Objective: To investigate the effects of millimeter wave (MMW) exposure on apoptosis of human melanoma A375 cells and explore the mechanisms.
Methods: Through electromagnetic field calculation we simulated MMW exposure in cells and calculated the specific absorption rate (SAR). The optimal irradiation parameters were determined according to the uniformity and intensity of the SAR. A375 cells were then exposed to MMV for 15, 30, 60, or 90 min, with or without pretreatment with the caspase-3 inhibitor AC-DEVD-fmk (10 μmol/L) for 1 h at 90 min before the exposure. CCK-8 assay was used to assess the changes in the viability and Annexin-V/ PI staining was used to detect the apoptosis of the cells following the exposures; Western blotting was used to detect the expression of caspase-3 in the cells.
Results: The results of electromagnetic field calculation showed that for optimal MMV exposure, the incident field needed to be perpendicular to the bottom of the plastic Petri dish with the antenna placed below the dish. CCk-8 assay showed that MMW exposure significantly inhibited the cell viability in a time-dependent manner (P < 0.05); exposures for 15, 30, 60, and 90 min all resulted in significantly increased apoptosis of the cells (P < 0.05). The cells with MMW exposure showed significantly increased expression of caspase-3. The inhibitory effect of MMW on the cell viability was antagonized significantly by pretreatment of the cells with AC-DEVD-fmk (P < 0.05), which increased the cell viability rate from (36.7±0.09)% to (59.8±0.06)% (P < 0.05).
Conclusions: 35.2 GHz millimeter wave irradiation induces apoptosis in A375 cells by activating the caspase-3 protein.
目的: 研究毫米波电磁场辐照对人黑素瘤A375细胞凋亡的影响。
方法: 研究共分为两部分：电磁场计算实验和细胞实验。电磁场计算实验通过模拟毫米波辐照细胞这一生物物理过程，计算并对比分析比吸收率（SAR）的均匀性及强度，得出最佳辐照参数。细胞实验中，A375细胞以35.2 GHz毫米波分别辐照15、30、60、90 min，非辐照组除不接受辐照外其他环境与辐照组保持一致，caspase-3抑制剂（AC-DEVD-fmk）组在毫米波辐照90 min前以10 μmoL的AC-DEVD-fmk预处理1 h。用CCK-8法检测辐照组，非辐照组及AC-DEVD-fmk预处理组的细胞活性。用Annexin-V/ PI双染法检测细胞凋亡情况，蛋白印迹法检测细胞内凋亡蛋白caspase-3的表达水平。
结果: 电磁计算得出的最佳辐照方式为沿天线线极化方向，入射场垂直于塑料培养皿底部，自下而上辐照。CCK-8细胞活性检测法的结果表明，毫米波对A375细胞活性具有抑制作用（P < 0.05），且呈时间依赖性。与非辐照组相比，15、30、60、90 min毫米波辐照组A375细胞的凋亡率显著升高（P < 0.05）。辐照组A375细胞中caspase-3表达水平明显增加，应用caspase-3抑制剂后可以逆转毫米波辐照对细胞活性的抑制作用，细胞活性率由（36.7±0.09）%增加到（59.8± 0.06）%，与对照组相比差异具有统计学意义（P < 0.05）。
结论: 35.2 GHz毫米波辐照可以通过激活caspase-3诱导A375细胞凋亡。
Keywords: apoptosis; electromagnetic calculation; irradiation; specific absorption rate.