Outer Balloon Ligation Increases Success Rate of Ischemia-Reperfusion Injury Model in Mice

Coronary artery disease is a growing public health problem and a major cause of morbidity and mortality. Experimental animal models provide valuable tools for studying myocardial ischemia reperfusion (I/R) injury in vivo.

The purpose of this study was to describe a new method (outer balloon ligation) to induce myocardial I/R injury in mice.

Ninety-nine male C57BL/6J mice were randomly divided into three groups: sham group, classic method group (I/R-C) and the new method group (I/R-N). The surgical procedure and recovery time were recorded. The levels of TNF-α, IL-6, cTnT and LDH were detected by ELISA kits. Hematoxylin-eosin staining was applied to assess neutrophil infiltration. Moreover, surgical survival, myocardial infarction areas, and cardiac function measurements were also recorded.

The reperfusion operation time in the I/R-N group were markedly less than the I/R-C group (14.73±2.86 vs. 168.60±33.01 sec, p <0.0001). Similarly, the recovery time in I/R-N group was shorter than the I/R-C group (45.39±15.39 vs. 101.70±19.33 min, p <0.0001). The levels of TNF-α and IL-6 in I/R-N group were also markedly lower than in I/R-C group (136.5±22.21 vs. 170.5±24.79 pg/ml, p <0.05 and 100.3±23.74 vs. 144.40±22.24 pg/ml, p <0.001). Compared I/R-N group with I/R-C group, the levels of neutrophil infiltration, cTnT and LDH had no significant differences. Surgical survival rate was 96.7% in the I/R-N group, which was significantly improved compared to the rate of 80% in the I/R-C group. However, there were no significant differences in the areas of myocardial infarction and cardiac function between the two groups.

Compared with the classic method, our new method of inducing myocardial I/R injury has higher efficiency and less tissue damage in mice, but achieves the same modeling effects.