The biological effects of 125I seeds and 60Co γ-rays on A549 and BEAS-2B cells / 中华放射医学与防护杂志

ABSTRACT

Objective To investigate the biological effects of 125I seeds and 60Co γ-rays on the non-small cell lung cancer cells A549 and the normal bronchial epithelium cells BEAS-2B.Methods A549 and BEAS-2B cells were irradiated with 125I seeds and 60Co γ-rays.The survival fraction was detected by colony formation assay.The cell cycle and cell apoptotic ratio were detected by flow cytometry.The expression of cell apoptotic related proteins was examined by western blot.Results After irradiation with different doses,the survival of A549 cells irradiated with 125I seeds was lower than that irradiated with γ-rays (t =6.06,9.42,4.90,P ＜0.05).After irradiation with 4 Gy of 125I seeds and 60Co γ-rays,the G1 phase percentages of A549 cells were 70.67％ ± 1.49％ and 59.59％ ± 0.71％ (t =10.77,P ＜ 0.05),and the apoptotic ratios of A549 cells were 18.09％ ±0.73％ and 9.81％ ±0.16％ (t =19.40,P＜ 0.05),respectively.125I seeds irradiation remarkably up-regulated the expressions of Bax and cleaved Caspase-3 proteins,down-regulated the expression of Bcl-2 proteins compared with 60Co γ-rays irradiation on A549 cells.However,the apoptotic ratio and the expressions of apoptosis-related proteins in BEAS-2B cells had little difference between two types of radiation.Conclusions The anti-proliferative effect of 125I seeds irradiation on A549 cell is more remarkably than that of 60Co γ-rays.The imbalance of Bcl-2/Bax ratio and the eventually activation of Caspase-3 proteins may play an important role in the anti-proliferative effect induced by the continuous low dose radiation of 125I-seeds.