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Updated: Jun 1, 2026
10:41
A Hypoxia-Reoxygenation Injury Model in Self-Assembling Human Cardioids
Published on: March 17, 2026
Hyperoxia during early reperfusion does not increase ischemia/reperfusion injury
Lars Henrik Mariero1, Arkady Rutkovskiy, Kåre-Olav Stensløkken
1Faculty of Medicine, Department of Molecular Biosciences, University of Oslo, and Institute for Experimental Medical Research, Department of Surgery, Oslo University Hospital, Oslo, Norway. l.h.mariero@medisin.uio.no
Summary
Ventilating with 95% oxygen during reperfusion did not worsen heart damage in rats. This study found no increase in myocardial infarction size when using hyperoxia, suggesting it does not aggravate ischemia/reperfusion injury.
Area of Science:
- Cardiovascular Research
- Myocardial Ischemia and Reperfusion Injury
- Oxygen Therapy
Background:
- Oxygen is standard care for acute myocardial infarction, revascularization, and cardiac surgery.
- Reactive oxygen species mediate ischemia/reperfusion injury, raising concerns that increased oxygen might worsen damage.
- The theoretical risk of hyperoxia aggravating myocardial injury during reperfusion requires investigation.
Purpose of the Study:
- To test the hypothesis that ventilation with a hyperoxic gas at the start of reperfusion increases myocardial ischemia/reperfusion injury.
- To evaluate the effect of normobaric hyperoxia on infarct size and reperfusion arrhythmias in a rat model.
Main Methods:
- Rats underwent 40 minutes of regional myocardial ischemia followed by 120 minutes of reperfusion.
- The test group (n=10) received 95% oxygen (hyperoxia) during the late ischemia and early reperfusion phases.
- Control rats (n=8) received 40% oxygen (normoxia); infarct size was measured post-reperfusion.
Main Results:
- Normobaric hyperoxia did not significantly alter infarct size (20±8% vs. 24±8% of the area at risk).
- The incidence of lethal reperfusion arrhythmias was lower in the hyperoxia group (1/11) compared to the normoxia group (6/14), though not statistically significant (p=0.06).
- No increase in ischemia/reperfusion injury was observed with normobaric hyperoxia.
Conclusions:
- Normobaric hyperoxia administered during early reperfusion does not increase myocardial ischemia/reperfusion injury.
- The findings do not support the hypothesis that hyperoxia aggravates myocardial injury in this model.
- Further research may explore the potential anti-arrhythmic effects observed.
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