Low dose effects of fibrous and non-fibrous mineral dusts on the proliferation of mammalian cells in vitro.
This report presents preliminary results of studies on the growth stimulating properties of mineral dusts. The studies were carried out with Syrian hamster diploid embryonic fibroblasts and Chinese hamster fibroblasts, line B14F28. Toxicity testing was done by the determination of the plating efficiency as a measure of growth and viability. The following dusts were used: the modified UICC asbestos fibres amosite, (AFF) crocidolite (KFF), chrysotile (KFF): in addition glass fibre (GFF), corundum and quartz DQ12. Concentrations > 2 microg/cm2 of AFF, CFF, KFF and GFF depressed the plating efficiency of B14F28 cells in a dose-dependent manner, but all of the fibres and corundum increased colony sizes at concentrations of 0.16-0.33 microg/cm2, in the case of corundum, AFF, KFF, and CFF also at up to 0.66 or 1.32 microg/cm2. DQ12 did not enhance colony growth. The stimulation of proliferation could be demonstrated both in terms of colony size (diameter) and cell numbers. The factor(s) responsible for proliferation stimulation reside in the supernatant, since the medium of dust-treated cell cultures was able to stimulate colony growth after removal of the dusts by filtration. The results indicate the induction of growth factors (cytokines) by low concentrations of the mineral dusts. Experiments concerning the effect of dusts on embryonic golden hamster fibroblasts yielded similar results. The plating efficiency was inhibited by concentrations of GFF and CFF > 0.25 microg cm2 and by AFF, KFF, GFF and corundum at concentrations > 5 microg/cm2, but colony counts were significantly increased by AFF, KFF and corundum at concentrations of 0.25-3 microg/cm2. This biological reaction which was observed in different cell types appears to be especially relevant in the context of environmental exposure where low dust concentrations prevail.
Fischer
A B
AB
Institut of Hygiene and Environmental Medicine, Justus-Liebig-University Giessen, Germany.
Kaw
J L
JL
Diemer
K
K
Eikmann
T
T
D000818:Animals; D001194:Asbestos / Q000737:chemistry / Q000633:toxicity; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004305:Dose-Response Relationship, Drug; D004391:Dust; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects*; D008647:Mesocricetus; D008903:Minerals / Q000737:chemistry / Q000633:toxicity*; D010529:Peritoneal Cavity / Q000166:cytology; D013268:Stimulation, Chemical
D004391:Dust; D008903:Minerals; D001194:Asbestos