50Hz极低频电磁场对酵母细胞生长和氧化应激的影响初探

探讨50 Hz极低频电磁场(extremely low frequency electromagnetic fields,ELF-EMF)暴露对酵母细胞的生长、细胞内活性氧(ROS)水平,以及超氧化物歧化酶(SOD)和过氧化氢酶(CAT)两种抗氧化酶活性的影响。测定酵母细胞在50 Hz 6 m T ELF-EMF暴露下的菌落形成数目和生长曲线,及ELF-EMF短期暴露(0.5、1、2 h)和长期暴露(6、12、24、96 h)对细胞内ROS水平,以及SOD和CAT活性的影响。实验结果表明,磁感应强度高达6 m T的ELF-EMF暴露下,酵母细胞的菌落形成数目和生长曲线没有发生显著变化(p0.05)。在暴露2 h内,ELF-EMF可显著提高细胞内ROS水平(p0.01);并显著影响酵母细胞内SOD或CAT活性(p0.05)。但暴露时间超过6 h后,酵母细胞内ROS水平、及SOD和CAT活性与对照组大致相同,没有发生显著变化。实验条件下ELF-EMF暴露对酵母的生长没有显著影响,在短期暴露(2 h内)中,可引起酵母细胞内氧化应激反应;但在长期暴露(6 h后)后,对氧化应激反应没有显著影响。

Extremely low frequency electromagnetic fields do not affect growth and oxidative stress in Saccharomyces cerevisiae

Objective To study whether extremely low frequency electromagnetic fields (ELF-EMF) could affect yeast colonies number, growth, intracellular reactive oxygen species (ROS) levels and activities of antioxidant enzyme superoxide dismutase (SOD) and catalase (CAT). Methods Yeast colonies number and cell growth curve under 50 Hz 6mT ELF-EMF exposures were measured. Intracellular ROS level, SOD activity and CAT activity were measured after short term exposure (0.5, 1 and 2 hour) and long term (6, 12, 24 and 96 hour) exposure. Results The yeast cells exposed to ELF-EMF did not show statistically significant changes colonies number and growth curve compared with the control cells (p>0.05). In short-term (no more than 2 hours) exposure, ELF-EMF could significantly improve intracellular ROS level and activities of SOD and CAT, however, these effects disappeared after long-term (after 6 hours) exposure. Conclusion It could be concluded that ELF-EMF exposure has no effect on cell growth, but can elicit oxidative stress in yeast cells in short-term, but not long-term, ELF-EMF exposure.