Increased mutant frequency by carbon black, but not quartz, in the lacZ and cII transgenes of muta^™mouse lung epithelial cells

Abstract

Carbon black and quartz are relatively inert solid particulate materials that are carcinogenic in laboratory animals. Quartz is a human carcinogen, whereas data on carbon black are contradictory, and there are few data on mammalian mutagenesis. We determined the mutant frequency following eight repeated 72-hr incubations with 75 mug/ml carbon black (Printex 90) or 100 mug/ml quartz (SRM1878a) particles in the FE1 Muta Mouse lung epithelial cell line. For carbon black exposed cells, the mutant frequency was 1.40-fold (95% CI: 1.22-1.58) for cII and 1.23-fold (95% CI: 1.10-1.37) for lacZ compared with identically passaged untreated cells. Quartz did not significantly affect the mutant frequency. Carbon black also induced DNA strand breaks (P = 0.02) and oxidized purines (P = 0.008), as measured by the Comet assay. Quartz induced marginally more oxidized purines, but no change in strand breaks. We detected five (phenanthrene, flouranthene, pyrene, benzo[a]anthracene, and chrysene) of the 16 EPA priority polycyclic aromatic hydrocarbons (PAHs) in an extract of carbon black. The detected PAHs are only weakly mutagenic compared with benzo[a]pyrene, and were present in very low amounts. In conclusion, carbon black was weakly mutagenic in vitro at the cII and lacZ loci. It also induced DNA strand breaks and oxidized DNA bases. More studies are essential for understanding the biological significance of these findings, and clearly documenting DNA sequence changes. The results do not necessarily imply that other carbonaceous nano materials are genotoxic.

Genotoxicity investigations on nanomaterials

“…The most frequently used of these tests (actually the overall most frequently used genotoxicity test used for nanomaterials) was the Comet assay: 19 studies, 14 with positive outcome, the latter on the following materials (all in vitro except where stated): fullerenes (Dhawan et al 2006), SWCNT (Kisin et al 2007), cobalt chrome alloy (Papageorgiou et al 2007), TiO 2 (Wang et al 2007a;Gurr et al 2005;Nakagawa et al 1997;Dunford et al 1997 (Mroz et al 2008;Jacobsen et al 2007), diesel exhaust particles (in vitro and ex vivo; Dybdahl et al 2004), general traffic vehicle exhaust (ex vivo; Vinzents et al 2005), urban and rural air pollution (ex vivo; Avogbe et al 2005), and urban air particles of defined size ranges (ex vivo; Bräuner et al 2007). The Comet assays with negative outcome were performed on the following materials (all in vitro except where stated): Maghemite (nano-cFe 2 O 3 ) coated with DMSA, an organic molecule composed of two carboxylate and two thiolated functions (''NmDMSA'') resulting in a negative surface charge barrier to prevent aggregation and possibly responsible for the negative outcome of the Comet assay (Auffan et al 2006), TiO 2 (Nakagawa et al 1997), Carbon Black (Zhong et al 1997), SiO 2 (Wang et al 2007b, c) and vehicle exhaust (ex vivo) (no increase in DNA strand breaks as determined by Comet assay, but oxidative DNA damage in terms of FPG-sensitive sites; Vinzents et al 2005).…”

“…Five mammalian gene mutation assays were positive (while 2 were negative). The positive mammalian gene mutation assays were performed on the following materials: SiO 2 (Wang et al 2007b, c), TiO 2 (Wang et al 2007a), MWCNT (Zhu et al 2007), Carbon Black (Jacobsen et al 2007;Driscoll et al 1997), all studies in vitro except the last study that was ex vivo and in vitro. Two mammalian gene mutation tests were negative, one in vitro on TiO 2 (Nakagawa et al 1997), one ex vivo (cII mutation frequency in lung tissue of transgenic Muta TM Mice exposed by inhalation to diesel exhaust particles; Dybdahl et al 2004).…”

Particulates and Oxidative Stress

“…However, C 60 fullerenes directly oxidize thiobarbituric acid, indicating that increased TBARS in cell cultures may be a methodological artifact that is not indicative of lipid peroxidation (Lyon et al, 2008 ). Studies on carbon black have provided mixed results with some showing an unaltered level of 8 -isoprostanes (Beck -Speier et al, 2005 ), whereas others report an increase in MDA and oxidatively damaged DNA lesions (Jacobsen et al, 2007 ;Yang et al, 2008 ). Exposure to TiO 2 in cell cultures has yielded contradictory effects on DNA damage (Wamer et al, 1997 ;Gurr et al, 2005 ;Bhattacharya et al, 2008Bhattacharya et al, , 2009Karlsson et al, 2008b ;Vevers and Jha, 2008 ) and only one positive effect in terms of increased TBARS detected with an unreliable spectrophotometric assay (Gurr et al, 2005 ).…”

Verruca localization predominately in black tattoo ink: a retrospective case series

“…6 In fact, black ink contains polycyclic aromatic hydrocarbons that produce reactive oxygen species (ROS) capable of damaging cellular structures by membrane lipid oxidation after exposure to ultraviolet radiation. 7 Furthermore, black ink contains carbon black which is associated with inflammation and mutations following exposure at sub-cytotoxic levels by producing ROS. 7 Lastly, laser diffraction reveals that black ink is composed of almost pure nanoparticles, which are connected to greater ROS production than the larger particles found in coloured ink.…”

“…7 Furthermore, black ink contains carbon black which is associated with inflammation and mutations following exposure at sub-cytotoxic levels by producing ROS. 7 Lastly, laser diffraction reveals that black ink is composed of almost pure nanoparticles, which are connected to greater ROS production than the larger particles found in coloured ink. 8,9 Generalizability is limited by the small sample size of this study and our inability to obtain the specific dyes injected into these patients.…”