2.3. TTC Staining

Heart samples were collected after the rats were sacrificed and placed into a refrigerator (-80) for 8 min, then cut into slices with a thickness of about 2~3 mm each. Slices were immersed for 30 min into 2% triphenyltetrazolium chloride (TTC) solution at 37°C in the dark. Stained slices were fixed in 4% paraformaldehyde for 30 min. Images were taken by the FSX100 microscope (Olympus, Shenzhen, China), and sizes of different stained areas were measured with the image analysis software Image-Pro Plus 6.0. The ratios of the infarct area to the left ventricular area were calculated.