Nesin Olena M, Pakhomova Olga N, Xiao Shu, Pakhomov Andrei G
Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA 23508, USA.
Biochim Biophys Acta. 2011 Mar;1808(3):792-801. doi: 10.1016/j.bbamem.2010.12.012. Epub 2010 Dec 20.
Intense nanosecond-duration electric pulses (nsEP) open stable nanopores in the cell membrane, followed by cell volume changes due to water uptake or expulsion, as regulated by the osmolality balance of pore-impermeable solutes inside and outside the cell. The size of pores opened by either fifty 60-ns EP (13 kV/cm) or five, 600-ns EP (6 kV/cm) in GH3 cells was estimated by isoosmotic replacement of bath NaCl with polyethylene glycols and sugars. Such replacement reduced cell swelling or resulted in transient or sustained cell shrinking in response to EP. depending on the availability of pores permeable to the test solute. Unexpectedly, solute substitutions showed that for the same integral area of pores opened by 60- and 600-ns treatments (as estimated by cell volume changes), the pore sizes were similar. However, the 600-ns exposure triggered significantly higher cell uptake of propidium. We concluded that 600-ns EP opened a greater number of larger (propidium-permeable pores), but the fraction of the larger pores in the entire pore population was insufficient to contribute to cell volume changes. For both the 60- and 600-ns exposures, cell volume changes were determined by pores smaller than 0.9 nm in diameter; however, the diameter increased with increasing the nsEP intensity.
高强度纳秒级电脉冲（nsEP）可在细胞膜上打开稳定的纳米孔，随后由于细胞内外不可渗透溶质的渗透压平衡调节，细胞会因吸水或排水而发生体积变化。通过用聚乙二醇和糖类等渗替代浴液中的氯化钠，估算了在GH3细胞中由五十个60纳秒电脉冲（13 kV/cm）或五个600纳秒电脉冲（6 kV/cm）打开的孔的大小。这种替代减少了细胞肿胀，或导致细胞对电脉冲产生短暂或持续的收缩，这取决于对测试溶质可渗透的孔的情况。出乎意料的是，溶质替代表明，对于由60纳秒和600纳秒处理打开的相同积分面积的孔（通过细胞体积变化估算），孔径相似。然而，600纳秒的暴露引发了更高的碘化丙啶细胞摄取。我们得出结论，600纳秒的电脉冲打开了更多更大的（可透过碘化丙啶的孔），但在整个孔群体中较大孔的比例不足以导致细胞体积变化。对于60纳秒和600纳秒的暴露，细胞体积变化由直径小于0.9纳米的孔决定；然而，随着纳秒级电脉冲强度的增加，直径会增大。
