Annexin V / PI assay on HMEC and Jurkat cells 8 and 24 Hours after plasma treatment.

<p>Cells were treated for 30 to 120 sec and from 75 to 900 Hz frequency. The administered dose is expressed in J/cm². Flow Cytometry data are analysed on a four quadrant dot plot gated on a region including cells and debris. Propidium iodide (PI) signal is detected in the Phycoerythrine channel, on the Y axis. FITC-labelled Annexin V signal is detected on the X axis. Non-apoptotic, non-necrotic, living cells are located in the lower left quadrant. Results are expressed as median +/- standard deviation. On the right, for each experimental time, a histogram including statistical analyses summarizes cytometry data. Statistical significance: * means p<0.05 when compared with the control; ** means p<0.05 when compared with the immediately lower dose, *** means p<0.05 when compared with the control and the immediately lower dose. On Jurkat cells, 8 hours after treatment, the type of cell death is mainly apoptosis, up to 255 J/cm². Above this dose, the type of cell death is mainly necrosis. At H24, the pattern is non-specific, consistent with late apoptosis or necrosis. Overall the data are consistent with the hypothesis that NPP induces apoptosis on Jurkat cells up to the dose of 255 J/cm². On HMEC, 24 hours after treatment, at 510 J/cm², there is an increase of Annexin V-only positive cells consistent with apoptosis. Otherwise the pattern is mainly necrotic. On HMEC and Jurkat cells, there is a dose effect. To reach a given percentage of dead cells, HMEC cultures need higher doses than Jurkat cells.