The effect of C-reactive protein deposition on myocardial area at risk with ischemia-reperfusion injury in rats

Abstract

Objective We evaluated the effect of monomeric C-reactive protein (CRP) deposition on areas at risk (AAR) of myocardium with ischemia-reperfusion injury.

Methods Myocardial ischemia-reperfusion injury model was produced by ligation of the left anterior descending coronary artery for 45minutes followed by 45minutes of reperfusion using female Sprague-Dawley rats. Tissue from non-ischemic areas, areas at risk, and infarct areas determined by Evans blue and 2,3,5-triphenyltetrazolium chloride staining was obtained from the sham group, the ischemia-reperfusion injury without CRP injection group (I/R only group), and the ischemia-reperfusion injury with CRP injection group (I/R+CRP group). We assessed the effect of CRP injection on infarct size, CRP deposition, CRP and IL-6 mRNA expression, the third component of complement (C3) immunodeposition, and mitochondrial structural remodeling with apoptosis by quantitative RT-PCR analyses, immunohistochemistry, direct immunofluorescence, electron microscopy, and TUNEL assay, respectively. All images were analyzed using an automated morphology tool.

Results The infarct area significantly increased in the I/R+CRP group than in the I/R only group. The anti CRP antibody confirmed that CRP deposition occurred in both the infarct and AAR of the I/R+CRP group. The myocardium did not exhibit CRP mRNA expression, and the CRP treatment group showed a tendency for IL-6 to increase without statistical significance. Activated C3, apoptosis, and mitochondrial destruction increased on AAR and infarct area in the I/R+CRP group.

Conclusions These results strongly suggest the active participation of the deposition of CRP on AAR in the progression of myocardial infarction following ischemia-reperfusion injury.