Fig. 2

Cell volume changes in esophageal cancer cells (line KYSE170) after hypotonic shock. The cell volume and the cell counts were simultaneously measured at 1, 5, 10 and 20 min after hypotonic shock at various osmolarities using a high-resolution flow cytometer (Cell Lab Quanta). When the cells were exposed to mild hypotonicity (×1/2 NaCl, i.e., the isotonic NaCl buffer was diluted twofold with DW), the cell volume initially increased and then decreased gradually to the pre-hypotonic shock level, suggesting that mild hypotonicity could induce regulatory volume decrease. When the cells were exposed to DW, the overall cell volume was smaller than the pre-hypotonic shock volume, suggesting that almost all of the cells had broken into fragments. Exposure to isotonic NaCl buffer did not cause any significant changes in cell volume within 20 min (data not shown)