title: Silica particle size and shape: in vitro effects on extracellular matrix metabolism and viability of human bronchial epithelial cells.
abstract: Crystal micro-morphology and dimension of silica particles could be responsible for the high prevalence of silicosis as recently found among goldsmiths. In the present study we investigated two samples of silica particles with different surface sizes and shapes for their capacity to induce changes in ECM component production. In addition we investigated if their different effects could be related to cytotoxicity and apoptotic effects. Human bronchial epithelial cells were cultured with or without a sample of Silica used for casting gold jewellery, named in our experiments Silica P or a commercial sample of Silica with different physical and chemical properties, named in our experiments Silica F. After 48 h of exposure PCR analysis determined levels of several matrix components. As induction of the apoptosis cascade, annexin assay, caspase 3 activity and cellular cytoxicity by MTT assay were assayed. Silica F promoted fibronectin, MMP12, tenascin C and Integrins b5 gene expressions more than Silica P. Silica P stimulated more TGF&#223;1 and its TGF&#223;R1 receptor than Silica F. Cytotoxic effects were induced by the two samples of Silica. On the contrary, no alteration in classic apoptotic marker protein expression was observed in presence of either Silica F or Silica P, suggesting silica particles affect ECM production and metalloproteases through a mechanism that does not involve apoptotic activation. Different Silica micromorphology and TGF&#223; signal pathway are linked to lung fibrotic effects but the potential role Silica in apoptotic and toxic reaction remains to be ascertained.
authors.affiliation: Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Perugia, Italy. bodo@unipg.it
authors.forename: M
authors.initials: M
authors.lastname: Bodo
authors.forename: C
authors.initials: C
authors.lastname: Lilli
authors.forename: M
authors.initials: M
authors.lastname: Calvitti
authors.forename: E
authors.initials: E
authors.lastname: Rosati
authors.forename: G
authors.initials: G
authors.lastname: Luca
authors.forename: A
authors.initials: A
authors.lastname: Lumare
authors.forename: A
authors.initials: A
authors.lastname: Gambelunghe
authors.forename: N
authors.initials: N
authors.lastname: Murgia
authors.forename: G
authors.initials: G
authors.lastname: Muzi
authors.forename: C
authors.initials: C
authors.lastname: Bellucci
mesh_terms: D001980:Bronchi / Q000166:cytology / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005353:Fibronectins / Q000235:genetics; D006801:Humans; D039482:Integrin alpha5 / Q000235:genetics; D053508:Matrix Metalloproteinase 12 / Q000235:genetics; D053509:Matrix Metalloproteinase 13 / Q000235:genetics; D010316:Particle Size; D012822:Silicon Dioxide / Q000633:toxicity*
chemical_list: D016326:Extracellular Matrix Proteins; D005353:Fibronectins; D039482:Integrin alpha5; D012822:Silicon Dioxide; D053509:Matrix Metalloproteinase 13; D053508:Matrix Metalloproteinase 12