Exploration Of High Frequency Electric Pulse On Tumor Ablating

Cancer means malignant tumor originated from epithelial cells,which is one of the three major killers of human health.At present,the clinical treatment of cancer mainly has traditional surgical excision,radiotherapy and chemotherapy,but these methods bring pains to patients both on physical and mental.New minimally invasive technique such as radiofrequency ablation,microwave ablation,ablation and focused ultrasound ablation have limitation that may cause damage to surrounding tissue or organs because of the heat sink effect.Irreversible electroporation(IRE),as a non-thermal ablation method of tumor that can ablate tumor near blood vessel and bile duct,has attracted more and more attention in clinic.With more and more widespread of application,problems are beginning to crop up.One is that the existence of ablation dead zone due to the inhomogeneous distribution of electric field,another is patients feel pains of contracting muscle involuntary under stimulated by electric pulse.This subject improve the electric pulse based on traditional IRE,using electric pulse with higher frequency,and bipolar pulse that have alternative positive and negative electrode,which can solve the problem in theory.From the biological point of view,we did experiment in the level of cells,tissues and solid tumors in animals to explore the killing effect of high frequency pulse on tumor ablating.The results could promote the clinical application of two new types of pulses.For monopolar high frequency pulse,we detected the stimulated normal epidermal cells and melanoma cells with MTT,to determine the killing effect of different frequency pulses via relative living cells.Stained cells with Annexin V-FITC/PI and detected with flow cytometer to explore the cell death pathway under electric pulse with different frequency or electric field intensity.Stained cell membrane with DiI and observed cell membrane perforation under electrical pulses.For bipolar high frequency pulse,detected the stimulated cells with CCK-8,determine the killing effect of different frequency or duty ratio pulses via relative living cells.Stained cells with Annexin V-FITC/PI and detected with flow cytometer to explore the cell death mode under electrical pulse with different frequency.Stimulated rabbit liver and stained paraffin section with hematoxylin and eosin to observe the electric-field distribution on tissue.Established animal model,stimulated with IRE and two new types of pulse,measured and stained with hematoxylin and eosin to determine tumor ablation.Conclusions are as follows:(1)On the premise that total energy is consistent,the killing effect of high frequency pulse increase with the rise of pulse width or electric field intensity,but unrelated to duty ratio.(2)Monopolar and bipolar high frequency pulse can reach the same killing effect as traditional pulse,IRE and monopolar pulse mainly cause cell death with irreversible perforation on cell membrane,while bipolar pulse makes cells apoptosis.(3)High frequency pulse,especially bipolar high frequency pulse,have more uniform electric field distribution on animal tissue and solid tumor than traditional IRE pulse.