Related Experiment Video
Updated: Jun 25, 2026
Model of Ischemia and Reperfusion Injury in Rabbits
Published on: November 3, 2023
[Delayed protective effect of morphine preconditioning on rabbit myocardium]
Limin Long1, Dingquan Zou, Rong Tan
1Department of Geriatrics , Second Xiangya Hospital, Central South University, Changsha 410011, China.
Objective:
To investigate whether morphine preconditioning has the delayed protective effect on rabbit myocardium.
Methods:
Thirty New Zealand white rabbits were randomly divided into a NS group, a Mor-12 group and a Mor-24 group (n=10). In the Mor-12 group and Mor-24 group, morphine (3 mg/kg) was infused into rabbits, while the same volume of normal saline (NS) was given to rabbits in the NS group. Twelve hours after morphine infusion in the Mor-12 group, 24 h after NS or morphine infusion in the NS group and Mor-24 group, rabbits were subjected to 30 min left anterior descending coronary artery occlusions and were reperfused for 120 min. In 8 of the 10 rabbits in each group, arterial blood samples were taken before the ischemia (T1), 30 min after the ischemia (T2) and 120 min after the reperfusion (T3) to determine the concentration of cardiac troponin I (cTnI), and the myocardial infarct area was determined at the end of reperfusion. In the other 2 of the 10 rabbits in each group,the cell ultramicro-structure injury of myocardium was examined by electron microscope at the end of reperfusion.
Results:
The concentration of cTnI at T2 and T3 in the Mor-24 group was lower than that in the NS group and Mor-12 group.The myocardial infarct size, and cell ultramicrostructure injury of myocardium in the Mor-24 group were decreased compared with the NS group and Mor-12 group.
Conclusion:
Morphine preconditioning has delayed protective effect on rabbit myocardium.
Insights
Morphine preconditioning delayed myocardial protection in rabbits. A 24-hour preconditioning significantly reduced cardiac troponin I levels and infarct size, indicating a protective effect.
Area of Science:
- Cardiology
- Pharmacology
- Cell Biology
Context:
- Myocardial ischemia-reperfusion injury remains a significant clinical challenge.
- Preconditioning strategies aim to protect the heart from ischemic damage.
- Opioids, like morphine, are being investigated for cardioprotective properties.
Purpose:
- To evaluate the delayed protective effects of morphine preconditioning on rabbit myocardium following ischemia-reperfusion.
- To determine the optimal timing for morphine administration to achieve cardioprotection.
Summary:
- New Zealand white rabbits received either normal saline (NS) or morphine (3 mg/kg).
- Groups were subjected to 30 minutes of left anterior descending coronary artery occlusion followed by 120 minutes of reperfusion at either 12 or 24 hours post-infusion.
- Cardiac troponin I (cTnI) levels, myocardial infarct size, and ultrastructural injury were assessed.
Impact:
- Morphine preconditioning administered 24 hours prior to ischemia demonstrated a significant delayed protective effect.
- Reduced cTnI concentrations and smaller infarct sizes were observed in the 24-hour morphine group.
- These findings suggest a potential therapeutic window for opioid-mediated cardioprotection.
