Cytosolic Free Clcium Fluctuation Mediates Phagocytosis in Mouse Macrophages

Abstract : Cytosolic free calcium ([Ca2+]i ) change was assessed in single adherent mouse macrophages during phagocytosis for dead cells. To determine visualizing Ca2+ change during phagocytosis and indirectly show phagocytic function of macrophages to dead cells, intracellular [Ca2+]i of macrophages were loaded with the fluorescent dye Fluo-3/AM and dead cells were labeled with Propidium Iodide(PI), we examined images pattern of the fluorescence intensity in macrophages of containing dead cells. A discharge of calcium was verified by confocal scanning laser microscopy (CSLM). In lacking Ca2+ medium, upon contact with dead cells, rapid assemble and increase of [Ca2+]i was observed in macrophage. Intracellular [Ca2+]i rose to a higher level during initial phagosome formation. After a rapid rise, free Ca2+was decreased in digestion of phagocytotic vesicle; there-after the [Ca2+]i returned to the baseline. Our study directly indicates that accompany presenting and disappearing of dead cell of red fluorescence in the phagosomal vesicle, a series of images pattern of [Ca2+]i change can be really exhibited in macrophages. It is suggest that [Ca2+]i fluctuation has a certainty in macrophages during the phagocytosis.