Pilot in vitro and in vivo study on a mouse model to evaluate the safety of transcutaneous low-frequency electrical nerve stimulation on cervical cancer patients

Introduction and hypothesis To clarify whether the pulse electrical field (PEF) caused by transcutaneous low-frequency nerve electrical stimulation (TENS) enhances the proliferation of cervical cancer cells, leading to recurrence and metastasis, and the effect of such a PEF on a cervical cancer mouse model. Methods 1. In vitro experiment: SiHa cervical cancer cells treated with one session of microsecond PEFs for 30 min were divided into four groups: three experimental groups and the control group. Cell proliferation and migration were determined by CCK-8 proliferation and Transwell chamber Matrigel migration assay. 2. In vivo experiment: A mouse cancer model was established by subcutaneous implantation of SiHa cells that were then were randomly divided into the TENS group and control group. The former group received one session of TENS treatment and the control group received a sham pulse. The growth trend and tumor volume of each group were compared 28 days after PEF treatment. The proliferation and apoptosis of the tumor were determined by an immunohistochemical method. Results (1) The CCK-8 proliferation assay and cell migration ability showed no difference after PEF stimulation treatment (F = 2.478, P = 0.136 > 0.05 and F = 0.364, P = 0.779). (2) Tumor growth, size and weight showed no significant difference between the two groups. (3) Expression of VEGF, CD34, caspase-3 and Ki-67 in the tumor tissue showed no significant difference between the two groups. Conclusions In vitro and in vivo experiments (mice) showed that the PEF created by TENS had no effect on the proliferation and migration of SiHa cervical cancer cells and also had no effect on the tumor growth, tumor cell apoptosis and proliferation.