Irreversible electroporation is a process, where tissue is exposed to sufficiently intensive pulsed electric field (PEF) treatment with the aim to cause cell death. Irreversible electroporation is used in medicine for ablation (removal) of tissue. The area of tissue ablation is determined by many methods, one of them being staining with 2,3,5-triphenyltetrazolium chloride (TTC). In our research we investigated the influence of different electroporation protocols on the size of the ablation area and how different electroporation protocols and other factors influence the staining of tissue with TTC in areas under the irreversible electroporation threshold.
The experiments were conducted on slices of potato, black radish, zucchini, and melon. For each tissue there were 9 different protocols. We used 3 different voltages – 500 V, 1000 V, and 1500 V. For each of the voltages, we used 3 different pulse shapes: 8 monopolar rectangular pulses, 1 exponentially decreasing pulse, and a combination of the two, i.e. 8 monopolar rectangular pulses followed by 1 exponentially decreasing pulse. The tissue slices were submerged in TTC solution after electroporation. The staining was analysed by computer analysis.
We discovered that the combination of 8 monopolar rectangular pulses and 1 exponential decreasing pulse did not cause a larger area of ablation than 1 exponential decreasing pulse at the same voltage in most cases. We also discovered that in some cases the TTC staining is not evenly distributed across the tissue but gets darker (more intense) in the immediate vicinity of the ablated area. We are unable to definitively identify, based on the experiments conducted, whether this intensely coloured area is due to effect of turgor pressure loss or cell metabolism.
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