influence of picosecond pulse electric field to invasive ability of cervical cancer

Objective　To investigate the influence of picosecond pulse electric field (psPEF) to the invasive ability of cervical cancer. Methods　The model of cervical cancer was reproduced in BALB/c nude mice (n=24), and they were randomly divided into four groups (n=6) when the xenografts had grown reaching a diameter of 0.8-1.0cm: control group (psPEF was not given), low field intensity group (50kV/cm), moderate field intensity group (60kV/cm) and high field intensity group (70kV/cm). Seven days after the psPEF treatment, the histomorphological changes were observed with HE staining and transmission electron microscopy (TEM), the expressions of vascular endothelial growth factor (VEGF) and matrix metalloproteinases-9 (MMP-9) were determined with immunohistochemical (IHC) staining, and the changes in protein level of VEGF and MMP-9 were assessed with Western blotting. Results　After psPEF treatment, the area of necrosis was found to be increased with an increase in psPEF intensity. With TEM different degrees of apoptosis and necrosis in tumor cells with an increase of psPEF intensity were found. IHC showed that the number of VEGF and MMP-9 positive cells in cancer tissue was decreased with an increase in psPEF intensity. The average optical density (AOD) of VEGF and MMP-9 proteins decreased significantly in psPEF treatment groups compared with that in control group, and the AOD values in psPEF treatment groups decreased with an increase in psPEF intensity, and the decrease was statistically significant (P<0.05). Western blotting showed the expressive levels of VEGF and MMP-9 proteins declined gradually with an increase in psPEF intensity, and the difference between groups was statistically significant (P<0.05). Conclusion　psPEF may have anti-cervical cancer effects by inhibiting the secretion of VEGF and MMP-9 and reducing the invasive ability of cervical cancer cells. DOI: 10.11855/j.issn.0577-7402.2015.09.03