Study Objective - 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. Method and Results - Adult male C57BL/6J mice (3-6 months old) were divided into 5 groups: day (D) 0 (no MI), 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 sacrificed at D1 or D7 post-surgical procedure. Compared to D0 controls, the D1 and D7 sham groups exhibited no surgical mortality and similar necropsy and echocardiographic variables. Surgery alone did not induce an inflammatory response, as evidenced by the lack of leukocyte infiltration in the sham groups. Gene array analysis for 165 inflammatory cytokine and extracellular matrix genes revealed only minor changes in the sham groups that did not translate to protein differences. 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. Conclusion - When using a minimally invasive procedure to generate MI in mice, the D0 no MI control is an adequate replacement for the use of sham surgery groups.
- myocardial infarction
- permanent occlusion
- LV remodeling
- Copyright © 2016, American Journal of Physiology-Heart and Circulatory Physiology