Résumé
Objective To investigate the mechanism of extremely low frequency electromagnetic field (ELF-EMF) and X-ray irradiation on liver carcinoma cell lines BEL-7402. Methods Liver carcinoma cell lines BEL-7402 had been incubated with ELF-EMF (100 Hz, 0.7 mT, 30 min, 3 days) after X-ray irradiation at different doses (0, 2, 4, 6, 8,10 Gy). The cells were observed on morphologic changes with scanning electron microscope. Flow cytometry and gene microarray were used to investigate the mechanism of cell apeptosis. Results ELF-EMF plus X-ray induced apoptosis on BEL-7402 was observed under scanning electron microscope.When X-irradiation was 2, 4, 6, 8 and 10 Gy, the apoptosis ratios of combined group and only X-irradiation group were 10.0%, 14.5%, 4.3%, 5.1%, 7.1% and 0.1%, 8.1%, 0.1%, 0.4%, 2.2% (P < 0.05) on flow cytometry. The result of microarray indicated that 1465 genes were up-regulated and 1108 down*regulated in the ELF-EMF plus X-ray group in comparison with the control group. The change rates of 110 apoptosis related genes were above 2 times, which including 71 up-regulated and 39 down-regulated. Gene microarray showed that ELF-EMF and X-ray irradiation had a mainly effect on different gene of apoptosis paths (CDC25 and CHKI, ATM, p38, PTEN, p53, G1/S, Fas, G2/M, Cell Cycle, Apoptosis and Caspase). The same genes of ELF-EMF plus X-ray group were showed 13 in ELF-EMF group and 42 in X-ray group. Conclusions Apoptosis paths were significantly different between ELF-EMF and X-irradiation. ELF-EMF cooperates with X-irradiation on inducing BEL-7402 cell apoptosis.