Abstract: Objective To explore the feasibility and safety of high-frequency pulse electric field ablation in renal artery denervation. Methods Human neuroblastoma cell SH-SY5Y and rat thoracic artery smooth muscle cell A7r5 cells were ablated under the voltage of 500 V and 700 V, the number of pulses 500 and pulse mode: single pulse, long pulse, bidirectional pulse 5-5-5-5, bidirectional pulse 5-3-3-5 and bidirectional pulse 7-3-3-7. The cell survival rate was detected by MTT method. Electrodes were implanted by percutaneous femoral artery puncture, and renal artery sympathetic nervous system was ablated in four Bama miniature pigs. Surgical tissue melting sections were removed and observed under the microscope to verify the ablation effect. Results Under the microscope, A7r5 cells and SH-SY5Y cells were nearly completely apoptotic at 500 V and 700 V, respectively. When the voltage was 500 V, the survival rate was higher in SH SY5Y cells than that of A7r5 cells under the same pulse (P＜0.01). There was no significant difference in the survival rate of A7r5 cells between single pulse and long pulse, but it was lower than that of bidirectional pulse 5-5-5-5 (P＜0.05). The survival rate increased gradually in bidirectional pulse 5-5-5, 5-3-3-5 and 7-3-3-7 (P＜0.05). When the voltage was 700 V, the cell survival rate was higher in A7r5 cells after two-way pulse 5-3-3-5 ablation than that of two-way pulse 5-5-5-5 (P＜0.05). There was no significant difference in cell survival rate between other pulse modes. During the ablation of porcine renal artery, slight convulsions occurred under the bidirectional pulse 5-5-5-5 mode. The ablation process of bidirectional pulse 5-3-3-5 and 7-3-3-7 was stable. After ablation, the staining of renal artery showed focal rupture of adventitia and media, wall fibrosis, local endothelial damage and thrombosis. Masson staining showed arterial wall fibrosis, and silver nitrate staining showed light brown nerve tissue and nerve cell death. Conclusion High frequency pulsed electric field has good ablation effect on smooth muscle cells A7r5 and nerve cells SH-SY5Y. High frequency pulsed electric field can ablate porcine renal artery sympathetic nerve. Bidirectional asymmetric pulse 5-3-3-5 can effectively avoid muscle contraction, which is the optimal parameter array.

Key words: ablation techniques, renal artery, electroporation, sympathetic nervous system, renal artery denervation, irreversible electroporation