ABSTRACT
The aim of this study was to elucidate the effects of hyperthermic treatment on cell morphology and the cytoskeleton in CHO AA8 cell line. The effects of exposure to elevated temperature were analyzed in CHO AA8 cell line by fluorescence microscopy and flow cytometry. The 30 min, at 44.5 degrees C heat shock treatment resulted in the collapse of microtubules (MTs) and microfilaments (MFs) around the nucleus followed by their recovery 24 h after heating. The initial collapse of these cytoskeletal systems, observed 15 min after treatment, was accompanied by the appearance of cells with reduction of volume, shrunken cytoplasm and condensed chromatin. 24 h afterwards, there was the increase in the number of cells with restored and extended MT and MF cytoskeletons. Most of them were larger in size compared to the control cells and had multiple nuclei. 48 h after heat shock the highest number of the giant cells with alternation in nuclear morphology was seen. Flow cytometry analysis revealed the increase in the number of cells with externalized phosphatidylserine 24 h and 48 h after hyperthermic treatment. These results suggest that following heat shock, CHO AA8 cells undergo mitotic catastrophe that presumably represents one of the events resulting in apoptosis.
