长期工频电磁场暴露对SRA01／04细胞增殖和凋亡的影响

Effect of long-term power frequency electromagnetic field exposure on proliferation and apoptosis of SRA01/04 cells

目的探讨50Hz工频电磁场长期暴露对人眼晶状体上皮细胞（SRA01／04）增殖和凋亡的影响。方法将处于对数生长期的SRA01~4细胞暴露或假暴露于频率为50Hz、磁场强度为2．3mT的工频电磁场中，每天2h，每周5d，连续暴露11周。暴露结束后立即收集细胞，显微镜下观察细胞形态变化，噻唑蓝（MTT）法检测细胞存活力，流式细胞仪（FCM）检测细胞周期和凋亡情况，免疫印迹（Western blot）法检测周期素D（Cyclin-D）与增殖细胞核抗原（PCNA）蛋白表达量的变化。结果与假暴露组相比，暴露组大部分细胞形状变为圆形，立体感增强，部分细胞可见异染色质边集；MTT法检测结果显示，暴露组细胞存活力明显增强，与假暴露组相比，差异有统计学意义（P〈0．05）。细胞周期检测结果显示，暴露组处于S期的细胞数量明显高于假暴露组，差异有统计学意义（P〈O．05），细胞增殖指数（PI）主要数据大于假暴露组主要数据，差异亦有统计学意义（P〈0．05）；假暴露组细胞凋亡与暴露组相比，差异无统计学意义（P〉0．05）；暴露组细胞Cyclin-D与PCNA的蛋白表达水平较假暴露组细胞明显增加，差异有统计学意义（P〈0．05）。结论长期工频电磁场暴露可促进SRA01／04细胞的增殖，改变细胞周期进程，但对细胞凋亡没有明显影响。

Objective To investigate the effect of long-term power frequency electromagnetic field （50 Hz） exposure on the proliferation and apoptosis of human lens epithelial cells （SRAO1/04 cells）. Methods SRA01/04 cells in the exponential growth phase were exposed or sham-exposed to power frequency electromagnetic field （50 Hz, 2.3 naT） for 2 hours per day, 5 days every week. After 11 weeks of exposure, the cells were collected; the cell morphology was observed under a microscope, the cell viability was measured by MTT assay, the cell cycle and apoptosis were examined by flow cytometry, and the protein expression levels of cyelin D and proliferating cell nuclear antigen （PCNA） were determined by western blot. Results Compared with the sham-exposed SRA01/04 cells, most exposed cells became rounded and more stereoscopic, and heterochromatin gathered near the nuclear membrane in some exposed cells. The MTT assay showed that the viability of exposed cells was significantly increased compared with that of the sham-exposed cells （P〈0.05）. Long-term power frequency electromagnetic field exposure led to significantly increased number of ceils in S phase （P〈0.05）, and the proliferation index was significantly higher in the exposed cells than in the sham- exposed cells （P〈0.05）. There was no significant difference in apoptotie rate between the exposed cells and sham-exposed cells （P〉0.05）. The exposed cells had significantly higher protein expression levels of cyclin D and PCNA than the sham-exposed cells （P〈0.05）. Conclusion Long-term power frequency electromagnetic field exposure can promote cellular proliferation and change cell cycle in SRA01/04 cells, but it has no marked effect on the apoptosis of SRA01/04 cells.