[Ultrastructural and immunohistochemical study of experimental atherosclerosis in Japanese quails]

A marked plaque was produced at the tunica intima of the ascending aorta in all of the Japanese quails of 9 weeks old which fed on atherogenic diet containing 2% cholesterol for 8 weeks, while no structural changes of aortic wall were observed in Japanese quails which fed on normal basic food for the same period. The media of aorta in normal quails consist of smooth muscle cells, myofibroblast-like cells (MF) cells), and many successive elastic membranes. At the atherosclerotic lesion, many MF cells migrated from media into intima, and a part of smooth muscle cells were also differentiated to MF cells. Moreover, the most migrating MF cells differentiated to foam cells at the intimal thickness regions, and a few other MF cells also differentiated into endothelial cells of newly forming capillaries. By the immunohistochemical stainings, medial smooth muscle cells were negatively stained with anti-vimentin antibody, and the majority of cells in the intima (MF cells, foam cells, and endothelial cells) contained vimentin filaments. These results indicate that MF cells play a very important role in the development of atherosclerosis in Japanese quail. The morphologicals study offers some new insights into the evaluation of Japanese quails as an animal model of atherosclerosis.