected, representing one of the largest cost burdens to healthcare in the western world. The monosodium iodoacetate (MIA) osteoarthritis model has been well described in the rat especially in terms of the pathological progression of the disease and more recently pain behaviour. In this study, we characterise, for the first time, MIA induced osteoarthritis in mice and compare it with nerve-injured mice (partial sciatic nerve injury), using both behavioural and in vivo electrophysiological measurements. These approaches uniquely allow the threshold and suprathreshold measures to many modalities to be quantified and so form a basis for improving and expanding transgenic studies. Results Significant mechanical hypersensitivity was observed in the ipsilateral hindpaw in MIA injected mice at all observed time points following infrapetellar MIA injection (p < 0.05). The mechanical hypersensitivity exhibited a partial biphasic temporal pattern, but thermal hypersensitivity was absent. Electrically-evoked dorsal horn neuronal responses in MIA injected mice were significantly elevated (p < 0.05) with respect to A- and C-fibre firing, input, pinch and noxious von Frey (26 and 60 g). No significant changes in A- or C-fibre thresholds were observed. Nerve-injured mice displayed significant behavioural thermal and mechanical hypersensitivity (p < 0.05) and evoked dorsal horn responses were significantly increased with respect to C-fibre firing, pinch and wind-up (p < 0.05). Conclusion The MIA model of osteoarthritic pain in mice displays behavioural characteristics similar to those observed in rats. Changes in both behavioural measures and neuronal activity from the paw, suggest that central changes are involved in this pain state, although a role for peripheral drives is also likely. Moreover, the behavioural and neuronal measures in these two pain models showed overlapping alterations in terms of certain neuronal measures and mechanical sensitivity despite their very different pathologies and a loss of input in neuropathy, suggesting some commonalities in the central processing of different peripheral pain states. This murine model of osteoarthritis will allow the exploitation of knock out animals to better understand underlying mechanisms and identify novel molecular targets.
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Affiliation(s)
- Victoria L Harvey
- Neuroscience, Physiology and Pharmacology, University College London, Gower St, London WC1E 6BT, UK.
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Lee JW, Siegel SM, Oaklander AL. Effects of distal nerve injuries on dorsal-horn neurons and glia: relationships between lesion size and mechanical hyperalgesia. Neuroscience 2008; 158:904-14. [PMID: 18992304 DOI: 10.1016/j.neuroscience.2008.10.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2008] [Revised: 09/29/2008] [Accepted: 10/27/2008] [Indexed: 10/21/2022]
Abstract
Penetrating limb injuries are common and usually heal without long-lasting effects, even when nerves are cut. However, rare nerve-injury patients develop prolonged and disabling chronic pain (neuralgia). When pain severity is disproportionate to severity of the inciting injury, physicians and insurers may suspect exaggeration and limit care or benefits, although the nature of the relationship between lesion-size and the development and persistence of neuralgia remains largely unknown. We compared cellular changes in the spinal dorsal-horn (the initial CNS pain-processing area) after partial or total tibial-nerve axotomies in male Sprague-Dawley rats to determine if these changes are proportional to the numbers of peripheral axons cut. Unoperated rats provided controls. Plantar hind-paw responses to touch, pin, and cold were quantitated bilaterally to identify hyperalgesic rats. We also compared data from nerve-injured rats with or without hyperalgesic responses to mechanical hind-paw stimulation to evaluate concordance between pain behaviors and dorsal-horn cellular changes. Hyperalgesia was no less prevalent or severe after partial than after total axotomy. L(5) spinal-cord sections from rats killed 7 days postoperatively were labeled for markers of primary afferents (substance P calcitonin gene-related peptide isolectin B4, gamma aminobutyric acid, and glial fibrillary acidic protein), then labeled cells were stereologically quantitated in somatotopically defined dorsal-horn regions. Total axotomy reduced markers of primary afferents more than partial axotomy. In contrast, GABA-immunoreactive profiles were similarly reduced after both lesions, and in rats with sensory loss versus hyperalgesia. Numbers of GFAP-immunoreactive astrocytes increased independently of lesion size and pain status. Small nerve injuries can thus have magnified and disproportionate effects on dorsal-horn neurons and glia, perhaps providing a biological correlate for the disproportionate pain of post-traumatic neuralgias (including complex regional pain syndrome-I) that follow seemingly minor nerve injuries. However, the presence of similar dorsal-horn changes in rats without pain behaviors suggests that not all transcellular responses to axotomy are pain-specific.
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Affiliation(s)
- J W Lee
- Departments of Neurology and Pathology, Massachusetts General Hospital, Harvard Medical School, 275 Charles Street, Warren 310, Boston, MA 02114, USA
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Kovacic U, Sketelj J, Bajrović FF. Sex-related differences in recovery of cutaneous nociception after end-to-side nerve repair in the rat. J Plast Reconstr Aesthet Surg 2008; 62:806-13. [PMID: 18417437 DOI: 10.1016/j.bjps.2007.09.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 07/27/2007] [Accepted: 09/05/2007] [Indexed: 02/06/2023]
Abstract
Sex-related differences in the recovery of cutaneous nociception after end-to-side nerve repair were examined in rats. Recovery of nociception in the dorsal foot was determined by skin pinch test 19 weeks after the proximal end of the distal stump of the transected peroneal nerve was sutured to the side of the adjacent intact sural nerve (end-to-side nerve coaptation). Axon sprouts in the recipient peroneal nerve were counted by light and electron microscopy. Recovery of nociception due to axon sprouting through the end-to-side coaptation was found in 87% of females and in 60% of males. The area of nociception was not significantly different (P=0.59) between females and males (13+/-8% and 11+/-9%, respectively). The number of myelinated axons in the recipient peroneal nerve (but not of unmyelinated axons) was significantly larger (P=0.028) in females (median=512, 25th and 75th percentiles: 467 and 594) than in males (median=322, 25th and 75th percentiles: 239 and 468). The majority of these axons in females and males were thin fibres, and recipient nerves in both groups were responsive to nerve pinch test. In conclusion, collateral sprouting of thin myelinated nociceptive axons into the end-to-side coapted nerve is more abundant in female than in male rats. However, recovery of cutaneous mechano-nociception due to sprouting of these axons was not different between the two sexes. Possible reasons are discussed.
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Affiliation(s)
- Uros Kovacic
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana, Slovenia.
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Siegel SM, Lee JW, Oaklander AL. Needlestick Distal Nerve Injury in Rats Models Symptoms of Complex Regional Pain Syndrome. Anesth Analg 2007; 105:1820-9, table of contents. [DOI: 10.1213/01.ane.0000295234.21892.bc] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Flatters SJL. Characterization of a model of persistent postoperative pain evoked by skin/muscle incision and retraction (SMIR). Pain 2007; 135:119-30. [PMID: 17590272 PMCID: PMC2278124 DOI: 10.1016/j.pain.2007.05.013] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Revised: 05/07/2007] [Accepted: 05/15/2007] [Indexed: 10/23/2022]
Abstract
Various surgical procedures, e.g. thoracotomy and inguinal hernia repair, frequently evoke persistent pain lasting for many months following the initial surgery. The essential prolonged tissue retraction required during such surgeries may account for the persistence and high incidence of postoperative pain in these patient populations. This study describes a new rat model of persistent postoperative pain evoked by skin/muscle incision and retraction (SMIR), akin to a clinical procedure. Under anaesthesia, skin and superficial muscle of the medial thigh were incised and a small pair of retractors inserted. This tissue was retracted for 1h causing potential stretch of the saphenous nerve. SMIR surgery evoked persistent significant mechanical hypersensitivity to von Frey stimulation of the plantar ipsilateral hindpaw, compared to either pre-surgery responses or concurrent responses of sham-operated rats. SMIR-evoked mechanical hypersensitivity was observed by postoperative day 3, most prominent between postoperative days 10 and 13, persisted until at least postoperative day 22 and had dissipated by postoperative day 32. Overall, mechanical sensitivity of the SMIR contralateral paw and the sham ipsilateral paw did not significantly change from pre-surgery responses. SMIR did not evoke significant heat hyperalgesia or cold allodynia. Light microscopy of saphenous nerve sections did not show degeneration or oedema in the saphenous nerve at, or proximally or distally to, the surgical site. In addition, very little to no degeneration was detected with ATF3 staining in DRG from SMIR-operated rats. These data suggest that prolonged retraction of superficial tissue evokes a persistent pain syndrome that is not driven by neuronal damage.
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Affiliation(s)
- Sarah J L Flatters
- Pain Research Center - MRB611, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham & Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA.
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Kovacic U, Tomsic M, Sketelj J, Bajrović FF. Collateral sprouting of sensory axons after end-to-side nerve coaptation—A longitudinal study in the rat. Exp Neurol 2007; 203:358-69. [PMID: 17045263 DOI: 10.1016/j.expneurol.2006.08.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Revised: 07/26/2006] [Accepted: 08/18/2006] [Indexed: 12/19/2022]
Abstract
The end-to-side nerve coaptation is able to induce collateral sprouting of axons from the donor nerve and to provide functional reinnervation of the target tissue. Sensory axon sprouting and its effects on the donor nerve up to 9 months after the end-to-side nerve coaptation were studied in the rat. Peroneal, tibial and saphenous nerves were transected and ligated, and the distal stump of the transected peroneal nerve was sutured to the side of the uninjured sural nerve. The average skin area of the residual sensitivity to pinch due to the axons sprouting through the recipient peroneal nerve did not change statistically significantly between 4 and 9 months after surgery. Axon counting, measurements of compound action potentials and retrograde neuron labeling indicate that the sprouting of the myelinated sensory axons and unmyelinated axons through the recipient nerve was largely completed by 2 months and 4 months after the end-to-side nerve coaptation, respectively, and remained stable thereafter for at least 9 months. A decrease in the amplitude and area of the CAP of myelinated fibers, observed in the donor nerve up to 4 months after surgery, was probably due to mild degeneration of nerve fibers and a tendency of the diameter of myelinated axons to decline. However, no significant changes in functional, electrophysiological or morphological properties of the donor nerve could be observed at the end of the observational period, indicating that end-to-side nerve coaptation has no detrimental effect on the donor nerve on a long-term scale.
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Affiliation(s)
- Uros Kovacic
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloska 4, 1000 Ljubljana, Slovenia
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Musizza B, Stefanovska A, McClintock PVE, Palus M, Petrovcic J, Ribaric S, Bajrovic FF. Interactions between cardiac, respiratory and EEG-delta oscillations in rats during anaesthesia. J Physiol 2007; 580:315-26. [PMID: 17234691 PMCID: PMC2075429 DOI: 10.1113/jphysiol.2006.126748] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We hypothesized that, associated with the state of anaesthesia, characteristic changes exist in both cardio-respiratory and cerebral oscillator parameters and couplings, perhaps varying with depth of anaesthesia. Electrocardiograms (ECGs), respiration and electroencephalograms (EEGs) were recorded from two groups of 10 rats during the entire course of anaesthesia following the administration of a single bolus of ketamine-xylazine (KX group) or pentobarbital (PB group). The phase dynamics approach was then used to extract the instantaneous frequencies of heart beat, respiration and slow delta-waves (within 0.5-3.5 Hz). The amplitudes of delta- and theta-waves were analysed by use of a time-frequency representation of the EEG signal within 0.5-7.5 Hz obtained by wavelet transformation, using the Morlet mother wavelet. For the KX group, where slow delta-waves constituted the dominant spectral component, the Hilbert transform was applied to obtain the instantaneous delta-frequency. The theta-activity was spread over too wide a spectral range for its phase to be meaningfully defined. For both agents, we observed two distinct phases of anaesthesia, with a marked increase in theta-wave activity occurring on passage from a deeper phase of anaesthesia to a shallower one. In other respects, the effects of the two anaesthetics were very different. For KX anaesthesia, the two phases were separated by a marked change in all three instantaneous frequencies: stable, deep, anaesthesia with small frequency variability was followed by a sharp transition to shallow anaesthesia with large frequency variability, lasting until the animal awoke. The transition occurred 16-76 min after injection of the anaesthetic, with simultaneous reduction in the delta-wave amplitude. For PB anaesthesia, the two epochs were separated by the return of a positive response to the pinch test at 53-94 min, following which it took a further period of 45-70 min for the animal to awaken. delta-Waves were not apparent at any stage of PB anaesthesia. We applied non-linear dynamics and information theory to seek evidence of causal relationships between the cardiac, respiratory and slow delta-oscillations. We demonstrate that, for both groups, respiration drives the cardiac oscillator during deep anaesthesia. During shallow KX anaesthesia the direction either reverses, or the cardio-respiratory interaction becomes insignificant; in the deep phase, there is a unidirectional deterministic interaction of respiration with slow delta-oscillations. For PB anaesthesia, the cardio-respiratory interaction weakens during the second phase but, otherwise, there is no observable change in the interactions. We conclude that non-linear dynamics and information theory can be used to identify different stages of anaesthesia and the effects of different anaesthetics.
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Affiliation(s)
- Bojan Musizza
- Department of Systems and Control, Jozef Stefan Institute, Jamova 39, Ljubljana, Slovenia
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Choi SS, Kim YC, Lim YJ, Lee CJ, Lee PB, Lee SC, Sim WS, Choi YL. The Neurological Safety of Epidural Gabapentin in Rats: A Light Microscopic Examination. Anesth Analg 2005; 101:1422-1426. [PMID: 16244005 DOI: 10.1213/01.ane.0000180197.32577.9b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Gabapentin acts primarily on the central nervous system. Therefore, we hypothesized that the direct epidural administration of gabapentin could have various advantages over its oral administration with respect to required dose, side effects, and efficacy. However, before administering gabapentin into the epidural space in a clinical setting, its neurotoxicity must be examined in animals. Thus, we evaluated neurotoxicity of epidural gabapentin by observing behavioral and sensory-motor changes, and by histopathological examinations of spinal cords and dorsal root ganglia in the rat. Twenty-seven rats were randomly divided into 3 groups, which were administered 0.3 mL (30 mg) of epidural gabapentin (group G, n = 9) and the same volume of epidural alcohol (group A, n = 9) or normal saline (group N, n = 9). No rats in groups G and N showed sensory-motor dysfunction, behavioral change, or histopathological abnormalities over a 3-wk observation period, whereas all rats in group A showed abnormalities. We conclude that the direct epidural injection of gabapentin in rats did not show any neurotoxic evidence in terms of sensory-motor functions and behavior, or by a microscopic histopathological evaluation. This study represents a first promising step toward the trial of epidural gabapentin in a clinical setting.
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Affiliation(s)
- Sang-Sik Choi
- *Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine; and Departments of †Anesthesiology and Pain Medicine and ‡Diagnostic Pathology, SungKyunKwan University College of Medicine, Seoul, Korea
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Kovacic U, Sketelj J, Bajrović FF. Sex-related difference in collateral sprouting of nociceptive axons after peripheral nerve injury in the rat. Exp Neurol 2004; 184:479-88. [PMID: 14637117 DOI: 10.1016/s0014-4886(03)00269-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Possible sex-related differences in the extent of collateral sprouting of noninjured nociceptive axons after peripheral nerve injury were examined. In the first experiment, peroneal, tibial, and saphenous nerves were transected and ligated in female and male rats. Eight weeks after nerve injury, skin pinch tests revealed that the nociceptive area of the noninjured sural nerve in the instep skin expanded faster in females; the final result was a 30% larger increase in females than in males. In the second experiment, the end-to-side nerve anastomosis was used as a model for axon sprouting. In addition to the previous procedure, the end of an excised peroneal nerve segment was sutured to the side of the intact sural nerve. Eight weeks later, collateral sprouting of nociceptive axons into the anastomosed peroneal nerve segment was assessed by the nerve pinch test and axon counting. There was no significant difference with respect to the percentages of male and female rats with a positive nerve pinch test. The number of myelinated axons in the anastomosed nerve segment was significantly larger in female (456 +/- 217) than in male (202 +/- 150) rats, but the numbers of unmyelinated axons were not significantly different. In normal sural nerves, the numbers of either all myelinated axons or thin myelinated axons did not significantly differ between the two sexes. Therefore, the more extensive collateral axon sprouting observed in female than in male rats is probably due to the higher sprouting capacity of thin myelinated sensory axons in females.
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Affiliation(s)
- U Kovacic
- Institute of Pathophysiology, Medical Faculty, University of Ljubljana, Zalosbreve;ka 4, 1000, Ljubljana, Slovenia
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Kovacic U, Bajrović F, Sketelj J. Recovery of cutaneous pain sensitivity after end-to-side nerve repair in the rat. J Neurosurg 1999; 91:857-62. [PMID: 10541245 DOI: 10.3171/jns.1999.91.5.0857] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The hypothesis that collaterally sprouting axons from an uninjured donor nerve may provide recovery of pain sensitivity in the skin after end-to-side nerve repair was investigated in rats. In addition, the effect of this technique on the donor nerve was examined. METHODS The distal stump of the transected peroneal nerve was sutured end to side to the intact sural nerve. No epineurial window or perineurial slit was made in the sural nerve at the site of coaptation. Other nerves in the leg were transected and ligated. Eighteen weeks later, the sural nerve was transected at a site distal from the coaptation site. The residual pain sensitivity in the peroneal innervation field in the instep was documented using the skin pinch test in three of 11 animals. The area of sensitivity encompassed 19 to 40% of the maximum nociceptive innervation area of the normal peroneal nerve. The nerve pinch test revealed functional sensory axons in all communicating peroneal nerves, in which 277+/-119 myelinated axons (mean +/- standard deviation) were found by histological investigation. CONCLUSIONS The authors conclude that at least partial recovery of sensory function due to collateral sprouting of axons after end-to-side nerve repair is possible in principle. However, the presence of functional sensory axons in the peroneal nerve stumps did not guarantee the recovery of skin sensitivity to pain in all animals. No functional or morphological evidence of an untoward effect of collateral sprouting into the end-to-side communicating nerve was detected in the axons of the donor nerve itself.
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Affiliation(s)
- U Kovacic
- Institute of Pathophysiology, University of Ljubljana, Slovenia
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