Experimental Research Of Ablation Therapy Using Injectable NaK Alloy Anti-Mice Transplanted Tumor Of EMT6 Breast Cancer Cells

Objective: Liquid alkali metal is newly emerging means of thermo-chemical minimally invasive therapy of malignant tumor.This study is aiming to explore the feasibility by attempting to inject liquid Na K alloy to EMT6 breast tumor on living mice,and dynamic observation is followed to evaluate the efficacy of this approach.Methods: 1 Animals were 15 BALB/c female mice at the age of 6 weeks and weighed about 20 g.2 Liquid Na K alloy was made of solid sodium and kalium in standard condition and reserved in silicone oil.3 Mice EMT6 breast cancer cells were subcultured and made to cells suspension(2×107/ml),then injected 0.2ml of cells suspension to each mice on the right inguinal fold area.4 After inoculation of tumor cells for 10 days,mice were divided into group A and B as the treatment group(the complete ablation group and the partial ablation group),each group had 5 mice and the remaining 5 mice were the control group C.5 The operations were performed in a glass tank with walls to protect operators.Temperatures in tumor center in ablation process were measured and recorded by thermocouple.Thermal effects of mice surface in ablation process were shoot and by thermal infrared imager.6 Injected liquid Na K alloy into EMT6 breast tumor on mice of group A and B by disposable insulin syringe.Mice of group C were not treated.One mouse of each group was chosen to execute and to made residual tissue or tumor tissue into pathological section.Other mice were raised and their tumor volumes were continuously measured for 20 days.Then compared group A and B with group C respectively to find out any difference and significance by Two Way ANOVA statistical analysis.Results: 1 A significant temperature increase as high as 104℃ could be measured in the tumor center during ablation,and the temperature higher than tumor lethal temperature 43℃ lasted about 30 s,which demonstrated the reliability and positivity of killing malignant tumors by means of Na K alloy.Thermal effects of tumor surface were monitored by infrared thermal imager during ablation process.It showed that the temperature outside of tumor was far lower than inside,which provided the basis for realization of minimally invasive ablation in clinical.2 Tumor structure disappeared after ablation of mice in group A,leaving cavity structure and eschar in ablation areas.Pathological section showed that EMT6 breast cancer cells were led to coagulative necrosis after ablation by Na K alloy.Gradually eschar fell off and there was no tumor recurrence.The large proportion of tumor was killed while the residual tumor continued to grow in group B and there were clear boundaries between ablation area and residual tumor tissue according to pathological section.Mice tumor in group C reflected rapid growth trend and tend to invade surrounding structures with a lot of pathological nuclear fissions in cancer cell nuclear.3 Mice tumor volumes of the 3 groups were continuously measured for 20 days.Data was analyzed by Two Way ANOVA statistical analysis.It concluded that there were differences on tumor volume over time compared the experimental groups with the control group(P = 0.0005 < 0.05).There were differences on tumor volumes between group A and C from the 10 th day to the 20 th day(P < 0.05)and there were differences on tumor volumes between group B and C from the 11 th day to the 20 th day(P < 0.05).It means that mice EMT6 tumors at early and middle stage are smaller than tumors on the control group mice after treatment.Conclusions: Injecting liquid Na K alloy to EMT6 mice tumor tissue as an invasive minimally therapy is feasible and effective.Temperature in tumor center rises rapidly and keeps some time during ablation,which reflects the reliability and exact thermal ablation effect by this approach.Surface temperature is far lower than tumor center,which provides the basis for realization of minimally invasive treatment.EMT6 cancer cells turn into thoroughly degeneration necrosis and clear boundaries develop after ablation.Using injectable Na K alloy can thoroughly kill mice transplanted tumor by complete ablation and can restrain the growth of transplanted tumor by partial ablation.