Real-Time Monitoring of Tissue Oxygenation During Hyperbaric Oxygen Exposure Using In Vivo EPR Oximetry

Area of Science:

• Biomedical Engineering
• Physiology
• Oncology

Background:

• Hyperbaric oxygen (HBO) therapy enhances blood oxygen levels for treating conditions like chronic wounds and impaired healing.
• Accurate, real-time measurement of tissue oxygen tension (pO2) under hyperbaric conditions is a significant technical challenge.

Purpose of the Study:

• To develop and validate a specialized small-animal hyperbaric chamber for in vivo electron paramagnetic resonance (EPR) oximetry.
• To enable precise, real-time monitoring of tissue pO2 under clinically relevant hyperbaric conditions.

Main Methods:

• A novel small-animal hyperbaric chamber compatible with in vivo EPR oximetry was designed.
• Customized OxyTrack oxygen detectors were used to measure pO2 in mouse skeletal muscle and tumor tissue.
• Animals were exposed to varying oxygen concentrations (21% and 100% O2) at normobaric and 2 atmospheres absolute (ATA) pressures.

Main Results:

• The hyperbaric chamber operated safely up to 2 ATA, allowing stable, real-time pO2 monitoring.
• Tumor pO2 in B16-F10 melanoma significantly increased with HBO, showing pressure-dependent responses.
• Skeletal muscle tissue exhibited substantial pressure-dependent increases in pO2, while SCC7 tumors showed minimal response.

Conclusions:

• The developed hyperbaric chamber facilitates real-time, tissue-specific assessment of oxygen dynamics under HBO.
• This technology can aid in optimizing HBO protocols and advancing research on oxygen-modulated therapies, particularly for solid tumors.
• The findings support translational studies investigating the impact of oxygen on tumor response to radiation and chemotherapy.