Tissue Oxygen Profiling Using Electron Paramagnetic Resonance Oximetry to Improve Wound Healing After Radiation

The objective of this study is to describe the oxygen profile obtained by electron paramagnetic resonance (EPR) oximetry of tissue after radiation, surgery, and hyperbaric oxygen therapy (HBOT) and its relationship to wound healing in a rodent model. The study design is rodent model for wound healing. A rodent model for wound healing was used for oxygen measurements before and after various treatments. EPR measurements and biopsies of normal vs irradiated and flap vs non-flap tissues were taken at 1–3-week intervals for 12 weeks. Wound healing was evaluated by gross photos, histology, and immunostaining. Student’s t test and a linear mixed model were used to compare oxygen levels and gross healing with radiation exposure. A Proportional Odds model was also used to calculate odds ratio toward better wound-healing rate with radiation exposure. In the rodent model, at 1–3 weeks after irradiation, the mean tissue oxygen measurement was significantly lower in irradiated versus non-irradiated leg tissue. There was a significant difference in oxygenation between flap and non-flap tissue in an irradiated bed at 1 and 3 weeks after surgery. On gross evaluation, wound healing from z -plasty flap was significantly worse in irradiated tissue compared to non-irradiated tissue. A rodent model for wound healing showed that radiation resulted in decreased tissue oxygenation at 1–3 weeks after irradiation. Wound healing was compromised in irradiated tissue at earlier time points when tissue oxygenation was lower. Oxygen profiling with EPR oximetry can be used to identify timing of oxygen interventions to improve wound healing. Level of evidence is NA, animal studies.