DISSOLUTION OF SHORT AND LONG ROCKWOOL AND GLASSWOOL FIBERS BY MACROPHAGES IN FLOWTHROUGH CELL-CULTURE

Dissolution of MMVF (man-made vitreous fibers) by macrophages has prev iously been studied utilizing cell cultures in wells. A new, more dyna mic method has been developed to explore the effects of macrophages on MMVF dissolution. In this method, the culture medium hows through a m embrane on which the macrophages and fibers are placed. The dissolutio n of short and long rockwool and glasswool fibers was investigated in the present study by macrophages by assessing the dissolution of Si (s ilicon), Fe (iron), and Al (aluminium) from the fibers. Dissolution of these elements usually increased as a function of time. Generally, th e dissolution of elements from the fibers in the flowthrough culture e xceeded that observed with the culture in wells system. The dissolutio n of glasswool fibers was greater in medium than in cell culture, wher eas the opposite was true for rockwool fibers. Dissolution of Si was g reater from glasswool than from rockwool fibers, while the opposite wa s true for Fe and Al. Macrophages that had phagocytized fibers in flow through culture contained Si, and there were also precipitations with Si in the samples. The fibers in the flowthrough culture also exhibite d surface changes such as breakings, pittings, etching, and peeling. T he short rockwool fibers tended to fracture more than short glasswool fibers, while long glasswool fibers were more extensively broken than short glasswool fibers. The results with this new, dynamic, flowthroug h culture method with macrophages demonstrate that this method provide s valuable information on the abilities of macrophages to dissolve MMV F leading to subsequent morphological changes of fibers. (C) 1998 Acad emic Press.