Evaluation of Cell Death in EB V-Transformed Lymphocytes Using Agarose Gel Electrophoresis, Light Microscopy and Electron MicroscopyI. Induction of Classic Apoptosis by the Bile Salt, Sodium Deoxycholate

AbstractIn this study, we examined the effect of different concentrations of sodium deoxycholate (NaDOC), a secondary bile salt. on an Epstein-Barn virus transformed human lymphoid cell line (NC-37). We found that NaDOC induces classic apoptosis in a dose-dependent manner at 0.1-0.4 mM doses. and necrosis at much higher concentrations (0.8-3.1 mM). This is the first demonstration that a bile salt can induce apoptosis in any cell type. The mode of cell death was determined using morphologic methods (light and electron microscopy) as the gold standard. Standard agarose gel electrophoretic techniques were applied to identify the “ladder” of DNA fragments that have ken associated with apoptosis in certain cell types. Although DNA fragmentation was observed during the apoptotic death of NC-37 cells, we were not able to identify a “ladder” pattern of fragmentation. Two other types of cells, however, that previously have been reported to display a characteristic “ladder” pattern of DNA fragmentation, glucocorticoid-treated WEH17.2 cells and isolated human neutrophils. did display the “ladder” pattern. This study emphasizes the need to examine morphology when identifying the mode of cell death induced by a new agent.Key Words: bile saltapoptosislymphocytegel electrophoresiselectron microscopyDNA degradation