Effect of insulin on phenotypic transition of rat vascular smooth muscle cells in vitro

Objective:To investigate the effects of insulin on phenotypic transition of vascular smooth muscle cells (VSMCs) in Wistar rats. Methods: VSMCs were enzymatically isolated from aorta of Wistar rats, and their growth characteristics were evaluated by [3H] thymidine incorporation,α-smooth muscle(α-SM) actin by immunocytochemical staining; mRNA expressions of phenotype markers and growth factors were detected by reverse transcription polymerase chain reaction analysis j F-actin and G-actin display by fluorescence of molecular probes in VSMCs. Results: VSMCs of insulin group showed increasing basal DNA synthesis and higher responses of DNA synthesis (47% ,P0. 01). Immunocytochemical staining of VSMCs a-SM actin in insulin group was weaker than those in control group. Expressions of phenotype markers mRNA, such as matrix Gla and OPN, were greater in VSMCs of insulin group than in those of control group(P0. 05). Expressions of transforming growth factor-β, platelet-derived growth factor and basic fibroblast growth factor in insulin group were also greater than those of control group(P0. 05). The display of F-actin and G-actin in VSMCs was remarkably different between the insulin group and control group. Conclusion: The results of this study demonstrate a positive effect of insulin on phenotypic transition in VSMCs of Wistar rats.