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Lung inflammation and lack of genotoxicity in the comet and micronucleus assays of industrial multiwalled carbon nanotubes Graphistrength(©) C100 after a 90-day nose-only inhalation exposure of rats.

Pothmann D, Simar S, Schuler D, Dony E, Gaering S, Le Net JL, Okazaki Y, Chabagno JM, Bessibes C, Beausoleil J, Nesslany F, Régnier JF - Part Fibre Toxicol (2015)

Bottom Line: Graphistrength (©) C100 multiwalled carbon nanotubes (MWCNT) provide superior electrical and mechanical properties for various applications.The evaluation of the intrinsic hazard properties of Graphistrength(©) C100 is an essential step for safe use.Therefore, Graphistrength (©) C100 appears of low concern in term of local and systemic genotoxicity and a No-Observed Adverse Effect Concentration (NOAEC) of 0.25 mg/m(3) (0.28 mg/m(3) as actual concentration) was established for the repeated-dose toxicity.

View Article: PubMed Central - PubMed

Affiliation: Harlan Laboratories Ltd, Zelgliweg 1, 4452, Itingen, Switzerland. Daniela.pothmann@gmx.de.

ABSTRACT

Background: Graphistrength (©) C100 multiwalled carbon nanotubes (MWCNT) provide superior electrical and mechanical properties for various applications. The evaluation of the intrinsic hazard properties of Graphistrength(©) C100 is an essential step for safe use. A general feature of multiwalled carbon nanotubes after inhalation or intratracheal exposures is the induction of an inflammatory reaction in the lungs sometimes associated with local genotoxic effects.

Methods: After investigating different parameters for the aerosol generation and performing a 5-day inhalation range finding study, male and female Wistar rats were exposed nose-only for 90 days to target concentrations of 0.05, 0.25 and 5.0 mg/m(3) air of Graphistrength (©) C100 and sacrificed 24 h and 90 days after the last exposure. Broncho-alveolar lavage fluid (BALF) was also collected and analyzed for inflammatory parameters. Twenty-four hours post-exposure, chromosomal aberrations in the bone marrow cells were evaluated by the micronucleus test and DNA damages in the lung, kidney and liver cells by both the standard and the human 8-oxoguanine DNA N-glycosylase 1 (hOGG1)-modified comet assay. All studies were performed according to the OECD test guidelines.

Results: An inflammatory lung reaction and the release of inflammatory factors in the BALF were observed in all rats exposed to 5.0 mg/m(3), associated with changes in the differential white blood cells counts. The slight changes in BALF parameters at 0.25 mg/m(3) recovered and signs of lung clearance of the MWCNT were observed. No pathological changes were observed on the pleura. Neither increase in the number of micronucleated polychromatic erythrocytes nor increase in percent DNA damage were observed at any concentration.

Conclusions: Lung inflammation characteristic of an overload with insoluble particles was observed after a 90-day exposure to 5.0 mg/m(3) of Graphistrength (©) C100. Clear signs of clearance and recovery were observed at 0.25 mg/m(3). No genotoxicity was detected locally in lung and distally in bone marrow, liver and kidney. Therefore, Graphistrength (©) C100 appears of low concern in term of local and systemic genotoxicity and a No-Observed Adverse Effect Concentration (NOAEC) of 0.25 mg/m(3) (0.28 mg/m(3) as actual concentration) was established for the repeated-dose toxicity.

No MeSH data available.


Related in: MedlinePlus

Electron microscopic images of Graphistrength© C100. SEM of the commercial Graphistrength© C100. (a) Magnification: 22 fold. (b) Magnification: 120 fold. (c) Magnification: 10’000 fold
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Fig5: Electron microscopic images of Graphistrength© C100. SEM of the commercial Graphistrength© C100. (a) Magnification: 22 fold. (b) Magnification: 120 fold. (c) Magnification: 10’000 fold

Mentions: Graphistrength© C100, are exclusively produced by Arkema France, Colombes, France. SEM and TEM images (Fig. 5) show that Graphistrength© C100 is made of tightly bound agglomerates constituted with entangled MWCNT. These agglomerates can be spherical, ovoid or irregular shaped and have a granulometry centred on 400 μm, with fragments of pellets of less than 15 μm representing a volume of under 0.23 % [27]. The MWCNT of Graphistrength© C100 are synthesized at high temperature using a fluidized bed with ethylene as a carbon feedstock and iron oxide (Fe2O3, ≤5 %, [1309-37-1]) on alumina (Al2O3, ≤7 %, [1344-28-1]) as catalytic source. Batches nos. 8287 and 110329-018 of Graphistrength© C100 were used for the 5-day and the 90-day exposure studies, respectively.Fig. 5


Lung inflammation and lack of genotoxicity in the comet and micronucleus assays of industrial multiwalled carbon nanotubes Graphistrength(©) C100 after a 90-day nose-only inhalation exposure of rats.

Pothmann D, Simar S, Schuler D, Dony E, Gaering S, Le Net JL, Okazaki Y, Chabagno JM, Bessibes C, Beausoleil J, Nesslany F, Régnier JF - Part Fibre Toxicol (2015)

Electron microscopic images of Graphistrength© C100. SEM of the commercial Graphistrength© C100. (a) Magnification: 22 fold. (b) Magnification: 120 fold. (c) Magnification: 10’000 fold
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4496819&req=5

Fig5: Electron microscopic images of Graphistrength© C100. SEM of the commercial Graphistrength© C100. (a) Magnification: 22 fold. (b) Magnification: 120 fold. (c) Magnification: 10’000 fold
Mentions: Graphistrength© C100, are exclusively produced by Arkema France, Colombes, France. SEM and TEM images (Fig. 5) show that Graphistrength© C100 is made of tightly bound agglomerates constituted with entangled MWCNT. These agglomerates can be spherical, ovoid or irregular shaped and have a granulometry centred on 400 μm, with fragments of pellets of less than 15 μm representing a volume of under 0.23 % [27]. The MWCNT of Graphistrength© C100 are synthesized at high temperature using a fluidized bed with ethylene as a carbon feedstock and iron oxide (Fe2O3, ≤5 %, [1309-37-1]) on alumina (Al2O3, ≤7 %, [1344-28-1]) as catalytic source. Batches nos. 8287 and 110329-018 of Graphistrength© C100 were used for the 5-day and the 90-day exposure studies, respectively.Fig. 5

Bottom Line: Graphistrength (©) C100 multiwalled carbon nanotubes (MWCNT) provide superior electrical and mechanical properties for various applications.The evaluation of the intrinsic hazard properties of Graphistrength(©) C100 is an essential step for safe use.Therefore, Graphistrength (©) C100 appears of low concern in term of local and systemic genotoxicity and a No-Observed Adverse Effect Concentration (NOAEC) of 0.25 mg/m(3) (0.28 mg/m(3) as actual concentration) was established for the repeated-dose toxicity.

View Article: PubMed Central - PubMed

Affiliation: Harlan Laboratories Ltd, Zelgliweg 1, 4452, Itingen, Switzerland. Daniela.pothmann@gmx.de.

ABSTRACT

Background: Graphistrength (©) C100 multiwalled carbon nanotubes (MWCNT) provide superior electrical and mechanical properties for various applications. The evaluation of the intrinsic hazard properties of Graphistrength(©) C100 is an essential step for safe use. A general feature of multiwalled carbon nanotubes after inhalation or intratracheal exposures is the induction of an inflammatory reaction in the lungs sometimes associated with local genotoxic effects.

Methods: After investigating different parameters for the aerosol generation and performing a 5-day inhalation range finding study, male and female Wistar rats were exposed nose-only for 90 days to target concentrations of 0.05, 0.25 and 5.0 mg/m(3) air of Graphistrength (©) C100 and sacrificed 24 h and 90 days after the last exposure. Broncho-alveolar lavage fluid (BALF) was also collected and analyzed for inflammatory parameters. Twenty-four hours post-exposure, chromosomal aberrations in the bone marrow cells were evaluated by the micronucleus test and DNA damages in the lung, kidney and liver cells by both the standard and the human 8-oxoguanine DNA N-glycosylase 1 (hOGG1)-modified comet assay. All studies were performed according to the OECD test guidelines.

Results: An inflammatory lung reaction and the release of inflammatory factors in the BALF were observed in all rats exposed to 5.0 mg/m(3), associated with changes in the differential white blood cells counts. The slight changes in BALF parameters at 0.25 mg/m(3) recovered and signs of lung clearance of the MWCNT were observed. No pathological changes were observed on the pleura. Neither increase in the number of micronucleated polychromatic erythrocytes nor increase in percent DNA damage were observed at any concentration.

Conclusions: Lung inflammation characteristic of an overload with insoluble particles was observed after a 90-day exposure to 5.0 mg/m(3) of Graphistrength (©) C100. Clear signs of clearance and recovery were observed at 0.25 mg/m(3). No genotoxicity was detected locally in lung and distally in bone marrow, liver and kidney. Therefore, Graphistrength (©) C100 appears of low concern in term of local and systemic genotoxicity and a No-Observed Adverse Effect Concentration (NOAEC) of 0.25 mg/m(3) (0.28 mg/m(3) as actual concentration) was established for the repeated-dose toxicity.

No MeSH data available.


Related in: MedlinePlus