4.4. May-Grunwald Giemsa staining

The wells with PFA-fixed cells were washed with phosphate-buffered saline (PBS), and stained with 200 μL of May-Grunwald dye for 5 min. Then 1 ml of PBS was added to the wells without May-Grunwald dye removal and the cells were stained for additional 15 min in the diluted May-Grunwald solution. Afterwards the wells were washed 3 times with distilled water, stained for 1 h with 1 ml of Giemsa stain (diluted 1:10 in PBS), washed with distilled water again and let dry. All procedures were performed at room temperature. The samples were observed and photographed using the Axio Imager microscope (Zeiss). Five random fields of view were captured for each sample.