Modificational changes in function and morphology of cultured macrophages by geraniin

Treatment of peritoneal macrophages with geraniin, isolated from Geranium funbergii, markedly induced the phagocytosis of living yeasts. Marked increases in phagocytosis and acid phosphatase activity in macrophage lysates were observed 24 hr after the beginning of geraniin treatment. As observed by electron microscopy, macrophages that had been treated for 24 hr with geraniin had a markedly thickened surface layer which was positive to ruthenium red, compared to the control cells. In addition, geraniin treatment of macrophages appeared to induce remarkably large mitochondria, more coated pits and prominent lysosomal granules. In conclusion, the stimulation of phagocytosis and acid phosphatase activity of macrophages by geraniin treatment may involve alterations of the plasma membrane and cytoplasmic reorganization.