Figure 5: Scanning electron microscope (SEM) observation of inner walls of thoracic aortas (×500). (a) Con; (b) Met; (c) OVX + Met; (d) OVX + Met + GST. The tunica intima was smooth and intact with flat endothelial cells in both Con and Met group. In OVX + Met, the impairment of endothelial cells was very serious with some endothelial cells atrophy, deformed, desquamation, and some fibrin adherent to the endothelium surface. In OVX + Met + GST, the endothelium damage was slight with tunica intima almost intact.