These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Fracture induces keratinocyte activation, proliferation, and expression of pro-nociceptive inflammatory mediators.
    Author: Li WW, Guo TZ, Li XQ, Kingery WS, Clark DJ.
    Journal: Pain; 2010 Dec; 151(3):843-852. PubMed ID: 20934254.
    Abstract:
    Tibia fracture in rats results in chronic vascular and nociceptive changes in the injured limb resembling complex regional pain syndrome (CRPS) and up-regulates expression of interleukin 1β (IL-1β), interleukin IL-6 (IL-6), tumor necrosis factor-α (TNF-α), and nerve growth factor-β (NGF-β) in the hindpaw skin. When fractured rats are treated with cytokine or NGF inhibitors nociceptive sensitization is blocked. Because there is no leukocyte infiltration in the hindpaw skin we postulated that resident skin cells produce the inflammatory mediators causing nociceptive sensitization after fracture. To test this hypothesis rats underwent distal tibia fracture and hindlimb casting for 4 weeks, then the hindpaw skin was harvested and immunostained for keratin, cytokines and NGF. BrdU staining was used to evaluate cell proliferation. Hindpaw nociceptive thresholds, edema, and temperature were tested before and up to 96h after intraplantar injections of IL-6 and TNF-α. Tibia fracture caused keratinocyte activation, proliferation, and up-regulated IL-1β, IL-6, TNF-α and NGF-β protein expression in the hindpaw keratinocytes. Local injections of IL-6 and TNF-α induced hindpaw mechanical allodynia lasting for several days and modest increases in temperature and edema. These data indicate that activated keratinocytes proliferate and express IL-1β, IL-6, TNF-α, and NGF-β after fracture and that excess amounts of inflammatory mediators in the skin cause sustained nociceptive sensitization. This is the first study demonstrating in vivo keratinocyte expression of IL-6, TNF-α and NGF-β in a CRPS model and we postulate that the keratinocyte is the primary cellular source for the inflammatory signals mediating cutaneous nociceptive sensitization in early CRPS.
    [Abstract] [Full Text] [Related] [New Search]