Effects of Mesenchymal Stem Cell Injection into Healed Myocardial Infarction Scar Border Zone on the Risk of Ventricular Tachycardia

Figure 1. Exposure of rabbit heart after left thoracotomy. (A) Infarcted area of left ventricle after left anterior descending coronary artery ligation procedure, and (B) scar border zone targeted for cell injections (arrows).

Figure 2. Echocardiographic results in the three groups at follow-up (4 weeks after cell injections). (A) Left ventricular EF, (B) LVEDV, and (C) LVESV. * Indicates p-value < 0.05, ** indicates p-value < 0.01, *** indicates p-value < 0.001 and “ns” indicates no significance. EF = ejection fraction; LVEDV = left ventricular end-diastolic volume; LVESV = left ventricular end-systolic volume; PBS = phosphate-buffered saline; and MSC = mesenchymal stem cell.

Figure 3. Pathologic examination of left ventricles. (A) Gross specimens showing decreased fibrotic area in the MSC group compared with the PBS group. (B) Histologic examination after Masson’s trichrome staining shows decreased fibrotic area in the MSC group compared with the PBS group. MSC = mesenchymal stem cell and PBS = phosphate-buffered saline.

Figure 4. Cx43 expression in the infarct border zone area in the three groups. (A) Confocal immunofluorescence imaging shows decreased Cx43 signals (red) in the PBS group and restoration of Cx43 expression in the MSC group. The grayscale image was obtained by deconvolving the maximum intensity DAPI image and merging with Cx43. (B) The images at 400× magnification. Cx43 = connexin 43; PBS = phosphate-buffered saline; and MSC = mesenchymal stem cell.

Figure 5. Quantitative analysis for Cx43 expression. Cx43 signal intensity in the infarct border zone was significantly higher in the MSC group than in the PBS group and was similar between the sham control and the MSC group. * Indicates p-value < 0.05 and “ns” indicates no significance. Cx43 = connexin 43; PBS = phosphate-buffered saline; and MSC = mesenchymal stem cell.