Animals were anesthetized with inhalational isoflurane in 100% O2 (5.0% induction; 2.5% maintenance). Endotracheal intubation was performed and the animals ventilated with positive-pressure ventilation. A left lateral thoracotomy was performed. The pericardial sac was identified and a small portion opened sharply exposing the left ventricle at the intended LAD ligation site. For animals that underwent MI, the LAD was identified and ligated with a 7–0 poly-propylene suture (Ethicon, Somerville, New Jersey) 1–2 mm from its origin.28 (link) Visual confirmation of infarction was noted by edema and discoloration of the anterior LV wall. MSC or blank cell capsules were then deposited on a sterile surgical towel and then deposited in the pericardial space on the epicardial surface of the right and left ventricle with surgical forceps. For each animal 1.5mL of capsules were deposited. For animals in the MSC injection group, 0.2 cc (4×106 cells per rat) were injected into the left ventricle myocardium in the infarct zone using a 27 gauge syringe. Cells were injected obliquely and the needle was not withdrawn for 10 seconds to minimize chance for cell leakage. The chest was then sutured closed in layers and the animals were extubated and allowed to recover.