The nuclear envelope is a physiological barrier to electrogene transfer. To understand different mechanisms of the nuclear entry for electrotransfected plasmid DNA (pDNA), the current study investigated how manipulation of the mechanisms could affect electrotransfection efficiency (eTE), transgene expression level (EL), and cell viability. In the investigation, cells were first synchronized at G2-M phase prior to electrotransfection so that the nuclear envelope breakdown (NEBD) occurred before pDNA entered the cells. The NEBD significantly increased the eTE and the EL while the cell viability was not compromised. In the second experiment, the cells were treated with a nuclear pore dilating agent (i.e., trans-1,2-cyclohexanediol). The treatment could increase the EL, but had only minor effects on eTE. Furthermore, the treatment was cytotoxic, compared to the cell synchronization. In the third experiment, a nuclear targeting sequence (i.e., SV40) was incorporated into the pDNA prior to electrotransfection. The incorporation was more effective than the cell synchronization for enhancing the EL but not the eTE, and the effectiveness was cell-type dependent. Taken together, the data described above suggested that synchronization of the NEBD could be a practical approach to improving electrogene transfer in all dividing cells.

核被膜是电基因转移的生理屏障。为了了解电转染质粒DNA（pDNA）进入核的不同机制，当前的研究调查了对该机制的操纵如何影响电转染效率（eTE），转基因表达水平（EL）和细胞生存力。在研究中，首先在电转染之前使细胞在G2-M期同步，以使核被膜破裂（NEBD）在pDNA进入细胞之前发生。NEBD显着增加了eTE和EL，而细胞活力并未受到损害。在第二个实验中，将细胞用核孔扩张剂（即反式1，2-环己二醇）处理。该处理可以提高EL，但对eTE的影响很小。此外，这种疗法具有细胞毒性，与单元同步相比。在第三个实验中，在电转染前将核靶向序列（即SV40）整合到pDNA中。结合比细胞同步更有效地增强了EL，但不增强eTE，并且有效性取决于细胞类型。综上所述，上述数据表明，NEBD的同步可能是改善所有分裂细胞中电基因转移的实用方法。