Altered Growth Kinetics of Dermal Fibroblasts and Arterial Smooth Muscle Cells from Spontaneously Diabetic BB Rats

We cultured arterial smooth muscle cells and dermal fibroblasts from spontaneously diabetic BB rats and normoglycemic litter mate controls. Although there were no detectable differences in the morphology of cells obtained from diabetic rats, significant differences existed in growth parameters of the diabetic smooth muscle cells. These cells grew more rapidly than smooth muscle cells from normal rats (population doubling times: normal = 42.6 ± 3.2 h, diabetic = 31.8 ± 3.7 h) and attained greater densities at confluence. The growth rates of the diabetic smooth muscle cells were dependent on the initial seeding density of cells, a characteristic not observed in cells from normal rats. Although growth rates of the diabetic smooth muscle cells were increased, their plating efficiencies were reduced. Dermal fibroblasts from diabetic rats grew at the same rates as fibroblasts from control animals and the plating efficiencies of the diabetic fibroblasts were increased rather than reduced. In these studies, we have shown that vascular-derived cells from diabetic rats have growth defects not detected in dermal fibroblasts from the same animals. This emphasizes the importance of using blood vessel cells to probe the pathophysiology of diabetic vascular disease. Furthermore, our results establish the validity of using spontaneously diabetic rats as a model system for examining inherent cell defects in insulin-dependent diabetes mellitus.