For the histopathology analyses, mice were euthanized with 100 μL of a 10 : 1 mixture of ketamine (90–120 mg/kg) and xylazine (10 mg/kg), respectively. The thoracic cavity was opened, and the heart was removed 24 hours after surgery (n = 6 animals/group SSI/SSI+VP and n = 4 animals/group sham/SH+VP). Hearts were longitudinally sectioned into two halves; one-half of the heart was fixed in phosphate-buffered 10% formalin and embedded in Historesin (Leica Instruments, Heidelberg, Germany) for high-resolution light microscopy. The 2 μm thick sections were stained with toluidine blue, and left ventricles were analyzed. Another half of the hearts were frozen at -80°C for the immunoblotting procedure.