Hepes buffered saline

Cardiomyocyte isolation was performed on mice. The extracted myocardial tissue was cut into small pieces and transferred to 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES)-buffered saline (Gibco, USA) containing 0.1% type IV collagenase (Gibco, USA), 0.1% trypsin (Gibco, USA), and 15 µg/mL DNase I at 37 ℃. After centrifugation, the lysed cells were resuspended in Dulbecco’s modified Eagle’s medium (DMEM; Gibco, USA) with nutrients and then inoculated on collagen-coated silica sheets in preparation for extraction of cardiomyocytes. After 24 hours post inoculation, the original culture medium was replaced with serum-free medium and the culture was continued for 24 hours. All cells used in the experiments were pre-treated with PE. Lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD) and creatine kinase (CK) assay kits were purchased from Nanjing Jiancheng Biological Engineering Research Institute, all tests are performed according to kit instructions.

Centricon filters were purchased from Amicon (Beverly, MA). Super Blue TMB Microwell Substrate was a product of KPL (Gaithersburg, MD). Microwell plates for ELISA (high-binding, flat bottom) and standard tissue culture plastic were purchased from Corning/Costar (Cambridge, MA). Ultralink Bio-support beads (50–80 µm diameters) for equilibrium binding studies were purchased from SapidyneInc (Boise, ID). Horseradish peroxidase-labeled goat anti-human IgG were purchased from Jackson ImmunoResearch Laboratories (Catalog; AB_2337577, West Grove, PA). Fetal bovine serum (FBS) (low IgG) was from Hyclone Laboratories (Logan, UT). HEPES-buffered saline (HBS, 137 mM NaCl, 3 mM KCl, 10 mM HEPES, pH 7.4) was prepared using reagents from Fisher Scientific (Pittsburgh, PA). L-glutamine (Catalog; 25030149), Penicillin-Streptomycin (Catalog; 15140122) from Fisher Scientific, Pittsburgh, PA), and bovine serum albumin (BSA) (fraction V, metal-free (Catalog; 10735094001) from Sigma Aldrich Inc St. Louis, MO 68178.