| Summary: | 碩士 === 國立臺灣大學 === 獸醫學研究所 === 95 === Cardiovascular disease is very important in clinic, and the detection of the change of mechanical properties of vessel wall is helpful for early diagnosis of cardiovascular disease. The ultrasonic examination of mechanical properties of vessel wall include intima-media thickness (IMT), stiffness, and energy dissipation ratio (EDR). In this study, the mechanical properties of arterial wall were examined with ultrasonography, and images data were analyzed by vascular index (VI) software which was developed by Biomedical Ultrasound Laboratory in the Institute of Applied Mechanics. After the dogs were anesthetized, the brachial artery, radial artery, femoral artery, tibial artery, and common carotid artery were examined by ultrasonography. The experiments included: (1) comparison of the arterial mechanical property among the dogs with different ages; (2) detection of the change of arterial mechanical property when blood pressure increased; (3) examination of the change of mechanical property on a regular time schedule after the brachial arteries were damaged by angioplasty. All damaged vessels were collected for histo-pathological study and compared with the result from ultrasonographic study. The values of IMT and arterial stiffness increased when animal getting old. The values of EDR decreased following with the increase of age. The IMT, arterial stiffness, and EDR increased when blood pressure elevated. Following the damage of brachial artery, the value of IMT increased continuously. The value of arterial stiffness and EDR increased at 1st~4th weeks, and then decreased at 8th~12th weeks. However the value of arterial stiffness and EDR increased again at 20th week. From the histo-pathological study, the thickening of intima and media of the damaged vessels could be observed. The increase of the collagen fibers could be observed with Trichrome stain. The birefringence of thick and thin collagen fibers could be observed simultaneously in the intimal lesion with Picro-sirius polarization. The proliferation and migration of smooth muscle cell in the intima was identified with α-smooth muscle actin immunochemical stain. The results of the study indicate that the changes of IMT, stiffness and EDR of the vessel wall are related with the increase of collagen fiber and the proliferation and migration of smooth muscle cell.
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