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

Background 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. Objective The purpose of this study was to describe a new method (outer balloon ligation) to induce myocardial I/R injury in mice. Methods 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-alpha, 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. Results 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-a 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. Conclusions 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.