Ultrastructural changes of vascular smooth muscle cells and resistance to vasospasm treatment in femoral arteries of an arteriosclerotic rat model.

The objective of this study was to establish an animal model of arteriosclerosis for assessing vasospasm and to investigate the relationship between arteriosclerosis and vasospasm. Twelve-week-old male Sprague-Dawley rats were fed a diet supplemented with adenine and vitamin D (adenine/vitD). Body weight, blood, and femoral artery histopathology were assessed at 2, 4, and 6 weeks. Change in the femoral artery was examined by transmission electron microscope (TEM). Vasospasm was induced by administering epinephrine extravascularly into the femoral artery and released by the treatment with lidocaine as a vasodilator. During this period, the extravascular diameter and blood flow were measured. The rats in the adenine/vitD group developed renal dysfunction, uremia, hyperphosphatemia, and elevated serum alkaline phosphatase. Histological and TEM analyses of the femoral arteries in the treated rats revealed the degeneration of elastic fibers and extensive calcification of the tunica media and intima. Vascular smooth muscles were degenerated and osteoblasts were developed, resulting in calcified arteriosclerosis. Vasospasm in arteriosclerotic arteries was detected; however, vasodilation as well as an increase in the blood flow was not observed. This study revealed the development of vasospasm in the femoral arteries of the arteriosclerotic rats and, a conventional vasodilator did not release the vasospasm.