Electrotaxis of alveolar epithelial cells in direct-current electric fields / 中华创伤杂志(英文版)

PURPOSE@#This study aims to elucidate the electrotaxis response of alveolar epithelial cells (AECs) in direct-current electric fields (EFs), explore the impact of EFs on the cell fate of AECs, and lay the foundation for future exploitation of EFs for the treatment of acute lung injury.@*METHODS@#AECs were extracted from rat lung tissues using magnetic-activated cell sorting. To elucidate the electrotaxis responses of AECs, different voltages of EFs (0, 50, 100, and 200 mV/mm) were applied to two types of AECs, respectively. Cell migrations were recorded and trajectories were pooled to better demonstrate cellular activities through graphs. Cell directionality was calculated as the cosine value of the angle formed by the EF vector and cell migration. To further demonstrate the impact of EFs on the pulmonary tissue, the human bronchial epithelial cells transformed with Ad12-SV40 2B (BEAS-2B cells) were obtained and experimented under the same conditions as AECs. To determine the influence on cell fate, cells underwent electric stimulation were collected to perform Western blot analysis.@*RESULTS@#The successful separation and culturing of AECs were confirmed through immunofluorescence staining. Compared with the control, AECs in EFs demonstrated a significant directionality in a voltage-dependent way. In general, type Ⅰ alveolar epithelial cells migrated faster than type Ⅱ alveolar epithelial cells, and under EFs, these two types of cells exhibited different response threshold. For type Ⅱ alveolar epithelial cells, only EFs at 200 mV/mm resulted a significant difference to the velocity, whereas for, EFs at both 100 mV/mm and 200 mV/mm gave rise to a significant difference. Western blotting suggested that EFs led to an increased expression of a AKT and myeloid leukemia 1 and a decreased expression of Bcl-2-associated X protein and Bcl-2-like protein 11.@*CONCLUSION@#EFs could guide and accelerate the directional migration of AECs and exert antiapoptotic effects, which indicated that EFs are important biophysical signals in the re-epithelialization of alveolar epithelium in lung injury.

Tecnología emergente: Campo de pulsos eléctricos (PEF) para el tratamiento de alimentos y su efecto en el contenido de antioxidantes

RESUMEN Los métodos de conservación de alimentos no-térmicos han generado un considerable interés en la industria alimentaria como potencial alternativo a los métodos tradicionales de procesamiento. Uno de los métodos no-térmicos más estudiados es el de campos eléctricos pulsados o PEF (Pulsed Electric Fields). La aplicación de PEF en el procesamiento de alimentos permite limitar la exposición a altas temperaturas y reducir la necesidad de aditivos alimentarios. En PEF, se expone al alimento a pulsos eléctricos generando poros en la membrana celular, este fenómeno se le conoce como electroporación. La electroporación promueve la inactivación de organismos patógenos, reduce la actividad enzimática, favorece la transferencia de masa, mantención de color, sabor y contenido de compuestos antioxidantes, mejora la eficiencia en el procesamiento de alimentos y mantiene de cualidades organolépticas que son atractivas tanto para el consumidor como también para la industria. Los antioxidantes son sustancias capaces de proteger a las células de los radicales libres. La acción de los antioxidantes es de interés tanto del punto de vista sanitario, como industrial. Existe abundante evidencia que asocia el consumo de antioxidantes como factor protector ante enfermedades. Por otro lado, los antioxidantes cumplen un rol importante en la duración de los alimentos ya que actúan como conservantes, prolongando su vida útil. La utilización de PEF, respecto a otras tecnologías para el procesamiento de alimentos, ha demostrado un aumento en la extracción, menor pérdida por temperatura y una mayor disponibilidad de compuestos de interés, incluidos antioxidantes.

ABSTRACT Non-thermal food preservation methods have gained considerable interest in the food industry as a potential alternative to traditional processing methods. One of the most studied non-thermal methods is Pulsed Electric Fields (PEF). The application of PEF in food processing allows limiting exposure to high temperatures and reducing the need for food additives. In PEF, food is exposed to electrical pulses generating pores in the cell membrane, this phenomenon is known as electroporation. Electroporation promotes the inactivation of pathogenic organisms, reduces enzyme activity, favors mass transfer, maintains color, flavor and antioxidant compound content, improves food processing efficiency and maintains organoleptic qualities that are attractive to both the consumer and the industry. Antioxidants are substances capable of protecting cells from free radicals. The action of antioxidants is of interest both from a health and industrial point of view. There is abundant evidence that associates the consumption of antioxidants as a protective factor against diseases. On the other hand, antioxidants play an important role in the shelf life of foods as they act as preservatives, prolonging their shelf life. The use of PEF, compared to other food processing technologies, has shown an increase in extraction, lower temperature loss and greater availability of compounds of interest, including antioxidants.

Immune response triggered by the ablation of hepatocellular carcinoma with nanosecond pulsed electric field / 医学前沿

Nanosecond pulsed electric field (nsPEF) is a novel, nonthermal, and minimally invasive modality that can ablate solid tumors by inducing apoptosis. Recent animal experiments show that nsPEF can induce the immunogenic cell death of hepatocellular carcinoma (HCC) and stimulate the host's immune response to kill residual tumor cells and decrease distant metastatic tumors. nsPEF-induced immunity is of great clinical importance because the nonthermal ablation may enhance the immune memory, which can prevent HCC recurrence and metastasis. This review summarized the most advanced research on the effect of nsPEF. The possible mechanisms of how locoregional nsPEF ablation enhances the systemic anticancer immune responses were illustrated. nsPEF stimulates the host immune system to boost stimulation and prevail suppression. Also, nsPEF increases the dendritic cell loading and inhibits the regulatory responses, thereby improving immune stimulation and limiting immunosuppression in HCC-bearing hosts. Therefore, nsPEF has excellent potential for HCC treatment.

Effect of negative polarity electret on dielectric properties and hypoglycemic effects of insulin / 第二军医大学学报

Objective To study the effect of negative polarity electret on the dielectric properties and structure of insulin, and to observe the influence of electrostatic field on the hypoglycemic effect of insulin. Methods Negative polarity electrets of –500, –1 000 and –1 500 V were prepared using polypropylene film by a gate voltage corona charging system, and were used to treat insulin, respectively. The equivalent surface potential of each electret within 48 h was measured by compensation method. The relationship between the polarization of insulin and the electrostatic field was measured by the dielectric constant d33. The influence of the electrostatic field on the molecular structure of insulin was examined by nuclear magnetic resonance and gel electrophoresis. Insulin exposed to –500, –1 000 and –1 500 V negative polarity electret for 12 h was injected into the diabetic rats, and then the hypoglycemic effect of insulin were observed. Results The potential differences between the two sides of insulin solution effected by negative polarity electrets with different surface potentials were exponentially increased within 0-4 h and gradually became constant at 4-48 h. Compared with the insulin patch treated by non-electret electrostatic field, the d33 values of insulin patch effected by –500, –1 000 and –1 500 V electret for 12 h were increased by 14.7 times, 26.7 times and 45.0 times, respectively, and all tended to be stable after 12 h. The spatial structure of insulin exposed to electrostatic field did not change, but the hydrogen bond content of most perssad was decreased; the proportion of monomers of the insulin was increased, and the main structures of the insulin were monomers and dimers. Compared with the electret-free insulin treatment group, the blood glucose content of diabetic rats treated with the –500 V and –1 000 V negative polarity electrets insulin for 8 h were decreased by 50.9% and 22.1%, respectively (P<0.05). Conclusion Negative polarity electret can further improve the hypoglycemic effect of insulin.

Influence of electric fields on migration behavior and morphology of endothelial progenitor cells / 重庆医学

Objective To investigate the influence of external electric fields on migration behavior and morphology of endo‐thelial progenitor cells (EPCs) cultured in vitro .Methods The in vitro cultured 3-4 generation EPCs were continuously stimula‐ted by direct‐current electric field with the field intensity of 0 mV/mm(group Ⅰ ) ,100 mV/mm(group Ⅱ) ,200 mV/mm(group Ⅲ) and 300 mV/mm (group Ⅳ )for 3 h .The live cell station was used to real time record the cell migration track and morphology change of EPCs .The influence of external electric field on the EPCs migration behavior and morphology was analyzed .Results Un‐der the stimulation of the direct‐current electric field with the intensity of group Ⅳ ,group Ⅲ and group Ⅱ ,the cells were directly migrated to anode ,while the cells under group Ⅰ displayed the random motion .The track migration velocity(Vt)、displacemnt ve‐locity(Vd) and electric field direction migration rate(Vx) were(98 .86 ± 6 .00) ,(63 .78 ± 2 .81) ,(63 .15 ± 2 .88)μm/h for the groupⅣ ,(88 .06 ± 8 .83) ,(35 .90 ± 1 .22) ,(34 .20 ± 1 .57)μm/h for the groupⅢ ,(42 .28 ± 2 .25) ,(13 .29 ± 0 .37) ,(12 .39 ± 0 .51)μm/h for the groupⅡ ,which were significantly higher than(37 .39 ± 2 .42) ,(6 .99 ± 0 .31) ,(4 .62 ± 0 .40)μm/h for the groupⅠ (P<0 .01) ,moreover Vt ,Vd and Vx in the group Ⅲ were significantly higher than those in the group Ⅱ andⅠ (P<0 .01) .EPCs had obvious morphological changes under the electric field action ,such as elongation and the cellular long axis parallel to the electric field direction .Conclusion External direct current electric fields may induce the directed migration of EPCs towards the anode ,ac‐celerates the migration rate ,moreover has obvious influence on EPCs morphology .

LOS CAMPOS BIOELÉCTRICOS Y ALGUNAS APLICACIONES MÉDICAS - REVISIÓN / BIOELECTRIC FIELDS AND SOME MEDICAL APPLICATIONS - REVIEW

Con las investigaciones de Emil Du Bois-Reymond, uno de los fundadores de la electrofisiología, se dio inicio a la era de la bioelectricidad. DuBois documentó en detalle actividades eléctricas asociadas con excitación nerviosa, contracción muscular y procesos de cicatrización. En la actualidad es reconocido que los campos eléctricos (CE) están presentes en los organismos vivos y que direccionan e influyen procesos biológicos como la embriogénesis, regeneración y cicatrización de heridas. Diversos estudios han demostrado como los CE interfieren en la biosíntesis y la migración celular, dando lugar a nuevas estrategias para la reparación de ligamentos y regeneración de tejidos. En la actualidad las corrientes y CE biológicos suministran información necesaria para diversos tipos de diagnósticos y tratamientos. En este trabajo se hace una revisión de algunos estudios realizados alrededor de la generación de campos bioeléctricos endógenos, sus sustratos biológicos y aplicaciones médicas.

The era of bioelectricity began with the investigations of Emil Du Bois-Reymond, one of the founders of electrophysiology. DuBois documented in detail electrical activities associated with nerve excitation, muscle contraction and healing processes. It is currently recognized that electric fields (EFs) are present in living organisms and that they direct and influence biological processes such as embryogenesis, regeneration and wound healing. Several studies have shown how EFs interfere with biosynthesis and cell migration, leading to new strategies for repairing ligaments and for tissue regeneration. At present, biological EFs and currents provide information needed for different types of diagnoses and treatments. This paper reviews some studies focused on the generation of endogenous bioelectric fields, their biological substrates and medical applications.

The killing effect of pulsed electric fields(PEFs)with different frequencies on human ovarian carcinoma cell line SKOV3 in vitro and subcutaneously transplanted tumor in vivo / 中华物理医学与康复杂志

Objective To investigate acute cell damage and delayed inhibition effects by pulsed electric fields(PEFs)with different frequencies on human ovarian carcinoma cell line SKOV3 in vitro and in subcutaneous transplanted tumor of human SKOV3 in BALB/c nude mice,and evaluate the potential use of relatively higher frequency PEFs to reduce unpleasant sensations without decreasing therapeutic effects in clinical electrochemotherapy.Methods Firstly,SKOV3 cell suspension were exposed to PEFs with gradient increasing frequencies(1,60,1 000,5 000 Hz)and voltages(50,100,150,200,250,300,350,400 V),respectively.MTT assay was used to determine the acute cell damage.Then PEFs with gradient increasing frequencies(1,60,1 000,5 000 Hz)and fixed voltage (250 V)were applied to the subcutaneously transplanted tumor,in vivo antitumor assay was used to observe the delayed inhibition effect;histological changes were observed by light and electron microscope. Results The 1 Hz PEFs has similar cytotoxic effects with 5 kHz,and no significant difference of delayed tumor inhibition effect on subcutaneous transplanted tumor among all groups exposed to different frequencies of PEFs(P＞0.05).Histological observation showed acute damage in all exposed groups.and only in 5 kHz group was induced apoptotic effect observed.Conclusions PEFs with relatively higher frequency can achieve similar tumor killing effect with the low frequency PEFs,and it can also induce apoptosis.Relatively higher frequency PEFs show therapeutic potentials for reducing unpleasant sensations in clinical electrical treatment of tumor.

Exploring the use of natural antimicrobial agents and pulsed electric fields to control spoilage bacteria during a beer production process / Exploración del uso de agentes antimicrobianos naturales y de campos eléctricos pulsantes para el control de bacterias contaminantes durante el proceso de elaboración de cerveza

Different natural antimicrobials affected viability of bacterial contaminants isolated at critical steps during a beer production process. In the presence of 1 mg/ml chitosan and 0.3 mg/ml hops, the viability of Escherichia coli in an all malt barley extract wort could be reduced to 0.7 and 0.1% respectively after 2 hour- incubation at 4 °C. The addition of 0.0002 mg/ml nisin, 0.1 mg/ml chitosan or 0.3 mg/ml hops, selectively inhibited growth of Pediococcus sp. in more than 10,000 times with respect to brewing yeast in a mixed culture. In the presence of 0.1mg ml chitosan in beer, no viable cells of the thermoresistant strain Bacillus megaterium were detected. Nisin, chitosan and hops increased microbiological stability during storage of a local commercial beer inoculated with Lactobacillus plantarum or Pediococcus sp. isolated from wort. Pulsed Electric Field (PEF) (8 kV/cm, 3 pulses) application enhanced antibacterial activity of nisin and hops but not that of chitosan. The results herein obtained suggest that the use of these antimicrobial compounds in isolation or in combination with PEF would be effective to control bacterial contamination during beer production and storage.

Diferentes antimicrobianos naturales disminuyeron la viabilidad de bacterias contaminantes aisladas en etapas críticas del proceso de producción de cerveza. En un extracto de malta, el agregado de 1 mg/ml de quitosano y de 0,3 mg ml de lúpulo permitió reducir la viabilidad de Escherichia coli a 0,7 y 0,1%, respectivamente, al cabo de 2 horas de incubación a 4 °C. El agregado de 0,0002 mg/ml de nisina, 0,1 mg/ml de quitosano o de 0,3 mg/ml de lúpulo inhibió selectivamente (10.000 veces más) el crecimiento de Pediococcus sp. respecto de la levadura de cerveza en un cultivo mixto. El agregado de 0,1 mg/ml de quitosano permitió disminuir la viabilidad de una cepa bacteriana termorresistente, Bacillus megaterium, hasta niveles no detectables. Por otra parte, el agregado de nisina, quitosano y lúpulo aumentó la estabilidad microbiológica durante el almacenamiento de cervezas inoculadas con Lactobacillus plantarum y Pediococcus sp. aislados de mosto de cerveza. La aplicación de campos eléctricos pulsantes (CEP) (3 pulsos de 8kV/cm) aumentó el efecto antimicrobiano de la nisina y del lúpulo, pero no el del quitosano. Los resultados obtenidos indicarían que el uso de antimicrobianos naturales en forma individual o en combinación con CEP puede constituir un procedimiento efectivo para el control de la contaminación bacteriana durante el proceso de elaboración y almacenamiento de la cerveza.

The effects of semiconductor laser irradiation and a high voltage static electric field on small vessel impairment in diabetic rats / 中华物理医学与康复杂志

Objective To study the effects of semiconductor laser irradiation and high voltage static electric fields on small vessel damage in diabetic rats.Methods Fifty healthy male Wistar rats were randomly divided into two groups:8 rats in a normal group and 42 in a diabetic model group.The diabetic models were created by intrape- ritoneal injection of streptozocin.The diabetic model rats were randomly divided into four subgroups:a diabetes group,a semiconductor laser treatment group,a high voltage static electric field treatment group and a comprehensive treatment group receiving combined semiconductor laser and high voltage static electric field exposure.The rats in each treatment group were subjected to the corresponding intervention.After 20 days of treatment,the venous blood, kidney tissue and myocardium tissue of the rats were collected,and the concentrations of blood glucose,insulin,en- dothelin and tissue were detected.Results Compared with the normal group,a significant increase in blood glu- cose and endothelin was observed in the diabetic model group,along with significantly decreased blood insulin and significant small vessel endothelium proliferation in the kidney tissue.Compared with the diabetes group,endothelin levels were significantly lower in all 3 treatment groups,and blood insulin was also higher in the comprehensive treat- ment group.Conclusion There were severe abnormalities in blood glucose,insulin and endothelin as well as mild impairment of small vessel endothelium proliferation in the diabetic rats.Semiconductor laser and high voltage static electric field exposure have a role in treating and preventing these conditions in diabetic rats.