Optimization of Low Voltage and High Frequency in vitro and in vivo for clinical application.

Abstract

Recently, electrochemotherapy using low voltage and higher repetition frequency (LVHF ECT) has been shown to be effective in inhibiting tumor growth and cell permeabilization. Low voltage high-frequency electrochemotherapy was developed and optimized in vitro and in vivo which may be used in the clinic.For this purpose, we used bleomycin to evaluate the permeabilization of MCF7 cells caused by low voltage (50 -150 V/cm) and higher repetition frequency (4-6 kHz) electric pulses. In continuation of the procedure, the optimal parameters for electrical pulses were obtained in vitro and then applied to SMMT established in Balb/c  mice. The comparison was made with tumors that received electric pulses alone, electrochemotherapy (with selected protocols of in vitro study), bleomycin alone, and untreated controls.In vitro: we show that cell reversible permeabilization using low electric field strength with higher repetition frequency is achievable.In vivo: our data demonstrate significant differences in tumor volumes and the curability rate between mice treated by LVHF ECT compared to other groups. After LVHF ECT, the number of TUNEL-positive cells in the tumor increased and NHG grade of tumors decreased. LVHF ECT is an effective technique for tumor treatments that reduces muscle contractions and eliminates edema seen in standard ECT. Therefore, it has the potential to be used in clinics.