Fig. 4

Cell mononuclearity and multinuclearity related to the DNA content. Phase contrast (a) and acridine orange (AO) fluorescence (b–f) micrographs of PEG-treated NIHs cells. In a, the morphological aspect of the culture, with a multinucleated giant cell. In b, c, d, and f, AO staining, performed according to a standard protocol, allowed us to observe green nuclear DNA and red cytoplasmic RNA fluorescence. In all fluorescence micrographs, the value of the DNA content of polyploid cells is reported. In d, arrowheads indicate micronuclei in the cytoplasm of a 16c tetranucleated cell, while in e, the punctuate red fluorescence of acidic vesicles in the cytoplasm (after the use of dilute AO solution) is shown. Scale bars: 10 µm