Inhibitory Effect of Diabetes on Proliferation of Vascular Smooth Muscle After Balloon Injury in Rat Aorta

UNLABELLED The effect of streptozotocin-induced diabetes on cell proliferation in rat aortic intima-media, as well as on local gene expression of transforming growth factor-beta1 (TGF-beta1) was studied. TGF-beta1 mRNA was measured by solution hybridization and TGF-beta1 protein by ELISA. Proliferation was measured by bromodeoxyuridine incorporation into DNA two days after balloon injury. All BrdU-labelled cells observed were smooth muscle cells. After a diabetes duration of 2 and 4 weeks, labelled cells were significantly fewer compared with controls. Circulating levels of total TGF-beta1 were lowered in rats with 2 weeks diabetes. Although the balloon injury procedure by itself stimulated the gene expression of TGF-beta1, no significant difference in TGF-beta1 mRNA content between diabetic and control rats after injury was found. IN CONCLUSION vascular smooth muscle proliferation in vivo is inhibited by the diabetic state in this model of insulin deficient diabetes and this inhibition is not related to an impaired local expression of TGF-beta1.