gax基因对血管平滑肌细胞中p21基因表达的影响

Effects of gax gene on the expression of p21 gene in vascular smooth muscle cells

目的:研究p21基因在gax基因抑制血管平滑肌细胞(VSMC)增殖中的作用。方法:以携带大鼠gax基因表达序列的复制缺陷型5型腺病毒载体(AdCMV gax)常规转染VSMC后,应用免疫细胞化学染色检测gax和p21表达的变化;应用RT PCR检测p21mRNA表达的变化;应用3H标记的胸腺嘧啶核苷(3H TdR)掺入试验观察gax基因表达增强对VSMC增殖的影响。结果:①AdCMV gax转染前,血小板衍化生长因子BB(PDGF BB)下调gax蛋白的表达,AdCMV gax转染后,无论有无PDGF BB刺激,VSMC中gax蛋白的表达均比转染前显著增高。②AdCMV gax转染使VSMC的p21表达比未转染组显著增高。③AdCMV gax转染使VSMC的3H TdR掺入量均较未转染组显著降低。结论:gax基因抑制VSMC增殖的机制与其增强p21表达有关。

Objective: To investigate the role of p21 gene in gax gene inhibiting vascular smooth muscle cells(VSMC) proliferation. Methods: The expression of gax and p21 protein was evaluated by immunocytochemical stain and p21 mRNA by reverse transcription polymerase chain reaction (RT-PCR). The effect of gax overexpression on VSMC proliferation was observed by ^(3)H-thymidine incorporation. Results: ①Before AdCMV-gax was transfected to VSMC, gax protein could be down-regulated by platelet-derived growth factor (PDGF) BB. After AdCMV-gax was transfected to VSMC, the level of gax protein expression was significantly higher than that before transfection, and no correlation with the stimulation of PDGF-BB.②After AdCMV-gax was transfected to VSMC, p21 expression was increased.③The ^(3)H-thymidine incorporation was decreased significantly in VSMC transfected with AdCMV-gax compared with that in VSMC non-transfected. Conclusion: The mechanism of gax inhibiting VSMC proliferation is concerned with the increasing expression of p21.