微波辐射对兔晶状体水化程度及上皮细胞蛋白激酶C-α和转录因子表达的影响

Effects of microwave radiation on lens hydration and expression of PKC-α and transcription factors in lens epithelial cells

目的观察低强度微波对体外培养兔晶状体水化程度及晶状体上皮细胞的影响,检测微波辐射后上皮细胞内蛋白激酶C-α(PKC-α)和转录因子c-fos、c-jun表达的改变。方法体外培养的兔晶状体暴露在频率为2450MHz、功率密度分别为0.5、2.0和5.0mW/cm^2的电磁场环境下,8h后测定晶状体的水化程度,相差显微镜和Hoechst33258染色观察晶状体上皮细胞形态学的改变,2.0mW/cm^2微波分别辐射2、4、6和8h后Western印迹法分析上皮细胞PKC-α和转录因子c-fos、c-jun的表达。结果2.0和5.0mW/cm^2微波连续辐射8h后,晶状体的水化程度增加,分别为85.74%±2.37%、87.14%±3.64%,与对照组(79.07%±2.11%)比较,差异有统计学意义(P<0.05),同时可见晶状体前囊膜的上皮细胞排列紊乱,染色质凝聚,0.5mW/cm^2组未见明显改变。2.0mW/cm^2微波分别辐射4、6和8h后,胞浆内PKC-α的表达降低,而胞膜PKC-α的表达量在辐射后升高,c-fos和c-jun的表达均较辐射前升高,差异有统计学意义(P<0.05,P<0.01)。结论高于2.0mW/cm^2的微波辐射可通过诱导PKC-α跨膜转位而激活PKC-α,将刺激信号传入细胞内,进一步引起转录因子c-fos和c-jun的高表达,最终产生相应的生物学效应,使体外培养的兔晶状体及上皮细胞产生损伤。

Objective To observe the effects of low power microwave radiation on lens hydration and lens epithelial cells in vitro, and detect the expression of PKC-α, c-fos and c-jun in lens epithelial cells. Methods Rabbit lens were exposed to microwave radiation with frequency of 2450 MHz and power density of 0.5, 2.0 and 5.0 mW/cm^2 in vitro. The hydration of lens was measured after 8 hours. Morphological changes of lens epithelial cells were observed using a phase-contrast microscope and Hoechst 33258 staining. Expression of PKC-α, c-fos and c-jun were analyzed using gel electrophoresis and western blot analysis. Results After 2.0 and 5.0 mW/cm^2 microwave radiation, the hydration of lens was increased compared to control groups （P〈0.05）, the shape of lens epithelial cells showed shrinking and disorder and cells nuclei appeared chromatin condensation. There was no change of lens and lens epithelial cells after 0.5 mW/cm^2 microwave radiation. The expression of PKC-α was significantly increased in cell membrane, however, decreased in cell cytoplasm after 2.0 mW/cm^2 microwave radiation for 2, 4, 6 and 8 hours. There was significantly increased expression of c-fos and c-jun protein compared with control groups （P〈0.05, P〈0.01 ）. Conclusion Low power microwave radiation higher than 2.0 mW/cm^2 can activate PKC-α by increasing its expression in cell membrane, then induce high expression of c-fos and c-jun, which may relate to cellular signaling pathway of microwave radiation injury to lens and lens epithelial cells.