Radioprotection of mice with interleukin-1: relationship to the number of spleen colony-forming units.
Compared to saline-injected mice 9 days after 6.5 Gy irradiation, there were twofold more Day 8 spleen colony-forming units (CFU-S) per femur and per spleen from B6D2F1 mice administered a radioprotective dose of human recombinant interleukin-1-alpha (rIL-1) 20 h prior to their irradiation. Studies in the present report compared the numbers of CFU-S in nonirradiated mice 20 h after saline or rIL-1 injection. Prior to irradiation, the number of Day 8 CFU-S was not significantly different in the bone marrow or spleens from saline-injected mice and rIL-1-injected mice. Also, in the bone marrow, the number of Day 12 CFU-S was similar for both groups of mice. Similar seeding efficiencies for CFU-S and percentage of CFU-S in S phase of the cell cycle provided further evidence that rIL-1 injection did not increase the number of CFU-S prior to irradiation. In a marrow repopulation assay, cellularity as well as the number of erythroid colony-forming units, erythroid burst-forming units, and granulocyte-macrophage colony-forming cells per femur of lethally irradiated mice were not increased in recipient mice of donor cells from rIL-1-injected mice. These results demonstrated that a twofold increase in the number of CFU-S at the time of irradiation was not necessary for the earlier recovery of CFU-S observed in mice irradiated with sublethal doses of radiation 20 h after rIL-1 injection.
Schwartz
G N
GN
Transplantation Laboratory, American Red Cross, Rockville, Maryland 20855.
Patchen
M L
ML
Neta
R
R
MacVittie
T J
TJ
D000818:Animals; D003037:Cobalt Radioisotopes; D003114:Colony-Forming Units Assay; D005260:Female; D005720:Gamma Rays; D007375:Interleukin-1 / Q000627:therapeutic use*; D051379:Mice; D011833:Radiation Injuries, Experimental / Q000517:prevention & control*; D011837:Radiation-Protective Agents / Q000627:therapeutic use*; D011994:Recombinant Proteins; D013154:Spleen / Q000166:cytology*
D003037:Cobalt Radioisotopes; D007375:Interleukin-1; D011837:Radiation-Protective Agents; D011994:Recombinant Proteins