Fig. 8
Cell degeneration events. In a, percentage distribution of apoptotic programmed cell death events (type I—PCD) and a form of cell degeneration with autophagic features. Morphological examples of apoptotic death in cells with 2 c and 8 c DNA content are shown in the inserted fluorescence micrographs (acridine orange staining). In a1 and a2, the arrows indicate chromatin condensation with margination against the nuclear envelope and karyorrhexis events, respectively. In a3 and a4, the arrows indicate nuclear apoptotic-like alterations (shrinkage and nuclear budding). In a3, an example of nuclear fragmentation/micronucleation can be observed in a cell with a DNA content near the 12 c value (arrowhead). In b, the percentages of chromosome aggregates and nuclear fragmentation/micronucleation are shown. The inserted fluorescence micrographs (b1 and b2) show, in a microscopic field (HO 33342-blue fluorescence) (b1), the nuclear positivity to the TUNEL reaction (red fluorescence) (b2), indicating DNA fragmentation in apoptotic nuclei (arrows) and alternative forms of cell death (arrowheads). The individual percentage values were calculated within the subpopulations with different DNA content. The various cellular aspects were evaluated in both controls (PEG-untreated cells) and after PEG treatment. Vinblastine incubation was carried out in both PEG-untreated cells (VBL) and in previously PEG-treated cultures (PEG-VBL). To establish the various cellular aspects, at least 300 cells for each DNA content value were evaluated. The values, which refer to the main cell subpopulation of NIHs culture in the different experimental conditions, represent the mean number of cells ± SEM of triplicate morphological evaluations. The asterisks (*) indicate the values, referred to the different experimental conditions, that are not significantly different (P > 0.05 after Student's t-test) from the control (PEG-untreated cells). Type I PCD values, referring to the 4c and 8c subpopulations, are all significantly different (P < 0.05 after Student's t-test) from those of the 2c subpopulation