摘要目的 探讨Rac1活化在血小板衍生生长因子(PDGF-BB)刺激引起的大鼠主动脉平滑肌细胞增殖与迁移中的作用.方法 贴块法分离培养主动脉平滑肌细胞,CCK8法和Transwell小室检测Rac1抑制剂NSC23766和Rac1siRNA对PDGF-BB诱导的平滑肌细胞增殖和迁移的影响.GST-pulldown法和免疫印迹(Western印迹)检测PDGF-BB对Rac1活性和pi-JNK表达的时间特性以及NSC23766和Rac1 siRNA对Rac1活性和pi-JNK表达的影响.结果 PDGF-BB(50 μg/L)显著促进了大鼠主动脉平滑肌细胞的增殖和迁移.在给予不同浓度NSC23766( 25、50、100 μg/L)以及Rac1 siRNA( 50 nmol/L)后,其增殖和迁移显著受到了抑制.PDGF-BB刺激后Rac1活性和pi-JNK逐渐升高,并分别在5 min和15 min达到最高峰后下降.给予NSC23766和Rac1 siRNA处理后Rac1活性(5 min)和pi-JNK( 15 min)表达均明显受到了抑制.结论 Rac1活性影响JNK磷酸化并在调节PDGF-BB诱导的主动脉平滑肌细胞增殖与迁移中起着重要的作用.

abstractsObjective To explore the impact of Rac1 activation on the proliferation and migration under the stimulation of PDGF-BB ( platelet derived growth factor-BB).Methods The inhibitory effects of Rac1 inhibitor (NSC23766) and Rac1siRNA on the proliferation and migration of vascular smooth muscle cell under the stimulation of PDGF-BB were measured by CCK8 assay and Transwell chamber.The time characteristics of Racl activity and pi-JNK expression under the stimulation of PDGF-BB was detected by GST pulldown assay and Western blot.And the inhibitory effects of NSC23766 and RaclsiRNA on the Rac1 activation and pi-JNK expression were also measured.Results Migration and proliferation of vascular smooth muscle cell increased significantly after the stimulation of PDGF-BB ( 50 μg/L).Migration and proliferation was inhibited significantly after a pretreatment of RaclsiRNA and various concentrations of NSC23766(25,50,100 μg/L).After the stimulation of PDGF-BB,the expression of pi-JNK and Rac1 activity increased over time.Rac1-GTP peaked at 5 minutes and pi-JNK at 15 minute.The expressions of piJNK at 15 minutes and Rac1-GTP at 5 minutes were inhibited significantly by Rac1siRNA and NSC23766 in a concentration-dependent manner.Conclusion JNK phosphorylation is controlled by Racl activation.And Rac1 activation play a pivotal role in the migration and proliferation of aortic smooth muscle cell under the stimulation of PDGF-BB.