50 Hz magnetic field influences caspase-3 activity and cell cycle distribution in ionizing radiation exposed SH-SY5Y neuroblastoma cells

Abstract

Overview

Earlier evidence suggests extremely low frequency magnetic fields (ELF MFs) can modify the effects of carcinogenic agents. However, studies with ionizing radiation as the co-exposure agent are limited and results have been inconclusive. This research investigated whether exposure to 50 Hz magnetic fields (MFs), alone or combined with ionizing radiation, alters cellular processes relevant to cancer in human SH-SY5Y neuroblastoma cells.

Materials and Methods

• Cells were sham exposed or exposed to 100 or 500 μT MF for 24 hours, either prior to or following ionizing radiation (0, 0.4, or 2 Gy).
• Assays performed: viability, clonogenicity, reactive oxygen species (ROS) levels, caspase-3 activity, and cell cycle distribution.
• Cell cycle distribution and ROS measured via flow cytometry, using various staining methods.

Findings

• Increased caspase-3 activity was observed in cells exposed to 500 μT MF before or after ionizing radiation.
• Exposure to 500 μT MF after ionizing radiation reduced S-phase cell population.
• No significant changes were found in ROS levels, clonogenicity, or viability in the MF-exposed groups compared to shams.
• No effects observed in cells exposed to 100 μT MF.

Conclusion

Only exposure to 500 μT magnetic flux density had significant effects on SH-SY5Y cells. While the changes were relatively small, they provide insight into how magnetic fields may modify the impact of ionizing radiation—a known cancer risk. Notably, the increase in caspase-3 activity did not translate into changes in apoptosis markers in the cell cycle, and MF exposure timing relative to ionizing radiation did not alter the magnitude of effects, counter to some prior studies.

⚠️ Important Note: This study demonstrates that high-intensity, extremely low-frequency magnetic fields in combination with ionizing radiation can influence cellular activity related to cancer, supporting evidence of a potential health risk from electromagnetic field exposure.