Carbon in intimate contact with quartz reduces the biological activity of crystalline silica dusts.
To evaluate the effect of carbonaceous materials on the pathogenic activity of quartz dusts, mixtures of carbon soot (1 and 10%) and quartz (Min-U-Sil) were prepared and then milled so to attain an intimate association of carbon and the quartz surface. Both cellular and cell-free tests show that carbon associated to quartz completely inhibits the typical free radical generation of quartz dusts (through Fenton activity and homolytic cleavage of a C-H bond) and suppresses the oxidative stress and inflammation induced by quartz alone on MH-S murine macrophage cells (lipid peroxidation, nitric oxide release, and tumor necrosis factor-α synthesis). The cytotoxic response to quartz is also largely reduced. An extremely pure quartz milled with 10% of soot showed inactivating effects on the adverse reactions to quartz similar to Min-U-Sil quartz. None of these effects takes place when the same experiments are carried out with mechanically mixed samples, which suggests that carbon acts not just as a radical quencher but because of its association to the quartz surface.
"G. Scansetti" Interdepartmental Center for Studies on Asbestos and Other Toxic Particulates, University of Torino , Italy.
Mara
M
Ghiazza
Maura
M
Tomatis
Sophie
S
Doublier
Francesca
F
Grendene
Elena
E
Gazzano
Dario
D
Ghigo
Bice
B
Fubini
D000818:Animals; D002244:Carbon / Q000737:chemistry*; D002460:Cell Line; D004391:Dust / Q000032:analysis*; D017665:Hydroxyl Radical / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D011791:Quartz / Q000737:chemistry* / Q000633:toxicity; D012822:Silicon Dioxide / Q000737:chemistry* / Q000633:toxicity; D013499:Surface Properties; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D004391:Dust; D014409:Tumor Necrosis Factor-alpha; D011791:Quartz; D009569:Nitric Oxide; D017665:Hydroxyl Radical; D002244:Carbon; D012822:Silicon Dioxide; D019001:Nitric Oxide Synthase