胰岛素对SHR血管平滑肌细胞增殖和表型转化的MAPK机制的研究

Study of MAPK on effect of insulin on proliferation of vascular smooth muscle in SHR rats

目的探讨胰岛素对自发性高血压大鼠(spontaneously hypertensive rat,SHR)血管平滑肌细胞(VSMC)增殖和表型转化的影响及其机制。方法分离、培养SHR大鼠的VSMC,各分对照组、胰岛素组,用MAPK抑制剂PD98059预处理SHR大鼠体外培养的血管平滑肌细胞。观察PD98059预处理后SHR血管平滑肌细胞的增殖率和迁移率以及细胞内DNA的合成情况。同时采用免疫印迹检测MAPK的表达,免疫组化检测VSMC肌动蛋白(-αSM actin)。结果SHR胰岛素组的VSMC[3H]-TDR掺入值(counts/min)10.38±0.82高于PD98059预处理组的VSMC[3H]-TDR(counts/min)6.34±0.51。胰岛素组VSMC的迁移率是PD98059预处理组的4.04倍(P<0.01)。胰岛素组MAPK的表达明显比对照组高。免疫组化结果显示PD98059预处理组a-SM actin比胰岛素组染色深。结论胰岛素促进SHRVSMC增殖及表型转化,这种作用可被MAPK抑制剂阻断,提示MAPK参与了胰岛素的这种作用。

Objective To study the effects and mechanism of insulin on proliferation and phenotypic transition of vascular smooth muscle cells（VSMCs） in spontaneously hypertensive rat（SHR）. Methods VSMCs were enzymatically isolated from SHR and pretreated with insulin and/or PD98059. Their growth characteristics were evaluated by [^3 H]-thymidine incorporation： a-SM actin by immunocytochemical staining;MAPK by western-blot. Proliferation and migrationg of VSMCs were also observed. Results [^3H]-thymidine incorporation in VSMCs from insulin group （10. 38±0. 82） was higher than that in VSMCs from PD98059 group（6.34±0.51,P〈0.05）. Migration rate and proliferation rate of VSMCs from insulin group were about 4.04 times higher than VSMCs from PD98059 group （P〈0.05）. hnmunocytochemical staining of VSMCs revealed that α-SM actin in insulin group was weaker than in PD98059 group. Conclusion The study demonstrates a positive effects of insulin on proliferation and phenotypic transition in VSMCs of SHR,and MAPK may be involved in these.