Myocardial Infarction Mouse Model Study

All animal studies were approved by the Institutional Animal Care and Use Committee (IACUC) of The Catholic University of Korea (Approval number: CUMC-2015-0048-04). Myocardial infarction in the rodent model was induced as we previously described [28 (link),29 (link),30 (link)]. Male BALB/c nude mouse (8-week-old, 30–40 g; Orient bio, Seongnam, Korea) anesthetized via inhalation of 2% isoflurane were intubated through the trachea with an 18 G intravenous catheter. Then, the mice were mechanically ventilated with medical-grade oxygen. After the left thoracotomy was performed, MI was induced by the left anterior descending artery’s permanent ligation. Immediately after MI induction, BM-MSC cells, HGF-eMSC cells, or a mixture (BM-MSC and HGF-eMSC) of cells were injected directly into the ischemic area. To trace the BM-MSCs within the heart tissues further, the BM-MSCs were pre-labeled with a red fluorescence dye, CM-DiI, prior to cell injection. Briefly, BM-MSCs were stained using CellTracker™ CM-DiI Dye (Invitrogen™, Carlsbad, CA, USA). BM-MSCs were incubated in the CM-DiI Dye solution (5 µg/mL) for 5 min at 37 °C, followed by additional 15 min at 4 °C. After labeling, BM-MSCs were washed with phosphate-buffered saline (PBS) and re-suspend in serum free medium for further uses.