Glial Phosphorylated p38 MAP Kinase Mediates Pain in a Rat Model of Lumbar Disc Herniation and Induces Motor Dysfunction in a Rat Model of Lumbar Spinal Canal Stenosis

Study Design. Immunohistochemical and behavioral study using rat models of lumbar disc herniation and cauda equina syndrome. Objective. To investigate the expression of activated p38 mitogen-activated protein kinases (p38 MAP kinase; p38) in the spinal cord and to determine the effect of intrathecal administration of a specific p38 inhibitor on pain in a lumbar disc herniation model and on motor function and hypoalgesia in a spinal canal stenosis (SCS) model. Summary of Background Data. In pathologic lumbar disc herniation-induced neuropathic pain and compression of cauda equina-induced motor dysfunction and hypoalgesia caused by SCS, glia are activated and produce certain cytokines, including tumor necrosis factor-alpha (TNF-&agr;) and interleukins, which play a crucial role in the pathogenesis of nerve degeneration. p38 is phosphorylated by these cytokines, suggesting that it may play an important role in pain transmission and nerve degeneration. Here we have examined the role of p38 in rat models of lumbar disc herniation and SCS. Methods. Six-week-old male Sprague-Dawley rats were used. For the disc herniation model, autologous nucleus pulposus was applied to L5 nerve roots, which were then crushed. For the SCS model, a piece of silicon was placed under the lamina of the fourth lumbar vertebra. We assessed mechanical allodynia, hypoalgesia, and motor function using von Frey hairs, treadmill tests, and immunohistochemical localization of phosphorylated p38 (P-p38) in the cauda equina, dorsal root ganglion (DRG), and spinal cord, which were also double-stained with NeuN (neuronal marker), GFAP (astrocyte/Schwann cell marker), or isolectin B4 (IB4; microglia marker). We also examined the effects of intrathecal administration of a specific p38 inhibitor, FR167653, on nucleus pulposus-induced pain, hypoalgesia, and motor dysfunction following SCS. Results. We demonstrated that activated P-p38-immunoreactive cells in the spinal cord and cauda equina were not observed before nerve injury but appeared in the cauda equina, DRG, and spinal dorsal horn in the disc herniation and SCS models. Double-labeling revealed that most P-p38-immunoreactive cells were isolectin B4-labeled microglia and GFAP-immunoreactive Schwann cells. Intrathecal administration of the p38 inhibitor FR167653 decreased mechanical allodynia in the disc herniation model and improved hypoalgesia and intermittent motor dysfunction in the SCS model. Conclusions. Our findings suggest that activated p38 may play an important role in the involvement of microglia in the pathophysiology of pain following lumbar disc herniation and mechanical hypoalgesia, and motor nerve dysfunction of cauda equina following SCS.

[1]  J. Niinimäki,et al.  The Treatment of Disc Herniation-Induced Sciatica With Infliximab: One-Year Follow-up Results of FIRST II, a Randomized Controlled Trial , 2006, Spine.

[2]  Kazuhide Inoue.  The function of microglia through purinergic receptors: neuropathic pain and cytokine release. , 2006, Pharmacology & therapeutics.

[3]  J. Niinimäki,et al.  The Treatment of Disc Herniation-Induced Sciatica With Infliximab: Results of a Randomized, Controlled, 3-Month Follow-up Study , 2005, Spine.

[4]  F. Kayaselçuk,et al.  Analysis and prevalence of inflammatory cells in subtypes of lumbar disc herniations under cyclooxygenase-2 inhibitor therapy , 2005, Neurological research.

[5]  C. Sommer,et al.  Intraneural injection of interleukin-1β and tumor necrosis factor-alpha into rat sciatic nerve at physiological doses induces signs of neuropathic pain , 2005, Pain.

[6]  Yi Dai,et al.  Activation of p38 MAPK in primary afferent neurons by noxious stimulation and its involvement in the development of thermal hyperalgesia , 2005, Pain.

[7]  J. Niinimäki,et al.  Efficacy of Infliximab for Disc Herniation-Induced Sciatica: One-Year Follow-up , 2004, Spine.

[8]  S. Ohtori,et al.  Spinal neural cyclooxygenase-2 mediates pain caused in a rat model of lumbar disk herniation. , 2004, The journal of pain : official journal of the American Pain Society.

[9]  R. Myers,et al.  Experimental Spinal Stenosis: Relationship Between Degree of Cauda Equina Compression, Neuropathology, and Pain , 2004, Spine.

[10]  R. Myers,et al.  TNF-&agr; and TNF-&agr; Receptor Type 1 Upregulation in Glia and Neurons After Peripheral Nerve Injury: Studies in Murine DRG and Spinal Cord , 2004 .

[11]  R. Myers,et al.  TNF-alpha and TNF-alpha receptor type 1 upregulation in glia and neurons after peripheral nerve injury: studies in murine DRG and spinal cord. , 2004, Spine.

[12]  R. Myers,et al.  Inhibition of p38 MAP kinase activity enhances axonal regeneration , 2003, Experimental Neurology.

[13]  N. Calcutt,et al.  Activation of p38 mitogen‐activated protein kinase in spinal microglia is a critical link in inflammation‐induced spinal pain processing , 2003, Journal of neurochemistry.

[14]  Yuzuru Takahashi,et al.  Dermatomes and the central organization of dermatomes and body surface regions in the spinal cord dorsal horn in rats , 2003, The Journal of comparative neurology.

[15]  L. Sorkin,et al.  Tumor Necrosis Factor-α Induces Mechanical Allodynia after Spinal Nerve Ligation by Activation of p38 MAPK in Primary Sensory Neurons , 2003, The Journal of Neuroscience.

[16]  L. Sorkin,et al.  Tumor necrosis factor-alpha induces mechanical allodynia after spinal nerve ligation by activation of p38 MAPK in primary sensory neurons. , 2003, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[17]  H. Lee,et al.  Activation of p38 MAP kinase in the rat dorsal root ganglia and spinal cord following peripheral inflammation and nerve injury , 2002, Neuroreport.

[18]  C. Woolf,et al.  p38 MAPK Activation by NGF in Primary Sensory Neurons after Inflammation Increases TRPV1 Levels and Maintains Heat Hyperalgesia , 2002, Neuron.

[19]  S. Rotshenker,et al.  The Cytokine Network of Wallerian Degeneration: Tumor Necrosis Factor-α, Interleukin-1α, and Interleukin-1β , 2002, The Journal of Neuroscience.

[20]  S. M. McFarlane,et al.  TNF-α receptors simultaneously activate Ca2+ mobilisation and stress kinases in cultured sensory neurones , 2002, Neuropharmacology.

[21]  Linda R Watkins,et al.  Beyond neurons: evidence that immune and glial cells contribute to pathological pain states. , 2002, Physiological reviews.

[22]  S. Rotshenker,et al.  The cytokine network of Wallerian degeneration: tumor necrosis factor-alpha, interleukin-1alpha, and interleukin-1beta. , 2002, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[23]  T. Takebayashi,et al.  Effect of Nucleus Pulposus on the Neural Activity of Dorsal Root Ganglion , 2001, Spine.

[24]  R. Myers,et al.  Prevention of Compartment Syndrome in Dorsal Root Ganglia Caused by Exposure to Nucleus Pulposus , 2001, Spine.

[25]  R. Myers,et al.  Exogenous Tumor Necrosis Factor-Alpha Mimics Nucleus Pulposus-Induced Neuropathology: Molecular, Histologic, and Behavioral Comparisons in Rats , 2000, Spine.

[26]  A. Minamide,et al.  Mechanical compression of the lumbar nerve root alters pain‐related behaviors induced by the nucleus pulposus in the rat , 2000, Journal of orthopaedic research : official publication of the Orthopaedic Research Society.

[27]  J. Deleo,et al.  The Effect of Site and Type of Nerve Injury on Spinal Glial Activation and Neuropathic Pain Behavior , 1999, Experimental Neurology.

[28]  L. Sorkin,et al.  Hyperalgesic actions of cytokines on peripheral nerves , 1999 .

[29]  C. Widmann,et al.  Mitogen-activated protein kinase: conservation of a three-kinase module from yeast to human. , 1999, Physiological reviews.

[30]  K. Olmarker,et al.  Tumor Necrosis Factor α and Nucleus‐Pulposus‐Induced Nerve Root Injury , 1998 .

[31]  J. Dean,et al.  A p38 MAP kinase inhibitor regulates stability of interleukin‐1‐induced cyclooxygenase‐2 mRNA , 1998, FEBS letters.

[32]  R. Fields.  Effects of ion channel activity on development of dorsal root ganglion neurons. , 1998, Journal of neurobiology.

[33]  John C. Lee,et al.  Extracellular Signal-Regulated Kinase and p38 Subgroups of Mitogen-Activated Protein Kinases Regulate Inducible Nitric Oxide Synthase and Tumor Necrosis Factor-α Gene Expression in Endotoxin-Stimulated Primary Glial Cultures , 1998, The Journal of Neuroscience.

[34]  K. Olmarker,et al.  Tumor necrosis factor alpha and nucleus-pulposus-induced nerve root injury. , 1998, Spine.

[35]  S. Rotshenker,et al.  Murine Nucleus Pulposus‐Derived Cells Secrete Interleukins‐1‐β, ‐6, and ‐10 and Granulocyte‐Macrophage Colony‐Stimulating Factor in Cell Culture , 1997, Spine.

[36]  J. Weinstein,et al.  Pathomechanism of Pain‐Related Behavior Produced by Allografts of Intervertebral Disc in the Rat , 1996, Spine.

[37]  T. Kakiuchi,et al.  Inflammatory Cytokines in the Herniated Disc of the Lumbar Spine , 1996, Spine.

[38]  K. Olmarker,et al.  A Model for Acute, Chronic, and Delayed Graded Compression of the Dog Cauda Equina: Presentation of the Gross, Microscopic, and Vascular Anatomy of the Dog Cauda Equina and Accuracy in Pressure Transmission of the Compression Model , 1995, Spine.

[39]  E. Benveniste,et al.  Differential modulation of astrocyte cytokine gene expression by TGF-beta. , 1994, Journal of immunology.

[40]  Jerry L. Adams,et al.  A protein kinase involved in the regulation of inflammatory cytokine biosynthesis , 1994, Nature.

[41]  T. Yaksh,et al.  Quantitative assessment of tactile allodynia in the rat paw , 1994, Journal of Neuroscience Methods.

[42]  C. Nordborg,et al.  Autologous nucleus pulposus induces neurophysiologic and histologic changes in porcine cauda equina nerve roots. , 1993, Spine.

[43]  W. Dixon,et al.  Efficient analysis of experimental observations. , 1980, Annual review of pharmacology and toxicology.