胰岛素对大鼠血管平滑肌细胞表型转化的影响

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

目的:探讨胰岛素对体外培养的血管平滑肌细胞(vascular smooth muscle cell,VSMC)表型转化的影响。方法:用酶消化法分离大鼠VSMC,采用免疫组织化学法检测胰岛素作用后VSMC肌动蛋白(α-SM actin),RT-PCR检测胰岛素作用后VSMC中bFGF、TGF-β、PDGF、matrix Gla和OPN各目的基因mRNA相对表达水平。结果:胰岛素组VSMC的3H-TdR掺入值比对照组升高47％(P<0.01),VSMC α-SM actin免疫组化结果显示对照组的α-SM actin比胰岛素组染色深。而matrixGla和OPN在培养的VSMC中mRNA的表达量,胰岛素组明显高于对照组(P<0.05),同时bFGF、TGF-β、PDGF的表达胰岛素组也明显高于对照组(P<0.05)。并可明显见到细胞骨架F-actin、G-actin重新分布。结论:在合成表型的matrix Gla和OPN表达量明显高于收缩表型,而合成表型的α-SM actin表达量明显低于收缩表型。提示胰岛素对VSMC的表型转化起了一定作用。胰岛素在促进了VSMC增殖的同时,伴有VSMC由收缩型转变为合成型及细胞骨架F-actin、G-actin重新分布。

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% ,P<0. 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(P<0. 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(P<0. 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.