Cell Volume Reduction Associated with Interphase Death in Rat Thymocytes

Abstract

Correlation of interphase death with cell volume reduction in rat thymocytes was examined using an automated cell size distribution analyzer. After x irradiation from 50 to 2000 r in vitro, cell suspension were incubated at 37/sup 0/C for 4 h. Measurement of cell size distribution during and after incubation demonstrated that the irradiated thymocyte suspension consisted of two discrete subpopulations, one of normal size and the other of smaller size. The number of smaller cells increased parallel to a rise in dead(erythrosine B stained) cell counts with incubation time and radiation dose, suggesting that smaller cells might correspond to dead thymocytes. This was confirmed by examining a centrifugally separated dead-cell population, which had a size distribution curve similar to that of the smaller cells. The possibility that small-cell counts could be used as a new criterion for interphase death is discussed.