β射线对血管内皮细胞的影响

目的　探讨血管再狭窄防治中 β射线对血管内皮细胞的影响。 方法　培养人脐静脉内皮细胞接受 β射线照射 2 5 ,5 0 ,10和 2 0Gy后 ,以MTT比色法分析细胞增殖反应 ,采用透射电镜进行超微结构观察和使用流式细胞仪进行DNA倍体分析以及凋亡率分析。结果　经 2 5 ,5 0 ,10和2 0Gy照射后 ,血管内皮细胞的生长呈剂量依赖性抑制 ,与对照组比较抑制率分别为 5 % (P <0 0 1)、5 % (P <0 0 1)、7% (P <0 0 1)、11% (P <0 0 1) ;透射电镜未发现典型的凋亡征象 ;流式细胞仪检查未发现DNA降解的凋亡峰 ,各实验组和对照组的凋亡率均 <4 4 % ,差异无显著性 ;DNA倍体分析发现对照组G2 /M期细胞数百分率为 13% ,各照射组依次为 17% (P <0 0 1)、2 4 % (P <0 0 1)、2 9%(P <0 0 1)、32 % (P <0 0 1) ,差异有非常显著性。G0 /G1 期对照组为 76 % ,各照射组依次为 74 %(P <0 0 5 )、70 % (P <0 0 1)、6 4 % (P <0 0 1)、6 2 % (P <0 0 1)。S期对照组为 11% ,各剂量组依次为9% (P >0 0 5 )、6 % (P <0 0 1)、7% (P <0 0 1)、5 % (P <0 0 1)。结论　 2 5 ,5 0 ,10和 2 0Gyβ射线照射后 ,内皮细胞的生长呈剂量依赖性抑制 ,细胞周期阻滞明显 ,但对内皮细胞凋亡无显著影响。

Effects of beta-rays on vascular endothelial cells

Objective To elucidate the effects of beta-rays on vascular endothelial cells in the prophylactic treatment of vascular restenosis. Methods Cultured human umbilical vein endothelial cells (HUVEC) were irradiated with 2.5,5.0,10 and 20 Gy 32P beta-rays, separately. The proliferation of the cells was determined using MTT colorimetric assay. The ultrastructural features of HUVEC were observed by transmission electron microscopy. The cell cycle progression and apoptosis of HUVEC were analyzed by flow cytometry with a FACScan model. Results HUVEC proliferation was significantly inhibited in dose-dependent manner after 2.5,5.0,10, and 20 Gy beta-rays irradiation;the inhibitory rates were 5%( P <0.01),5%( P <0.01),7%( P <0.01), and 11%( P <0.01), respectively. Electron microscopy did not evidence typical apoptosis in HUVEC after 2.5,5.0,10 and 20 Gy beta-ray irraciation. No apoptotic peak corresponding to DNA degradation was noted at low or high beat-ray doses in the histogram. The apoptosis rate was less than 4.4% in all irradiated groups and control group. But, HUVEC remained in G_2/M phases after beta exposure. The percentages of G_2/M phases were 17% ( P <0.01),24%( P <0.01),29% ( P <0.01),and 32%( P <0.01), respectively, in the irradiated groups, compared with 13% in the control group. At the same time, G_0/G_1 phases were arrested. The percentages of G_0/G_1 phases were 74%( P <0.05),70%( P <0.01),64%( P <0.01), and 62%( P <0.01), respectively, in the irradiated groups, compared with 76% in the control group. With a concomitant reduction in cell cycle progression into S phases, the percentages of S phases were 9% ( P >0.05),6% ( P <0.01),7% ( P <0.01), and 5% ( P <0.01), respectively in the irradiated groups, compared with 11% in the control group. Conclusion After 2.5,5.0,10,and 20 Gy beta-ray irradiation, HUVEC proliferation is significantly inhibited in dose-dependent manner, and cell cycle is arrested in G_2/M,G_0/G_1,and S phases;however, no significant apoptosis appears in all experimental bata-ray doses.