Nanosecond electric pulses cause mitochondrial membrane permeabilization in Jurkat cells

Nanosecond, high-voltage electric pulses (nsEP) induce permeabilization of the plasma membrane and the membranes of cell organelles, leading to various responses in cells including cytochrome c release from mitochondria and caspase activation associated with apoptosis. We report here evidence for nsEP-induced permeabilization of mitochondrial membranes in living cells. Using three different methods with fluorescence indicatorsrhodamine 123 (R123), tetramethyl rhodamine ethyl ester (TMRE), and cobalt-quenched calceinwe have shown that multiple nsEP (five pulses or more, 4?ns duration, 10?MV/m, 1?kHz repetition rate) cause an increase of the inner mitochondrial membrane permeability and an associated loss of mitochondrial membrane potential. These effects could be a consequence of nsEP permeabilization of the inner mitochondrial membrane or the activation of mitochondrial membrane permeability transition pores. Plasma membrane permeabilization (YO-PRO-1 influx) was detected in addition to mitochondrial membrane permeabilization. Bioelectromagnetics 33:257264, 2012. (C) 2011 Wiley Periodicals, Inc.