title: Influence of silica and carrageenan on spleen colonies and colonies in murine peritoneal cell-coated cellulose acetate membranes.
abstract: Cellulose acetate (CA) discs placed in the peritoneum of mice become coated by a layer of peritoneal cells consisting primarily of macrophages (M). These CAM support the growth of hematopoietic colonies when syngeneic bone marrow cells are injected intraperitoneally. Most of these colonies are granulocytic and are recognizable by their peroxidase reaction. Since silica and carrageenan are known to reduce macrophage function, their effect on CAM granulocyte colony formation was tested. Carrageenan injected intraperitoneally before, concurrently, or after injection of marrow cells markedly reduced colony formation. Silica injected intraperitoneally concurrently or after injection of marrow cells reduced colony formation. Silica injected before marrow cells did not reduce colony formation. CAM produced in one mouse and exposed to carrageenan or silica in situ for 24 h before being transferred to sublethally irradiated recipients and seeded by injection of marrow cells had control levels of granulocytic colonies. Likewise, CAM produced in one mouse, removed, incubated in vitro with carrageenan or silica, carefully rinsed and transferred to sublethally irradiated recipients and seeded with marrow cells were able to support control levels of colony formation. Intravenous injection of silica or carrageenan had no consistent effect on colony formation. Spleen colonies (CFU-S) from marrow cells incubated in vitro with the agents, and given intravenously to lethally irradiated mice, were inhibited by silica, but not by carrageenan. Silica or carrageenan given intravenously to irradiated mice 3 h before or 3 h after intravenous marrow cell injection enhanced subsequent CFU-S formation.
mesh_terms: D000818:Animals; D001202:Ascitic Fluid / Q000166:cytology; D002351:Carrageenan / Q000494:pharmacology*; D002482:Cellulose / Q000031:analogs & derivatives; D003114:Colony-Forming Units Assay; D006410:Hematopoiesis / Q000187:drug effects*; D008264:Macrophages / Q000502:physiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D012822:Silicon Dioxide / Q000494:pharmacology*; D013154:Spleen / Q000166:cytology*; D013997:Time Factors
chemical_list: C005062:acetylcellulose; D012822:Silicon Dioxide; D002351:Carrageenan; D002482:Cellulose