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Barbe MF, Chen FL, Loomis RH, Harris MY, Kim BM, Xie K, Hilliard BA, McGonagle ER, Bailey TD, Gares RP, Van Der Bas M, Kalicharan BA, Holt-Bright L, Stone LS, Hodges PW, Klyne DM. Characterization of pain-related behaviors in a rat model of acute-to-chronic low back pain: single vs. multi-level disc injury. FRONTIERS IN PAIN RESEARCH 2024; 5:1394017. [PMID: 38770243 PMCID: PMC11102983 DOI: 10.3389/fpain.2024.1394017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 04/16/2024] [Indexed: 05/22/2024] Open
Abstract
Introduction Low back pain is the most common type of chronic pain. We examined pain-related behaviors across 18 weeks in rats that received injury to one or two lumbar intervertebral discs (IVD) to determine if multi-level disc injuries enhance/prolong pain. Methods Twenty-three Sprague-Dawley adult female rats were used: 8 received disc puncture (DP) of one lumbar IVD (L5/6, DP-1); 8 received DP of two lumbar IVDs (L4/5 & L5/6, DP-2); 8 underwent sham surgery. Results DP-2 rats showed local (low back) sensitivity to pressure at 6- and 12-weeks post-injury, and remote sensitivity to pressure (upper thighs) at 12- and 18-weeks and touch (hind paws) at 6, 12 and 18-weeks. DP-1 rats showed local and remote pressure sensitivity at 12-weeks only (and no tactile sensitivity), relative to Sham DP rats. Both DP groups showed reduced distance traveled during gait testing over multiple weeks, compared to pre-injury; only DP-2 rats showed reduced distance relative to Sham DP rats at 12-weeks. DP-2 rats displayed reduced positive interactions with a novel adult female rat at 3-weeks and hesitation and freezing during gait assays from 6-weeks onwards. At study end (18-weeks), radiological and histological analyses revealed reduced disc height and degeneration of punctured IVDs. Serum BDNF and TNFα levels were higher at 18-weeks in DP-2 rats, relative to Sham DP rats, and levels correlated positively with remote sensitivity in hind paws (tactile) and thighs (pressure). Discussion Thus, multi-level disc injuries resulted in earlier, prolonged and greater discomfort locally and remotely, than single-level disc injury. BDNF and TNFα may have contributing roles.
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Affiliation(s)
- Mary F. Barbe
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Frank Liu Chen
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Regina H. Loomis
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Michele Y. Harris
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Brandon M. Kim
- Medical Doctor Program, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Kevin Xie
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Brendan A. Hilliard
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Elizabeth R. McGonagle
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Taylor D. Bailey
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Ryan P. Gares
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Megan Van Der Bas
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Betsy A. Kalicharan
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Lewis Holt-Bright
- Aging + Cardiovascular Discovery Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Laura S. Stone
- Department of Anesthesiology, University of Minnesota, Minneapolis, MN, United States
| | - Paul W. Hodges
- NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - David M. Klyne
- NHMRC Centre of Clinical Research Excellence in Spinal Pain, Injury and Health, School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, QLD, Australia
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Millecamps M, Sotocinal SG, Austin JS, Stone LS, Mogil JS. Sex-specific effects of neuropathic pain on long-term pain behavior and mortality in mice. Pain 2023; 164:577-586. [PMID: 35916733 DOI: 10.1097/j.pain.0000000000002742] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/15/2022] [Indexed: 11/26/2022]
Abstract
ABSTRACT Human epidemiological studies suggest that chronic pain can increase mortality risk. We investigated whether this was true in mice so that underlying mechanisms might be identified. At 10 weeks of age, C57BL/6 mice of both sexes received sham or spared nerve injury (SNI) surgery producing neuropathic pain. Mice were weighed monthly, tested behaviorally for mechanical and cold sensitivity and guarding behavior every 3 months postsurgery, and otherwise left undisturbed in their cages until death by natural causes. Evidence of pain over the lifespan displayed a strikingly sex-specific pattern. Male mice displayed largely stable mechanical and cold hypersensitivity and guarding at 6 to 30 months post-SNI. By contrast, female mice displayed a biphasic temporal pattern of mechanical hypersensitivity and guarding behavior, with a complete resolution of SNI-induced pain behavior at 6 to 9 months post-SNI followed by the return of pain thereafter. Mouse lifespan was not significantly altered by SNI in either sex nor was frailty as assessed by cage inspection in the last 6 months of life. However, in male mice with SNI, we observe a significant correlation between average lifetime mechanical hypersensitivity and lifespan, such that death occurred sooner in male mice exhibiting more evidence of chronic pain. This relationship was not observed in female SNI mice nor in sham-operated mice of either sex. This experiment is the first to investigate pain behavior over an entire adult lifetime and suggests that biology of relevance to human chronic pain is being ignored by the very short timespans of most extant preclinical pain research.
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Affiliation(s)
- Magali Millecamps
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
| | - Susana G Sotocinal
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
| | | | - Laura S Stone
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Department of Anesthesiology, University of Minnesota, Minneapolis, MN, United States
| | - Jeffrey S Mogil
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Departments of Psychology and Anesthesia, McGill University, Montreal, QC, Canada
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