IN-VITRO CHARACTERIZATION OF RADIOTHERAPY-INDUCED MORPHONUCLEAR MODIFICATIONS ON CHEMOSENSITIVE AS OPPOSED TO CHEMORESISTANT NEOPLASTIC-CELLS

Purpose: We describe by means of digital cell image analysis the influ ence of X-ray radiation on three in vitro cultured cell lines for whic h we set up chemosensitive and chemoresistant variants. Methods and Ma terials: The three cell lines correspond to the MXT mouse mammary and the T24 and J82 neoplastic human bladder cells. The digital cell image analysis was carried out by computing morphometric (nuclear size), de nsitometric (proportion of cells in the G2 cell cycle phase), and text ural features (chromatin pattern characteristics) on Feulgen-stained n uclei. Results: The results show that such digital cell image analyses make it possible to monitor radiotherapy-induced effects on these mor phonuclear characteristics accurately. X-ray radiotherapy induces a do se-dependent increase in the proportion of cells in the G2 phase of th e cell cycle along with a decrease in the overall chromatin condensati on level. These two concomitant phenomena lead to a marked radiotherap y-induced increase in nuclear size. We also observed that radiotherapy -induced effects at the morphonuclear level are not only highly specif ic to the cell type analyzed, that is MXT mouse mammary or J82 or T24 human bladder carcinoma cells, but also to the fact that the cells are either chemosensitive or chemoresistant. Conclusion: The digital cell image analyses of Feulgen-stained nuclei is helpful in monitoring the irradiation-induced morphonuclear modifications.