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Braz JM, Hamel K, Craik V, Rodriguez-Rosado S, Bhardwaj K, Jewell M, Bieri G, Villeda SA, Basbaum AI. Pain and Itch Processing in Aged Mice. THE JOURNAL OF PAIN 2024; 25:53-63. [PMID: 37482234 DOI: 10.1016/j.jpain.2023.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/30/2023] [Accepted: 07/18/2023] [Indexed: 07/25/2023]
Abstract
Most reports agree that aging negatively impacts pain processing and that the prevalence of chronic pain increases significantly with age. To improve current therapies, it is critical that aged animals be included in preclinical studies. Here we compared sensitivities to pain and itch-provoking stimuli in naïve and injured young and aged mice. Surprisingly, we found that in the absence of injury, aged male and female mice are significantly less responsive to mechanical stimuli and, in females, also to noxious thermal (heat) stimuli. In both older male and female mice, compared to younger (6-month-old mice), we also recorded reduced pruritogen-evoked scratching. On the other hand, after nerve injury, aged mice nevertheless developed significant mechanical hypersensitivity. Interestingly, however, and in contrast to young mice, aged mice developed both ipsilateral and contralateral postinjury mechanical allodynia. In a parallel immunohistochemical analysis of microglial and astrocyte markers, we found that the ipsilateral to the contralateral ratio of nerve injury-induced expression decreased with age. That observation is consistent with our finding of contralateral hypersensitivity after nerve injury in the aged but not the young mice. We conclude that aging has opposite effects on baseline versus postinjury pain and itch processing. PERSPECTIVE: Aged male and female mice (22-24 months) are less sensitive to mechanical, thermal (heat), and itch-provoking stimuli than are younger mice (6 months).
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Affiliation(s)
- João M Braz
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Katherine Hamel
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Veronica Craik
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Sian Rodriguez-Rosado
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Karnika Bhardwaj
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Madison Jewell
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Gregor Bieri
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Saul A Villeda
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, San Francisco, California
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Galbavy W, Kaczocha M, Puopolo M, Liu L, Rebecchi MJ. Neuroimmune and Neuropathic Responses of Spinal Cord and Dorsal Root Ganglia in Middle Age. PLoS One 2015; 10:e0134394. [PMID: 26241743 PMCID: PMC4524632 DOI: 10.1371/journal.pone.0134394] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/08/2015] [Indexed: 02/07/2023] Open
Abstract
Prior studies of aging and neuropathic injury have focused on senescent animals compared to young adults, while changes in middle age, particularly in the dorsal root ganglia (DRG), have remained largely unexplored. 14 neuroimmune mRNA markers, previously associated with peripheral nerve injury, were measured in multiplex assays of lumbar spinal cord (LSC), and DRG from young and middle-aged (3, 17 month) naïve rats, or from rats subjected to chronic constriction injury (CCI) of the sciatic nerve (after 7 days), or from aged-matched sham controls. Results showed that CD2, CD3e, CD68, CD45, TNF-α, IL6, CCL2, ATF3 and TGFβ1 mRNA levels were substantially elevated in LSC from naïve middle-aged animals compared to young adults. Similarly, LSC samples from older sham animals showed increased levels of T-cell and microglial/macrophage markers. CCI induced further increases in CCL2, and IL6, and elevated ATF3 mRNA levels in LSC of young and middle-aged adults. Immunofluorescence images of dorsal horn microglia from middle-aged naïve or sham rats were typically hypertrophic with mostly thickened, de-ramified processes, similar to microglia following CCI. Unlike the spinal cord, marker expression profiles in naïve DRG were unchanged across age (except increased ATF3); whereas, levels of GFAP protein, localized to satellite glia, were highly elevated in middle age, but independent of nerve injury. Most neuroimmune markers were elevated in DRG following CCI in young adults, yet middle-aged animals showed little response to injury. No age-related changes in nociception (heat, cold, mechanical) were observed in naïve adults, or at days 3 or 7 post-CCI. The patterns of marker expression and microglial morphologies in healthy middle age are consistent with development of a para-inflammatory state involving microglial activation and T-cell marker elevation in the dorsal horn, and neuronal stress and satellite cell activation in the DRG. These changes, however, did not affect the establishment of neuropathic pain.
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Affiliation(s)
- William Galbavy
- Department of Anesthesiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Martin Kaczocha
- Department of Anesthesiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Michelino Puopolo
- Department of Anesthesiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Lixin Liu
- Department of Anesthesiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Mario J Rebecchi
- Department of Anesthesiology, Stony Brook University, Stony Brook, New York, United States of America
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Mahmoud MA, Fahmy GH, Moftah MZ, Sabry I. Distribution of nitric oxide-producing cells along spinal cord in urodeles. Front Cell Neurosci 2014; 8:299. [PMID: 25309330 PMCID: PMC4174862 DOI: 10.3389/fncel.2014.00299] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 09/05/2014] [Indexed: 11/24/2022] Open
Abstract
Nitric oxide is a unique neurotransmitter, which participates in many physiological and pathological processes in the organism. There are little data about the neuronal nitric oxide synthase immunoreactivity in the spinal cord of amphibians. In this respect, the present study aims to investigate the distribution of nitric oxide producing cells in the spinal cord of urodele and to find out the possibility of a functional locomotory role to this neurotransmitter. The results of the present study demonstrate a specific pattern of NADPH-d labeling in the selected amphibian model throughout the spinal cord length as NADPH-d-producing cells and fibers were present in almost all segments of the spinal cord of the salamander investigated. However, their number, cytological characteristics and labeling intensity varied significantly. It was noticed that the NO-producing cells (NO-PC) were accumulated in the ventral side of certain segments in the spinal cord corresponding to the brachial and sacral plexuses. In addition, the number of NO-PC was found to be increased also at the beginning of the tail and this could be due to the fact that salamanders are tetrapods having bimodal locomotion, namely swimming and walking.
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Affiliation(s)
- Mayada A Mahmoud
- Faculty of Medicine, Institut de Neurosciences des Systèmes, Unités Mixtes de Recherche Institut National de la Santé et de la Recherche Médicale 1106, Aix-Marseille University Marseille, France
| | - Gehan H Fahmy
- Zoology Department, Faculty of Science, Alexandria University Alexandria, Egypt
| | - Marie Z Moftah
- Zoology Department, Faculty of Science, Alexandria University Alexandria, Egypt
| | - Ismail Sabry
- Zoology Department, Faculty of Science, Alexandria University Alexandria, Egypt
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Regional variations and age-related changes in arginine metabolism in the rat brain stem and spinal cord. Neuroscience 2013; 252:98-108. [DOI: 10.1016/j.neuroscience.2013.08.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 07/26/2013] [Accepted: 08/01/2013] [Indexed: 01/08/2023]
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Yezierski RP. The effects of age on pain sensitivity: preclinical studies. PAIN MEDICINE 2013; 13 Suppl 2:S27-36. [PMID: 22497745 DOI: 10.1111/j.1526-4637.2011.01311.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Preclinical studies of pain and aging represent an area of research where considerations of age, strain, gender, and method of behavioral assessment are but some of the challenges that must be addressed. The results of studies related to the impact of age on pain sensitivity have ranged from increased to decreased sensitivity to no change. Examining the design of these studies one discovers that cross-sectional designs using animals of different ages have been used to evaluate age-related effects in normal animals as well as animals with inflammatory and neuropathic pain conditions. In the present review a summary of these studies is presented along with a discussion of potential mechanisms responsible for changes that have been described. OUTCOME MEASURES The dominant method of behavioral assessment in the majority of studies involving rodents has been reflex-based strategies that unfortunately do not reveal the same effects of experimental manipulations known to affect pain sensitivity in humans. A comparison of results obtained with reflex-based methods versus those obtained with cortically dependent operant methods reveals significant differences. CONCLUSIONS Increases in pain sensitivity under different experimental conditions have been suggested to result from age-related anatomical, physiological, and biochemical changes as well as compensatory changes in homeostatic mechanisms and intrinsic plasticity of somatosensory pathways involved in the processing and perception of pain. Other factors that may contribute to the impact of age on pain sensitivity include dysregulation of the hypothalamic-pituitary-adrenal axis and changes in autonomic function that occur with advancing age. In the future translational research in the field of pain and aging will need to focus on establishing clinically relevant animal models and assessment strategies to evaluate the causal relationships between the biological changes associated with advancing age and the varied behavioral changes in pain sensitivity.
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Affiliation(s)
- Robert P Yezierski
- Department of Orthodontics, Comprehensive Center for Pain Research, University of Florida, Gainesville, Florida 32610, USA.
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Alterations in nitric oxide synthase in the aged CNS. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:718976. [PMID: 22829960 PMCID: PMC3399597 DOI: 10.1155/2012/718976] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 05/03/2012] [Accepted: 06/05/2012] [Indexed: 01/27/2023]
Abstract
Aging is associated with neuronal loss, gross weight reduction of the brain, and glial proliferation in the cortex, all of which lead to functional changes in the brain. It is known that oxidative stress is a critical factor in the pathogenesis of aging; additionally, growing evidence suggests that excessive nitric oxide (NO) production contributes to the aging process. However, it is still unclear how NO plays a role in the aging process. This paper describes age-related changes in the activity of NADPH-diaphorase (NADPH-d), a marker for neurons containing nitric oxide synthase (NOS), in many CNS regions. Understanding these changes may provide a novel perspective in identifying the aging mechanism.
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Yezierski RP, King CD, Morgan D, Carter CS, Vierck CJ. Effects of age on thermal sensitivity in the rat. J Gerontol A Biol Sci Med Sci 2010; 65:353-62. [PMID: 20185437 PMCID: PMC2844063 DOI: 10.1093/gerona/glq024] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Accepted: 01/27/2010] [Indexed: 01/06/2023] Open
Abstract
Age-dependent changes in thermal sensitivity were evaluated with reflex- and operant-based assessment strategies in animals ranging in age from 8 to 32 months. The impact of inflammatory injury on thermal sensitivity was also determined in animals of different ages. The results showed that operant measures of escape behavior are needed to demonstrate significant changes in thermal sensitivity across the life span of female Long-Evans rats. Increased escape from both heat (44.5 degrees C) and cold (1.5 degrees C-15 degrees C) was observed for older animals, with a greater relative increase in sensitivity to cold. Physical performance deficits were demonstrated with aging but were not associated with changes in escape responding. Reflex responding to cold stimulation was impaired in older animals but was also influenced by physical disabilities. Reflex responding to heat was not affected by increasing age. Inflammation induced by formalin injections in the dorsal hindpaw increased thermal sensitivity significantly more in older animals than in their younger counterparts.
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Affiliation(s)
- R P Yezierski
- Department of Orthodontics, University of Florida, 1600 SW Archer Road, PO Box 100444, Gainesville, FL 32610, USA.
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Tan H, He J, Wang S, Hirata K, Yang Z, Kuraoka A, Kawabuchi M. Age-related NADPH-diaphorase positive bodies in the lumbosacral spinal cord of aged rats. ACTA ACUST UNITED AC 2007; 69:297-310. [PMID: 17372386 DOI: 10.1679/aohc.69.297] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In the course of a morphological investigation of age-related changes in the rat spinal cord, using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry, we found abundant NADPH-d positive bodies, which were characteristically expressed in the aged lumbosacral spinal cord. Together with a normally stained fiber network and a few neurons, the dense, spheroidal NADPH-d positive bodies occurred in portions of the sacral dorsal spinal cords, such as the dorsal commissural nucleus, intermediolateral nuclei, and superficial dorsal horn, and were scattered throughout the dorsal white column. These NADPH-d positive bodies were occasionally observed in a fibrous structure. Two morphologically distinctive subsets of NADPH-d positive bodies were noted in the spinal cord of rats aged 8 to 36 months: 1) highly-dense spheroidal shapes with sharp edges; 2) moderately-dense spheroidal or multiangular shapes with a central "core" and a peripheral "halo". The quantitative analysis, particularly the stereological measurement, confirmed a gradual increase in the incidence and size of NADPH-d positive bodies with increasing age. With nNOS immunohistochemistry, no corresponding structures to NADPH-d positive bodies were detected in aged rats; thus NADPH-d activity is not always specific to the NO-containing neural structures. The major distribution of the NADPH-d positive bodies in the aged lumbosacral spinal cord indicates some anomalous changes in the neurite, which might account for a disturbance in the aging pathway of the autonomic and sensory nerve in the pelvic visceral organs.
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Affiliation(s)
- Huibing Tan
- Department of Anatomy and Cell Biology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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