Imaging myocardial ischemia and reperfusion injury via Cy5.5 Annexin V

The aim of this article is to present the results of an imaging study of myocardial apoptosis induced by ischemia/reperfusion injury. Twenty nude mice were randomly divided into an experimental group, myocardial apoptosis was induced by ligation of the left anterior descending coronary artery (LAD)for 30 min. This was followed by reperfusion for 90 min. In the control group, the heart was exposed for the same length of time as in the experimental group. Cy5.5 annexin V (25μg)was injected into both sets of mice after the onset of reperfusion. At 90 min post injection, the mice were imaged. The region of interest (ROI)was obtained, and the fluorescence intensity of the ROI was quantified. The animals were sacrificed, and myocardial apoptosis was assayed by TUNEL assay. Fluorescence intensity in the ischemia/reperfusion hearts was significantly higher than that in the control group (P<0.05). In the TUNEL assay, more apoptotic cells were observed in the experimental group than in the control group, correlating with imaging results. Fluorescence imaging of Cy5.5 annexin V in a mouse model of myocardial ischemia/reperfusion can be used in vivo as a noninvasive means of detecting ischemia/reperfusion induced apoptotic cells in the heart