α粒子诱发BEP2D细胞恶性转化中抗氧化能力和辐射敏感性研究

Antioxidant ability and radiosensitivity in malignant transformed human bronchial epithelial cell line BEP2D induced by α-particle irradiation

目的研究α粒子诱发人支气管上皮细胞BEP2D恶性转化中细胞的抗氧化能力和辐射敏感性变化。方法运用谷胱甘肽过氧化物酶（GPX）、过氧化氢酶（CAT）和谷胱甘肽（GSH）试剂盒分别检测永生化人支气管上皮细胞BEP2D、α粒子作用BEP2D后第21代细胞RH21和α粒子作用BEP2D细胞后形成的恶性转化细胞BERP35T-1内抗氧化酶GPX和CAT的活性以及抗氧化剂GSH的含量；四甲基偶氮唑盐比色（MTT）法检测0、30、60、90、120和150μmol／L H2O2作用BEP2D、RH21和BERP35T-1细胞96h后，细胞增殖率的差异；0、2、4和8Gy1射线照射BEP2D、RH21和BERP35T．1细胞7～9d后，用细胞克隆计数和MTT法检测细胞增殖率和存活分数的变化。结果RH21和BERP35T-1细胞中GPX酶活力均低于BEP2D细胞（t=5．75和7．65，P〈0．05）。BEP2D细胞中CAT酶活力是RH21细胞的2．64倍，是BERP35T-1细胞的5．76倍。RH21细胞中GSH含量与BEP2D细胞比较，差异无统计学意义；恶性转化细胞BERP35T-1内GSH含量则明显低于BEP2D细胞（t=7．76，P〈0．05）。与BEP2D细胞相比，60、90、120和150μmol／LH202作用后RH21细胞的增殖率降低（t=29．90—84．68，P〈0．01），30、60、90、120和150μmol／LH202作用后BERP35T-1细胞的增殖率降低（t=10．37～58．36，P〈0．01）。4和8Gy γ射线照射后，RH21细胞的增殖率和存活分数均显著低于BEP2D细胞（t=6．33—45．00，P〈0．05）；2、4和8Gy^y射线照射后，BERP35T-1细胞的增殖率和存活分数较BEP2D细胞明显降低（t=5．87—34．17，P〈0．05）。结论 α粒子诱发人支气管上皮细胞BEP2D恶性转化过程中，细胞的抗氧化能力降低、辐射敏感性增强。抗氧化系统功能减弱可能是α粒子诱发BEP2D细胞恶性转化和辐射敏感性增强的机制之一。

Objective To investigate the antioxidant ability and radiosensitivity in the malignant transformed human bronchial epithelial cell line BEP2D induced by a-particle exposure. Methods Glutathione Peroxidase （GPX）, Catalase （CAT） and Glutathione （GSH） assay kits were employed to detect GPX and CAT enzyme abilities and the levels of GSH in BEP2D, RH21 （ passage 21 of c^-particle-irradiated BEP2D cells）, and BERP35T-1 cells （derived from nude mice bearing malignant transformed cells generated from cells of passage 35 of α-particle-irradiated BEP2D cells）. MTT assay were used to test the growth rate of BEP2D, RH21 and BERP35T-1 cells treated with 0, 30, 60, 90, 120, and 150 μmol/L H202. Colony-forming test and MTT assay were used to examine the cell survival fraction and the growth rate of BEP2D, RH21 and BERP35T-1 cells exposed to 0, 2, 4, and 8 Gy of α-rays, respectively. Results GPX and CAT enzyme activities in RH21 and BERP35T-1 cells were obviously lower than in BEP2D（t = 5.75-67.92,P 〈 0. 05）. CAT enzyme activity in BE RP35T-1 was lower than that in RH21 cells （t = 22.25 ,P 〈 0.01 ）. Compared to BEP2D cells, decreased level of GSH was detected in BERP35T-1 cells（t =7.76,P 〈0. 05） , but there was no change in RH21. After treatment with 30, 60,90, 120, and 150 ixmol/L H202, the growth rates of BEP2D were all higher than those of BERP35T-1 cells（t = 10. 37-58.36,P 〈 0.01 ）. Meanwhile, the growth rates of BEP2D were all higher than those of RH21 cells after treatment with 60, 90, 120, and 150 txmol/L H202 （ t = 29.90-84.68,P 〈 0.01 ）. In addition, compared to BEP2D cells, decreased cell survival fraction and growth rate of BERP35T-1 cells were observed after irradiation with 2, 4, and 8 Gy of α-rays（ t = 5.87-34.17 ,P 〈 0. 05 ）. The cell survival fraction and growth rate of RH21 were all lower than those of BEP2D cells at 4 and 8 Gy post-irradition（ t = 6. 33- 45.00,P 〈 0. 05 ）. Conclusion The function of antioxidant system decreased in the a-particle- induced transformed cells, which could contribute to the acceleration of cellular malignant transforming process and radiosensitivity.