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Updated: Mar 16, 2026
A Murine Closed-chest Model of Myocardial Ischemia and Reperfusion
Published on: July 17, 2012
Defining the sham environment for post-myocardial infarction studies in mice
Rugmani Padmanabhan Iyer1, Lisandra E de Castro Brás2, Presley L Cannon1
1Mississippi Center for Heart Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi;
Abstract:
The purpose of this study was to evaluate the effect of sham surgery in a minimally invasive surgical model of permanent coronary artery occlusion used to generate myocardial infarction (MI) in mice. Adult male C57BL/6J mice (3-6 mo old) were divided into five groups: day (D) 0 (no surgical operation), D1 Sham, D1 MI, D7 Sham, and D7 MI. A refined MI surgery technique was used to approach the coronary artery without the ribs being cut. Both sham and MI mice had the left ventricle (LV) exposed through a small incision. To test the effects of surgery alone, the suture was passed around the coronary artery but not ligated. The MI mice were subjected to permanent coronary artery ligation. The mice were killed at D1 or D7 postsurgical procedure. Compared with D0 no surgery controls, the D1 and D7 sham groups exhibited no surgical mortality and similar necropsy and echocardiographic variables. Surgery alone did not induce an inflammatory cell response, as evidenced by the lack of leukocyte infiltration in the sham groups. Analysis of 165 inflammatory cytokines and extracellular matrix factors in sham revealed that a minor gene response was initiated but not translated to protein levels. Collagen deposition did not occur in the absence of MI. In contrast, the D1 and D7 MI groups showed the expected robust inflammatory and scar formation responses. When a minimally invasive procedure to generate MI in mice was used, the D0 (no surgical operation) control was an adequate replacement for the use of sham surgery groups.
Insights
For mouse models of myocardial infarction (MI), a no-surgery control effectively replaces sham surgery. This minimally invasive technique avoids unnecessary procedures, simplifying research on heart attack models.
Area of Science:
- Cardiovascular Research
- Surgical Models
- Myocardial Infarction Research
Background:
- Sham surgeries are traditionally used as controls in surgical models.
- Minimally invasive techniques for inducing myocardial infarction (MI) in mice require appropriate control groups.
- Evaluating the necessity of sham procedures in these models is crucial for research efficiency.
Purpose of the Study:
- To assess the efficacy of sham surgery as a control in a minimally invasive mouse model of coronary artery occlusion.
- To determine if a no-surgery control group is a suitable alternative to sham surgery for MI studies.
Main Methods:
- Adult male C57BL/6J mice underwent a refined, minimally invasive surgery for coronary artery ligation (MI) or sham procedure.
- Groups included: no surgery (D0), sham surgery (D1, D7), and MI (D1, D7).
- Evaluations included mortality, necropsy, echocardiography, leukocyte infiltration, inflammatory cytokine/ECM factor analysis, and collagen deposition.
Main Results:
- Sham surgery groups showed no mortality and comparable necropsy/echocardiographic results to the no-surgery control.
- Sham groups lacked significant inflammatory cell infiltration and protein-level gene responses; no collagen deposition occurred.
- MI groups exhibited expected inflammatory and scar formation responses, confirming model validity.
Conclusions:
- In this minimally invasive MI mouse model, a no-surgery control group adequately replaces sham surgery.
- Sham procedures in this specific model do not induce significant physiological changes or inflammatory responses.
- Utilizing a no-surgery control simplifies the experimental design and reduces animal use in MI research.
