Related Experiment Video
Updated: Jun 20, 2026
Model of Ischemia and Reperfusion Injury in Rabbits
Published on: November 3, 2023
[Preconditioning of morphine protects rabbit myocardium from ischemia-reperfusion injury]
Xiang-hang LU1, Ke RAN, Jun-mei XU
1Department of Anesthesiology, The Second Xiangya Hospital, Central South University, Changsha 410011.
Objective:
To investigate the protective effects of preconditioning morphine on rabbit myocardium during ischemia-reperfusion.
Methods:
Thirty New Zealand male white rabbits were randomly assigned to three groups: control, I/R and morphine groups. In morphine group 1.0 mg/kg morphine was given preoperationaly, in control and I/R groups 1.0 ml/kg NS was given. Twenty-four hours later rabbits in morphine and I/R groups underwent 40 min of coronary occlusion followed by 2 hours of reperfusion; for control group only sham operation was performed. At the end of the reperfusion, infarct size (IS) and area at risk (AAR) were defined by Evans blue and TTC staining. At the end of the reperfusion blood samples were taken for determination of plasma SOD activity and MDA levels. The heart was harvested and levels of the HSP27 were determined by Western blot, and the heart ultrastructures were observed under the electron microscopy.
Results:
Compared with I/R group,morphine significantly reduced infarct size (21.5%+/-2.4% Compared with 37.8%+/-1.7%, P<0.05). The morphine had a lower level of MDA and higher levels of SOD and HSP27 than those in I/R.
Conclusion:
Preconditioning of morphine demonstrates cardioprotective effect on ischemia/reperfusion injury, which may be associated with increased HSP27 levels in the heart.
Insights
Preconditioning with morphine significantly reduced heart damage from ischemia-reperfusion injury in rabbits. This cardioprotective effect may be linked to increased heat shock protein 27 (HSP27) levels.
Area of Science:
- Cardiovascular Physiology
- Pharmacology
- Cellular Biology
Context:
- Myocardial ischemia-reperfusion (I/R) injury is a major cause of heart damage.
- Preconditioning is a phenomenon where brief exposure to a stressor protects against subsequent I/R injury.
- Morphine is an opioid analgesic with potential cardioprotective properties.
Purpose:
- To investigate the cardioprotective effects of preconditioning with morphine on myocardial I/R injury in a rabbit model.
- To assess the impact of morphine preconditioning on infarct size, oxidative stress markers, and heat shock protein 27 (HSP27) levels.
Summary:
- Morphine preconditioning (1.0 mg/kg) significantly reduced infarct size in rabbits subjected to 40 minutes of coronary occlusion and 2 hours of reperfusion compared to the I/R group (21.5% vs. 37.8%, P<0.05).
- The morphine group exhibited lower plasma malondialdehyde (MDA) levels and higher superoxide dismutase (SOD) activity and cardiac HSP27 levels compared to the I/R group.
- Electron microscopy revealed preserved heart ultrastructure in the morphine group.
Impact:
- Preconditioning with morphine demonstrates a significant cardioprotective effect against myocardial I/R injury.
- The protective mechanism may involve the upregulation of HSP27, a key cellular stress protein.
- These findings suggest a potential therapeutic strategy for mitigating heart damage during ischemic events.
