Systemic Antiinflammatory Corticosteroid Reduces Mechanical Pain Behavior, Sympathetic Sprouting, and Elevation of Proinflammatory Cytokines in a Rat Model of Neuropathic Pain
Open Access
- 1 September 2007
- journal article
- laboratory investigations
- Published by Wolters Kluwer Health in Anesthesiology
- Vol. 107 (3), 469-477
- https://doi.org/10.1097/01.anes.0000278907.37774.8d
Abstract
Chronic pain models are commonly defined as either nerve-injury or inflammation models, but recent work suggests inflammatory processes are important in nerve injury-induced pain. In the rat spinal nerve ligation model, the authors examined effects of systemic corticosteroid triamcinolone acetonide (TA) on the cytokine protein profile and sympathetic sprouting in the axotomized sensory ganglia, excitability of sensory neurons, and mechanical sensitivity. By postoperative day 3, marked increases (5- to 16-fold) in monocyte chemoattractant protein-1, growth-related oncogene (GRO/KC or CXCL1), and interleukin (IL)-6 were observed, whereas IL-4 and IL-2 levels fell more than fourfold. The increased cytokines and number of sympathetic basket formations in the sensory ganglia were reduced toward normal values by TA given starting at the time of injury. Interleukin-4 and IL-2 levels were not restored by TA. Systemic TA also reduced the firing rate and incidence of bursting activity, but not the overall incidence of spontaneous activity, in large- and medium-sized neurons. Mechanical hypersensitivity on postoperative day 3 was reduced by TA, and some effect could still be observed 4 days after cessation of TA. However, starting TA at day 7 was ineffective. Several components of the spinal nerve injury model are responsive to corticosteroid, suggesting inflammatory processes are important in the development of neuropathic pain. The observation that TA was effective when given starting at the time of injury suggests that steroid treatment might alter the development of chronic pain after surgical procedures that involve nerve injury, such as amputation or hernia repair.Keywords
This publication has 52 references indexed in Scilit:
- Sympathetic Sprouting Near Sensory Neurons After Nerve Injury Occurs Preferentially on Spontaneously Active Cells and Is Reduced by Early Nerve BlockJournal of Neurophysiology, 2007
- Robust increase of cutaneous sensitivity, cytokine production and sympathetic sprouting in rats with localized inflammatory irritation of the spinal gangliaNeuroscience, 2006
- Effect of betamethasone on neuropathic pain and cerebral expression of NF-κB and cytokinesNeuroscience Letters, 2006
- Expression of Central Glucocorticoid Receptors after Peripheral Nerve Injury Contributes to Neuropathic Pain Behaviors in RatsJournal of Neuroscience, 2004
- Cytokines and acute neurodegenerationNature Reviews Neuroscience, 2001
- Glucocorticoid Inhibition of Neuropathic Hyperalgesia and Spinal Fos ExpressionPublished by Wolters Kluwer Health ,2001
- Effect of local methylprednisolone on pain in a nerve injury modelaA pilot studyRegional Anesthesia & Pain Medicine, 1997
- Role of peri-axonal inflammation in the development of thermal hyperalgesia and guarding behavior in a rat model of neuropathic painNeuroscience Letters, 1995
- Responses of macrophages in rat dorsal root ganglia following peripheral nerve injuryJournal of Neurocytology, 1993
- Ongoing activity in severed nerves: source and variation with timeBrain Research, 1978