Possible New Approach to the Evaluation of Radiation Injury of Bone Marrow

Abstract

IT is well established that injury to bone marrow plays a main part in death from radiation. Fluorescence microscopy with acridine orange was explored by Meisel et al.¹ as a technique for evaluating such injury in cell populations. With the same technique Breivis² also quantified cellular damage induced in rat marrow by chloroethylamines and X-rays. This technique enabled them to determine the number of damaged cells in the marrow samples after X-irradiation or chemical treatment. Their approach, however, does not take into consideration the fact that killed cells are rapidly disposed of by the body. We have recently explored the problem of evaluating radiation injury of the bone marrow, using three different approaches: (1) analysis of the changes in the distribution of cellular dry mass by interference microscopy^3,4; (2) analysis of the changes in distribution of cell size with the Coulter counter⁵; and (3) analysis of the changes in the ability of the cells to survive attacks from cytotoxic agents in dye exclusion tests. The results from the studies of changes in cellular dry mass and cell size were published previously^3–5. The investigation of changes in ability to survive cytotoxic agents is reported here, and suggests that cells killed by radiation disappear rapidly from the cell population. This can be estimated indirectly with cytotoxic dyes or by the combination of a non-toxic dye and a cytotoxic agent.