The Antitumor Effect Of Low Voltage Electric Pulses On Melanoma Bearing Mouse

Objective:To investigate antitumor effects of the low voltage electric pulses (LVEPs) on melanoma bearing mice.Methods:Tumor models in BALB/c mice were established by subcutaneously inoculating them with B16F10 melanoma cells, these mice were randomly divided into control group and treat groups which were exposed to electric pulses with different frequency (10,20,30)hz for 30 minutes per day and time span is 20 days. Every day tumor size was measured, Morphological changes of tumors were observed with HE staining. The expression of caspase-3 and matrix metalloproteinase-9 (MMP-9) mRNA were tested by real-time quantitative polymerase chain reaction (qRT-PCR),the expression of caspase-3 and MMP-9 protein were detected by immunochemistry.Results:Compared with control group,7 days post-LVEPs treatment the tumor size in 30hz electrical treated group was reduced significantly (P<0.05),14 days post-LVEPs tumor size in 20hz and 30hz treated group were reduced significantly (P<0.05),20 days post-LVEPs tumor size of all treated groups was reduced significantly (P<0.05), and the tumor growth inhibit ratio was increased as time prolonged. More nuclear shrinkage and necrosis of tumor cells were found by light microscope in treated groups when compared with control group. The expression of caspase-3 mRNA and protein significantly increased in the treated groups, the expression of MMP-9 mRNA and protein significantly decreased in the treated groups when compared with control group, and the greater increase in caspase-3 and decrease in MMP-9 were found with frequency increasing.Conclusion:low voltage electric pulses can induce the activation of caspase-3, suppress the expression of MMP-9, and inhibit growth of tumor.