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目的 探讨X射线对血管平滑肌细胞抑制作用的信号传导机制。方法 建立体外培养的大鼠血管平滑肌细胞 (VSMC)模型 ,给予 2～ 2 0Gy(分别为 2、5、10、15、2 0Gy)单次X射线照射 ,采用逆转录—聚合酶链反应 (RT PCR)技术 ,在mRNA水平观察X射线对VSMC粘着斑激酶 (FAK)的影响。结果 2～ 2 0Gy单次X射线照射下调FAKmRNA表达。照射后 48h ,2、5、10、15、2 0Gy各照射组FAKmRNA表达均明显低于对照组 ,除 2 0Gy与 15Gy剂量组之间差异无显著性意义外 ,各组FAKmR NA表达差异均有极显著性意义 (F =36 4.2 1,P <0 .0 1)。同一剂量 15Gy照射后 6、2 4、48、72h照射组FAKmRNA表达均低于同时间点对照组 ,差异有显著性意义 (分别为t=4.0 7,P =0 .0 1;t=7.48,P =0 .0 2 ;t=9.10 ,P =0 .0 0 ;t=12 .93,P =0 .0 0 ) ,照射后 45min、12h两组FAKmRNA表达差异无显著性意义 (分别为t=2 .18,P =0 .10 ;t=1.46 ,P =0 .2 2 )。结论 放射可能通过在转录水平下调FAK的基因表达 ,使VSMC增殖受到抑制 ,诱导VSMC凋亡。其下调作用呈剂量相关性和时间相关性。
Objective To investigate the signal transduction mechanism of X-ray inhibition on vascular smooth muscle cells. Methods Rat vascular smooth muscle cells (VSMCs) were cultured in vitro and were irradiated with 2 ~ 20 Gy (2, 5, 10, 15 and 20 Gy, respectively). RT - PCR PCR) technique was used to observe the effect of X-rays on focal adhesion kinase (FAK) in VSMCs at mRNA level. Results 2 ~ 20 Gy single X-ray irradiation reduced FAK mRNA expression. At 48h after irradiation, the expression of FAKmRNA in each irradiation group was significantly lower than that in the control group except for 2 0Gy and 15Gy dose groups Very significant (F = 36 4.2 1, P <0.01). The same dose of 15Gy irradiation 6,2 4,48,72 h irradiation FAKmRNA expression were lower than the same time point control group, the difference was significant (t = 4.07, P = 0.01; t = 7.48, There was no significant difference in the expression of FAK mRNA between the two groups at 45 min and 12 h after irradiation (t = 9.10, P = 0.00; t = 12.93, P = = 2.18, P = 0.10; t = 1.46, P = 0.2 2). Conclusion Radiation may inhibit the proliferation of VSMC and induce the apoptosis of VSMC by down-regulating the gene expression of FAK at the transcriptional level. The down-regulation was dose-related and time-dependent.