Assessment of caspase-3 activity

The caspase-3 activity was assessed according to the provided instructions of caspase fluorescent assay kit specific for caspase-3 (Biovision, Mountain View, CA, USA). Briefly, the cardiomyocytes were lysed using the cell lysis buffer in the kit and centrifuged at 10,000 × g for 1 min at 4° C. The supernatant was collected. Using the bovine serum albumin as a standard, a protein sample of equal volume was reacted with the test solution at 37° C for 1.5 h. Finally, the absorbance value at was measured at a wavelength of 405 nm.