This was a study aimed to observe the proliferating ability inhibited by energy controllable steep pulse (ECSP) and to detect the expression of gene with relation to the proliferating ability of the tumor in breast cancer cell line; the possible mechanisms were also addressed. Human breast cancer cell line MDA-MB-231 was treated with ECSP; the apoptosis and the expression of tumor suppressor gene--Rb genes and E2F1 genes in ECSP group and control group were detected by TUNEL staining and Reverse Transcripitional PCR respectively. ECSP was found to inhibit the proliferating ability of breast cancer cells markedly, the cell amount in ECSP group decreased and the TUNEL positive cells increased obviously, compared to control; 24 hours after treatment the expression of Rb genes mRNA increased, whereas the expression of E2F1 mRNA decreased. These findings indicate that the proliferating ability of breast cancer cells can be inhibited by ECSP markedly, the apoptosis of breast cancer cell can be induced by ECSP, and the Rb genes and E2F1 genes may be involved in the course.
Apoptosis ; radiation effects ; Breast Neoplasms ; pathology ; Cell Line, Tumor ; Cell Proliferation ; radiation effects ; Electric Stimulation Therapy ; methods ; Electromagnetic Fields ; Electroporation ; methods ; Female ; Humans

In these years, the electrical technology is widely applied in the study of biomedical engineering. Using electroporation therapy (EPT) to treat tumor is associated with biomedical engineering, electrical new technology, computer technology and microelectronic technology, which is a new marginal subject. Many experts have studied the mechanism and clinical treatment of the cell membrane electroporation phenomenon under electrical fields. These researches have shown that the membrane electroporation can stimulate the transport and intake of various drugs, which improves the tumoricidal effect of these drugs. The researchers have also been exploring the phenomenon that irreversible electrical breakdown (IREB) of cell membrane under high electrical fields and steep pulses leads to the death of tumor.
Cell Membrane ; ultrastructure ; Electrochemotherapy ; Humans ; Neoplasms ; drug therapy ; Research ; trends

This study was conducted to observe the lethal effects of steep pulsed electric field(SPEF) on the cancerous squamous cells in BALB/c mice. Female mice were inoculated with the solution of cervical cancer cells line. The tumor-bearing mice of the experiment group were exposed to SPEF. Then, the histomorphological changes were examined and compared between experiment group and control group. The histological and antitumor assay showed that SPEF could selectively injure tumor cells and inhibit cell proliferation. After treatment, pyknosis, karyoclasis and karyolysis of cancer cells were observed under light and electron mircroscope. More serious changes appeared some days later. These results indicate that SPEF have lethal effects on cervical cancer. It may prolong the survival period of tumor-bearing mice.
Animals ; Cell Line, Tumor ; Cell Proliferation ; Electromagnetic Fields ; Electroporation ; methods ; Female ; Mice ; Mice, Inbred BALB C ; Neoplasm Transplantation ; Uterine Cervical Neoplasms ; pathology

To assess study the cytocidal and inhibitory effects of steep pulsed electric fields (SPEFs) on ovarian cancer cell line SKOV3, the cancer cell suspension was treated by SPEFs with different parameters (frequency, pulse duration, peak value of voltage). Viability rate and growth curves of two test groups (high dosage and low dosage of SPEFs) and one control group were also measured. The DNA contents and cell cycle were analyzed by flow cytometry (FCM). Different dosing levels of SPEFs exerted obviously different effects on cancer cell viability. With the enhancement of each pulse parameter, the viability rate was promoted and the inhibitory effect on the proliferation of treated cells was more evident. The cells exposed to SPEFs grew slower than the control. The ratio of S+G2/M phase cells was decreased, which restrained the DNA synthesis and division, but the ratio of G0/G1 phase cells was increased in the treated groups. It was also indicated that the SPEFs blocked the cell transition from G0/G1 phase to S+G2/M phase. There was a significant difference in cell cycle between treated group and control group (P<0.01). Lethal effects of SPEFs were represented by inhibiting the cancer cell proliferation at the cell level and by influencing the cell cycle at the DNA level.
Adenocarcinoma ; pathology ; Cell Cycle ; radiation effects ; Cell Line, Tumor ; Cell Proliferation ; radiation effects ; DNA ; analysis ; Electromagnetic Fields ; Electroporation ; Female ; Flow Cytometry ; Humans ; Ovarian Neoplasms ; pathology ; Pulse

This experiment was designed to study the apoptosis and related mechanism of adherent liver tumor cells (SMMC-7721) and adherent normal liver cells (HL-7702) when they were exposed to the steep pulse generated by the steep pulse apparatus for tumor treatment. The results showed that the steep pulse of 200 V could induce tumor cells apoptosis. The tumor cells presented with their apoptosis when they were exposed to the steep pulse from 200 V to 250 V. Laser scanning confocal microscopy was used to make a real time study of calcium burst when the adherent tumor cells were exposed to the steep pulse. The results showed:On the condition of no extracellular Ca2+, the concentration of Ca2+ in tumor cells exposed to the steep pulse of 150 V did not change; the concentration of Ca2+ in tumor cells exposed to the steep pulse of 200 V decreased; the concentration of Ca2+ in tumor cells exposed to the steep pulse of 250 V decreased more evidently. On the condition of existing extracellular Ca2+, the concentration of Ca2+ in tumor cells exposed to the steep pulse of 150 V did not change; the concentration of Ca2+ in tumor cells exposed to the steep pulse of 200 V decreased little; the concentration of Ca2+ in tumor cells exposed to the steep pulse of 250 V reduced little, too. Maybe the change of calcium burst in the tumor cells is the mechanism of apoptosis when cells are exposed to the steep pulse.
Apoptosis ; radiation effects ; Calcium ; metabolism ; Electricity ; Electromagnetic Fields ; Hepatocytes ; cytology ; pathology ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Microscopy, Confocal ; Tumor Cells, Cultured

Pulsed electric fields (PEFs) with fixed frequency, width and gradually increased peak value of voltage was applied to 30 healthy rabbit liver tissues. The specific aims were to explore the feasibility of establishing a model of in vivo PEFs distribution in healthy rabbit liver tissues and to provide important references for clinical electrochemotherapy and for electrotransfer. Repeated experiment and self-comparison statistics design were implemented. The rabbit underwent the experiment under intravenous anesthesia and their liver tissues, after exposure to PEFs, were sent for HE staining. Necrotic borderline was visible 3 days after PEFs application, the necrotic shape of concentric circle was evident around the electrodes under optical microscope at lower voltage, as voltage increasing, two necroses in the shape of concentric circle gradually enlarged; nuclei with chromatin condensation, fragmentation and lysis alterations were seen in the middle region between the needles; concentric circles changed into ellipse fusiform and finally overlaped each other forming irregular necrosis contours. Cell cavitation and tissues ischemia were also observed within electric field. The shape of tissue necrosis from the experiment was noted to correlate with theoretic simulation of electric field distribution. Therefore, rabbit liver tissues can be a good carrier for in vivo modeling of electric field distribution when the lethal effects of PEFs in tissues are investigated. PEFs also show safety for the surrounding normal tissue while causing damage or injury to the target area therapeutically.
Animals ; Electricity ; adverse effects ; Electrochemotherapy ; Liver ; pathology ; Male ; Models, Theoretical ; Necrosis ; Rabbits

This experimental study was designed to investigate the effects and the expressions of microvessel density (MVD), vascular endothelial growth factor (VEGF) on the transplanted tumor in the rat model with Walker-256 after energy controllable steep pulse(ECSP). The experiment revealed that the steep pulse electrical field has better effect on tumor, compared with the control. The positive cell staining intensity of VEGF in the control group was significantly higher than that in ECSP group (P < 0.05). The number of MVD in the tumor tissues of ECSP group was significantly lower than that of tumor control group (P < 0.05). These results showed that ECSP could inhibit the growth and angiogenesis of tumor and its pathway is to down-regulate the expression of VEGF possibly.
Animals ; Carcinoma 256, Walker ; blood supply ; therapy ; Electric Conductivity ; Electric Stimulation Therapy ; methods ; Electromagnetic Fields ; Electroporation ; methods ; Female ; Male ; Neovascularization, Pathologic ; Rats ; Rats, Wistar ; Vascular Endothelial Growth Factor A ; metabolism

Pulsed electric fields can induce various kinds of biological effects that are essentially different from the normal electric fields, especially the interactions of Nanosecond Pulsed electric field (nsPEF) with cells. The biological effects of different pulsed electric fields on cell membranes, cytoplasmic matrixes, cell growth are introduced in this paper. Based on these effects, some applications of pulsed electric fields in cancer therapy, gene therapy, and delivery of drugs are reviewed in details.
Cell Membrane ; metabolism ; radiation effects ; Cell Physiological Phenomena ; Electromagnetic Fields ; Electrophysiology ; Electroporation ; Genetic Therapy ; methods ; Neoplasms ; therapy

Experimental research of injury on tumor tissue in vitro is conducted with homemade energy-controllable steep pulse device. With the comparison of histological assay results between treatment group and non-treatment group, basic phenomenon of electrochemical reaction and pathology reaction of tumor tissue during the experiment is observed. The results showed the irreversible breakdown penetrating effect of energy-controllable steep pulse on tumor cells and the feasibility of this therapy are also demonstrated. These results provide a consolidate theoretic and applicable basis for further study on mechanism and animal experiment in vivo.
Electric Stimulation Therapy ; instrumentation ; methods ; Electromagnetic Fields ; Female ; Humans ; In Vitro Techniques ; Male ; Middle Aged ; Neoplasms ; pathology ; therapy

In recent years, many experts have done some researches on experiment and mechanism of intracellular electromanipulation (IEM) under nanosecond pulsed electric field (nsPEF). The experiment results have shown that nsPEF could not induce electroporation of cell membrane, but could induce intracellular effects such as apoptosis, calcium release, enhancement of gene expression, and fragmentation of DNA and chromosome. In order to account for the phenomenon, researchers believe that when the pulse width of the pulsed electric field is larger than the charging time of plasma membrane, the pulsed electric field mainly targets on the outer membrane of cell; and that the effect of the pulsed electric field on nucleus and nuclear membrane increases with the decrease of the pulse width. It is also believed that the effect of electroporation changes from the outer membrane to intracellular electromanipulation when the pulse width decreases to a value being smaller than the charging time of plasma membrane.
Apoptosis ; Calcium ; metabolism ; Cell Membrane ; metabolism ; Cell Nucleus ; metabolism ; Cell Physiological Phenomena ; Electromagnetic Fields ; Electroporation ; Gene Expression