Biological Features In Vitro

Abstract Endothelial denudation by balloon injury of the rat aorta induces the development of a neointima as a conse-quence of the migration and proliferation of smooth muscle cells (SMCs). Initially, intimal SMCs show a dedifferentiated phenotype, which reverts to a normal differentiated phenotype after endothelial cells have resurfaced the vessel lumen. We investigated in vitro the proliferative and phenotypic features of SMCs from different layers of rat aorta isolated 15 and 60 days after endothelial denudation. Freshly isolated intimal cells 15 days after balloon injury (IT-15) appeared rounded and showed a decreased content of a-smooth muscle actin, smooth muscle myosin, and desmin compared with intimal cells isolated 60 days after balloon injury (IT-60). No morpho-logical and cytoskeletal differences were observed among freshly isolated IT-60 cells and other medial populations