Cytotoxicity and DNA-damage in human lung epithelial cells exposed to respirable alpha-quartz.
Occupational exposure to respirable crystalline silica is associated with the development of silicosis, lung cancer and airways diseases. In order to assess cytotoxic effects and direct-oxidative DNA damage induced by short-term exposure to different doses of respirable alpha-quartz (NIST SRM1878a), we conducted a study using A549 cells. The cells were exposed to alpha-quartz at 25, 50, 100 microg/ml for 4 h and analysed by scanning electron microscope (SEM) and LDH release assay for cytotoxic effect evaluation. Cells were also exposed to 10, 25, 50, 100 microg/ml of alpha-quartz for 2 h and 4 h and analysed by Fpg comet test to evaluate direct and oxidative DNA damage. SEM observations of treated cells showed bleb development at lower doses and alterations of microvilli morphology at the highest dose. A slight LDH release was found only at 100 microg/ml. Fpg comet test showed a dose-related oxidative DNA damage in cells exposed for 2 h to quartz. Cells exposed for 4h at the same concentrations showed a dose-related direct DNA damage and the presence of oxidative DNA damage at lower doses. The bleb induction on cell surface evidenced by SEM at lower doses correlates with the presence of oxidative DNA damage at 4 h. The cell surface modifications observed by SEM at 100 microg/ml indicate that high doses of quartz induce more evident cytotoxic effects confirmed by LDH analysis and correlate with the genotoxicity showed by comet assay.
Fanizza
Carla
C
Department of Occupational Hygiene, ISPESL, National Institute for Occupational Safety and Prevention, Via Fontana Candida 1, 00040 Monteporzio Catone, Rome, Italy. carla.fanizza@ispesl.it
Ursini
Cinzia Lucia
CL
Paba
Emilia
E
Ciervo
Aureliano
A
Di Francesco
Arianna
A
Maiello
Raffaele
R
De Simone
Paolo
P
Cavallo
Delia
D
D000336:Aerosols; D002460:Cell Line; D004249:DNA Damage; D004847:Epithelial Cells / Q000187:drug effects* / Q000473:pathology; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008168:Lung / Q000737:chemistry* / Q000187:drug effects* / Q000473:pathology; D008855:Microscopy, Electron, Scanning; D018384:Oxidative Stress; D010316:Particle Size; D011791:Quartz / Q000633:toxicity*; D020545:Respiratory Mucosa / Q000166:cytology* / Q000187:drug effects* / Q000473:pathology
D000336:Aerosols; D011791:Quartz; D007770:L-Lactate Dehydrogenase