Histopathological observations of the heart (100×). (a) Control rat heart revealed normal architecture of myocardium. (b) ISO-induced myocardial infarcts show cardiac muscle separation, necrosis with inflammatory cells. (c) RouDouKou-treated rats showed a small amount of vacuolar degeneration, and the myocardial fibers have a relatively wider gap. (d) GuangZao group showed evidence of inflammatory infiltration and relatively small gaps between myocardial fibers. (e) FCN group only showed mild separation of cardiac muscle fibers without necrosis and inflammatory cells.