IN-VITRO DISSOLUTION OF CORAL IN PERITONEAL OR FIBROBLAST CELL-CULTURES

Previous studies have shown that in vivo coral resorption involves a b iphasic process. First, the edges oi the coral block become powdery, t hen extracellular fluid and phagocytosis contribute to the dissolution oi the crystals. The authors examined some types of cells that could be involved in phagocytosis, particularly the ability of both dermal f ibroblasts and mouse-resident peritoneal cells to phagocytose and diss olve coral powder ''in vitro'' Radioactive coral was incubated for 24, 48, or 72 hrs with cells in the presence or absence of cytochalasin B (a phagocytic inhibitor) or chloroquine (a lysosomotropic agent). Fur thermore, to specify the role of crystal cell contacts in the solubili zation process, they incubated radioactive coral in conditioned media (obtained from two-day human fibroblastic or macrophagic cell culture in the presence or absence of non-radioactive coral) or at a distance from the cells using culture inserts. Measurements of the radioactivit y in the different supernatants were performed. Transmission electron microscopy was carried out on the cells cultivated in the presence or absence of radioactive coral. The data suggest that both fibroblasts a nd macrophages dissolve the coral, and that the intracellular degradat ion in phagolysosomes is one of the mechanisms explaining coral powder dissolution.