| Objective To evaluate the effect of low dose rate and continuous irradiations with Iodine-125 seeds on proliferation,cell cycle distribution,apoptosis to HepG2 cell line. To study the mechanism of radioactive Iodine-125 seeds interstitial brachytherapy in the treatment of hepatocellular carcinoma.Methods The irradiator consisted of nine Model 6711 iodine-125 seeds, each with 29.6MBq of apparent activity. Eight seeds were equally spaced around the circumference of a 3cm diameter circle and the ninth seed was confined to the center. Hepatoma Carcinoma Cells HepG2 were placed 5mm above the seed plane and delivered dose of 200cGy(at initial dose rate of 5.32cGy/h).Expressions of apoptosis genes Bcl-2 and Bax were detected by immunohistochemical mehtods, respectively. Cell cycle was analyzed by flow cytometry. The rate of apoptosis was determined by Annexin V-FITC/ PI staining.Results 1.Flow cytometry showed that the G1,G2-M and S phase distribution of the irradiated cells changed from(58.78±4.41)%,(6.75±1.32)%,and(34.48±3.37)% (n=12)to(45.8±3.89)%,(13.82±2.04)%,and(40.38±2.68)% (n=12),respectively(P<0.05). Annexin V-FITC/ PI staining showed that the apoptosis rates of the control group cells(n=12) and irradiated group(n=12) were(0.83±1.04)% and (19.42±4.15)%,respectively, P<0.05.2.Immunohistochemical examination showed that the expression of Ki67 in iodine-125 seed group was"+-++++",while in control group the expression was"+++-+++++".There were significant difference between the iodine-125 seed group and the control group.(u= 6.79, 0.005 |
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