In vivo effect of hyperbaric oxygen on wound angiogenesis and epithelialization

Wound Repair Regen. Mar-Apr 2009;17(2):179-84. doi: 10.1111/j.1524-475X.2009.00455.x.


Hyperbaric oxygen (HBO) therapy is increasingly being used in different areas of medical practice. While demonstrated to be effective in several settings, its mechanism of action is not well understood. In the present study, we determined the effects of HBO on wound epithelialization and neovascularization in an in vivo hairless mouse ear "impaired" wound model. To impair wound healing, macrophages were depleted by pretreatment with iota-carrageenan. Wound epithelialization and neovascularization were measured using intravital microscopy and computerized planimetry. Metalloproteinase-2 (MMP-2), MMP-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), and tumor necrosis factor-alpha (TNF-alpha) were measured on days 2 and 7 using immunohistochemistry. In nonimpaired healing wounds, the rate of epithelialization and neovascularization was significantly accelerated in the groups treated with HBO. Time to wound closure was significantly delayed in impaired compared with nonimpaired healing wounds and HBO treatment completely reversed this delay. Neither HBO treatment nor macrophage depletion caused significant alterations in MMP-2 expression in wounds. In contrast, TNF-alpha, MMP-9, and TIMP-1 were significantly up-regulated in the impaired healing group receiving HBO treatment. These results show that HBO therapy effectively reversed the negative effect exerted by macrophage reduction on wound epithelialization and neovascularization. This beneficial effect could be due to stimulation of TNF-alpha production and, to a lesser degree due to release of metalloproteinases.

MeSH terms

  • Analysis of Variance
  • Animals
  • Carrageenan / adverse effects
  • Chronic Disease
  • Disease Models, Animal*
  • Ear* / blood supply
  • Ear* / injuries
  • Granulation Tissue / pathology
  • Hyperbaric Oxygenation / methods*
  • Immunohistochemistry
  • Macrophages / drug effects
  • Macrophages / immunology
  • Male
  • Matrix Metalloproteinase 2 / analysis
  • Matrix Metalloproteinase 9 / analysis
  • Mice
  • Mice, Hairless
  • Microscopy, Video
  • Neovascularization, Physiologic / physiology*
  • Statistics, Nonparametric
  • Time Factors
  • Tissue Inhibitor of Metalloproteinase-1 / analysis
  • Tumor Necrosis Factor-alpha / analysis
  • Wound Healing / physiology*
  • Wounds and Injuries / pathology
  • Wounds and Injuries / therapy*


  • Tissue Inhibitor of Metalloproteinase-1
  • Tumor Necrosis Factor-alpha
  • Carrageenan
  • Matrix Metalloproteinase 2
  • Matrix Metalloproteinase 9