Effects of Total-Body X-Irradiation on Peritoneal Cells of Mice

Abstract

Abstract : Peritoneal cells of normal and irradiated LAF1 mice which had not been pretreated with peritoneal irritants were studied by phase-contrast microscopy and in stained smears. The average number of leucocytes recovered per normal mouse was 7.4 million. Approximately 95% of the cells were mononuclear; of these, macrophages comprised 29% (2.2 million), small and medium lymphocytes 71% (as determined by phase-contrast). One day after whole-body exposure to 690 R (LD30/30) or 720 R (LD50/30) the mean leucocyte count was 3.4 million, macrophages accounted for 65% (2.2 million) of the cells. From 3 to 21 days postirradiation, cell counts gradually decreased further to 1.5 million. Macrophages decreased at the same rate; they constututed approximately 79% of the cells during this period. Thereafter, the number of leucocytes increased and reached normal levels by the 12th week postirradiation. When suspensions of viable Escherichia coli or Staphylococcus aureus were injected 30 minutes before sacrifice, the macrophages of both normal and irradiated mice contained large numbers of microorganisms. Thirty minutes after injection of bacteria or E. coli lipopolysacchride (10 micrograms) into normal mice, the number of cells in peritoneal washings was not altered. However, after injection of these agents into irradiated mice, total cell counts were significantly lower than in uninjected or diluent-injected mice.