Reduced smooth muscle cell regeneration in Yoshida (YOS) spontaneously hypercholesterolemic rats.

Hypercholesterolemia is a predisposing factor for atherosclerosis. We studied the response to damage of vascular smooth muscle cells (SMC) from normocholesterolemic Brown Norway (BN) and from spontaneously hyper-cholesterolemic Yoshida (YOS) rats (16-24 month old). The regrowth rate of SMC from BN and YOS rats after freeze-induced damage was similar in the presence of fetal calf serum and of serum derived from normocholesterolemic rats, while it was reduced in the presence of serum from hypercholesterolemic rats. Freeze-injury of the abdominal aorta was followed by reduced neointima formation in YOS rats, as compared to BN rats, confirming the impaired response of vascular cells from hypercholesterolemic rats to injury. This defect may be due either to lipids or to unknown factors present in the hyperlypidemic serum.