Diffuse, non-polar electropermeabilization and reduced propidium uptake distinguish the effect of nanosecond electric pulses.
Diffuse, non-polar electropermeabilization and reduced propidium uptake distinguish the effect of nanosecond electric pulses.
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DOI：
10.1016/j.bbamem.2015.06.018
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发表时间：
2015-10
期刊：
影响因子：
--
通讯作者：
Pakhomov AG
中科院分区：
文献类型：
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作者：
Semenov I;Zemlin C;Pakhomova ON;Xiao S;Pakhomov AG
比较了10 ns和4 ms电脉冲(nsEP和msEP)对大鼠胚胎心肌细胞钙激活和膜电穿孔的影响。触发钙瞬变的最低电场nsEP(36kV/cm)预期高于msEP(0.09kV/cm)，但各自的剂量相似(190和460mJ/g)。在更高的强度下，两种刺激都会在静止的细胞中引发长时间的放电。电压门控性钙通道阻断和钙库耗竭的细胞在63kV/cm(NsEP)或0.14kV/cm(MsEP)时出现基础钙水平升高，可作为电穿孔阈值。尽管脉冲持续时间相差400,000倍，但msEP和nsEP的这些电场值都是刺激阈值的150-230%。对于类似水平的电穿孔钙摄取，msEP对丙酸的摄取至少是nsEP的10倍，这表明更大的毛孔的产量增加。MsEP的电穿孔使细胞内的钙离子在面对电极的电极上突然局部地进入细胞内，然后缓慢地向细胞中心扩散。与之形成鲜明对比的是，nsEP诱发了一种“超电穿孔”模式，即缓慢但空间均匀的钙离子进入。因此，nsEP和msEP具有相似的剂量效率，但在电孔的大小和位置上存在巨大差异。
Ca2+ activation and membrane electroporation by 10-ns and 4-ms electric pulses (nsEP and msEP) were compared in rat embryonic cardiomyocytes. The lowest electric field which triggered Ca2+ transients was expectedly higher for nsEP (36 kV/cm) than for msEP (0.09 kV/cm) but the respective doses were similar (190 and 460 mJ/g). At higher intensities, both stimuli triggered prolonged firing in quiescent cells. An increase of basal Ca2+ level by >10 nM in cells with blocked voltage-gated Ca2+ channels and depleted Ca2+ depot occurred at 63 kV/cm (nsEP) or 0.14 kV/cm (msEP) and was regarded as electroporation threshold. These electric field values were at 150–230% of stimulation thresholds for both msEP and nsEP, notwithstanding a 400,000-fold difference in pulse duration. For comparable levels of electroporative Ca2+ uptake, msEP caused at least 10-fold greater uptake of propidium than nsEP, suggesting increased yield of larger pores. Electroporation by msEP started Ca2+ entry abruptly and locally at the electrode-facing poles of cell, followed by a slow diffusion to the center. In a stark contrast, nsEP evoked a “supra-electroporation” pattern of slower but spatially uniform Ca2+ entry. Thus nsEP and msEP had comparable dose efficiency, but differed profoundly in the size and localization of electropores.