Effect of isothermal microwave exposure on the cell cycle

Abstract

In cell biology, it has been known that microwave (MW) has non-thermal effect on cell cycle or cell proliferation. Recently, the next generation microwave heating apparatus (NGMW), which uses semiconductor with digital technology, has been developed. It is much easier to control power of MW, compared to conventional MW. We used this machine to examine the non-thermal effect on cell cycle. When HL-60 human leukemic cells were exposed to 20 or 40 Watts of MW at 37 or 42oC for 30 minutes, percentage of S-phase fraction in DNA histogram, analyzed by flow cytometry, increased dramatically (p = 0.026). When the same experiments were done using Propidium iodide (PI) and MIB-1 double staining, cycling cells increased significantly (p = 0.005). It is suggested that MW has non-thermal effect on cell cycle.