The effect of temperature-control microwave on HELA and MG-63 cells

Context: Hyperthermia has now been used to treat many kinds of solid malignancies. However, the applied thermal parameters about heat temperature and time varied all over the world, and no consensus about the optimal formula had been reached. Microwave ablation, as one of thermal ablation methods, is usually applied based on the fixed parameters of power and duration. As a result, too high temperature or overheating might not be avoided and excessive heating might cause some additional side effects to normal tissues. Aims: To explore the optimal parameters of power and duration for the HELA and MG-63 cells in vitro. Settings and Design: With a temperature-controlled microwave workstation, a microwave thermal ablation experiment was performed in vitro. Subjects and Methods: The HELA and MG-63 cells were heated with 40 degrees C, 45 degrees C, 50 degrees C, 55 degrees C, and 60 degrees C lasting for 5-30 min, respectively. Then, the cell viability was detected using four methods: Flow cytometer assay, nicotinamide adenine dinucleotide-diaphorase staining, Calcein-acetoxymethyl ester staining immediately after treatment, and CCK-8 assay 24 h later. Results: The temperature-controlled microwave has an excellent ablation effect on both cell lines. Furthermore, when the thermal stimulation reached 55 degrees C 25 min and 55 degrees C 20 min for the HELA and MG-63 cells, respectively, or 60 degrees C 5 min for both, all the viability indexes indicated immediately devitalization. Conclusion: It presented a preliminary minimum lethal dose of heat was validated on the cellular level in vitro, which should be verified and corrected further in vivo.