CYTOLYTIC ACTION OF CORTICOSTEROIDS ON THYMUS AND LYMPHOMA CELLS IN VITRO

Abstract

Mouse and rat thymus cells can be maintained in good condition for up to 24 hours in tissue culture medium (Fischer's or 199) with serum or serum proteins, when aerated and incubated at 38 °C in stoppered tubes. Addition of corticosteroids produces cytolytic effects in nearly all cells, which are highly specific for those compounds having an 11β-hydroxyl group. Maximum effect occurs at concentrations of cortisol 0.27 μM, of dexamethasone 0.02 μM. Electron microscopy shows marked alteration at 2 hours with nuclear edema and disappearance of the normal chromatin pattern in treated cells, progressing to maximum at about 8 hours with disruption of nuclear and cell membranes. Steroid-sensitive mouse lymphosarcoma P1798 cells show similar changes, whereas those of the steroid-resistant subline do not. To demonstrate this action of corticosteroids at concentrations that are significant physiologically, the major difficulty is maintaining the cells in satisfactory condition. It is concluded that this effect of steroids is manifested only in cells that are intact and metabolically active, and might be independent of many other known biochemical changes produced by corticosteroids.