The Toxicologist - Society of Toxicology

enced by pre-exposure to cigarette smoke (CS), we exposed female A/J mice to sidestream
cigarette smoke for 6hrs/d, 5d/wk for 4 wks and then challenged them with
a single dose of 40μg multiwall carbon nanotubes (CNT) in 50 μl of phosphate
buffered saline (PBS) by pharyngeal aspiration. Control animals exposed to ambient
air received 50 μl PBS. Pulmonary response was compared in a total of four
groups: 1) Air/PBS-control, 2) CS/PBS, 3) Air/CNT, and 4) CS/CNT.
Bronchoalveolar lavage fluid (BALF) samples were collected at 24 and 72 hrs post-
CNT treatment. BALF was analyzed for various markers of cytotoxicity and inflammation
using standard ELISA and immunoblot assays. The results showed a
pronounced cellular response and increase in various cytotoxicity/inflammatory
markers (total BALF protein, LDH, cytokines and mucin) in the lungs of CNT-exposed
mice. Pre-exposure to CS for 4wks, by itself, produced minimal effects and
generally did not affect cytotoxic responses such as BALF protein and LDH.
However, BALF cytokine response to CNT was suppressed in CS-pre-exposed animals
in comparison to corresponding air-exposed CNT controls. While cytokine
levels returned to baseline by 72hrs,significantly higher levels of BALF mucin persisted
in air and CS-exposed mice at 24 and 72 hrs post-CNT administration.
These results suggest the development of “cross tolerance” similar to that observed
in our earlier studies of ozone-CNT interaction and demonstrate that prior exposures
can modulate toxic response (supported in part by funds from OVPR,WSU).
1191 INHALATION OF SINGLE-WALL CARBON
NANOTUBES INCREASES APOPTOSIS AND
ENDOTHELIN-1 LEVELS IN HAMSTER LUNGS.
K. H. Bijlani, H. R. Sukhija, J. O. Cantor and J. M. Cerreta. PHS, St. Johns
University, Queens, NY. Sponsor: L. Trombetta.
Single-wall carbon nanotubes (SWCNT) consist of a graphene sheet rolled into a
cylinder with diameters of few nanometers (nm) and length that may range up to a
micrometer. SWCNT have potential applications as superconductor material and
in biosensors, with human exposure occurring in the workplace. The current study
was undertaken to evaluate the effects of inhalation exposure of aerosolized
SWCNT on hamster lungs. Golden Syrian Hamsters were divided in to 2 groups: a
control group that was exposed to an aerosol of autoclaved distilled water, and a
treated group that was exposed to aerosolized SWCNT at doses of 1mg/m3,
2mg/m3 and 4mg/m3 for 2hrs/day for 4 consecutive days. Additional groups were
used to investigate longer inhalation periods (8 days and 14 days) with exposures of
4hrs/day to 2mg/m3 SWCNT. One day following completion of exposures, hamsters
were euthanized and the lungs were either lavaged or removed for histological
examination. Bronchoalveolar lavage fluid (BALF) was analyzed for total cell count,
and lung tissue sections were stained and examined microscopically. Apoptosis levels
in lung tissue sections were determined by TUNEL Assay and endothelin-1 (ET-
1) levels were also measured. Compared to control groups, hamsters exposed to inhalation
of 1, 2 and 4mg/m3 SWCNT demonstrated an increase in total cell count
of 207%, 273% and 279% respectively. Animals treated with 2 and 4mg/m3 also
had elevated lung ET-1 levels (179% and 213%) respectively. Hamsters treated for
8 or 14 days had BALF cell counts that were increased to 268 % and 410%, respectively,
when compared to controls. Lung ET-1 levels were also increased in the
lungs of hamsters treated for 8 days (207%) and 14 days (237%) in comparison to
controls. Histological examination revealed an increased number of TUNEL positive
cells, alveolar septal thickening and the presence of small granulomatous-like
lesions with higher concentrations of SWCNT. Results from this study suggest that
inhalation of SWCNT induces pulmonary injury in hamsters.
1192 INHALED SINGLE WALL CARBON NANOTUBES
INCREASE LEVELS OF 5–LIPOXYGENASE AND LTB4 IN
HAMSTER LUNGS.
H. R. Sukhija, K. H. Bijlani, J. O. Cantor and J. M. Cerreta. PHS, St. Johns
University, Queens, NY. Sponsor: L. Trombetta.
Single-walled carbon nanotubes (SWCNT) are elongated, cylindrical particles,
with a diameter of 1-2nm, that have applications in electronics and biotechnology
industries. As such materials become more common in the work place, assessment
of their potential hazard becomes important. The current investigation was initiated
to study the possible risk posed by inhaled SWCNT to the lung. Separate
groups of Golden Syrian Hamsters (6-7 weeks old) were exposed to 1mg/m3,
2mg/m3, and 4mg/m3 of SWCNT for 2hrs/day for 4 days. Further studies exposed
animals for 4hrs/day for 8 days and for 14 days with 2mg/m3 SWCNT. All
SWCNT-treated groups were compared to their respective vehicle-treated controls
at 24 hrs following the exposure period. Hamsters were euthanized and their lungs
collected for paraffin-embedding or for lavage. Bronchoalveolar lavage fluids
(BALF) were assessed for total cell numbers, 5–lipoxygenase (LOX), and
leukotriene B4 (LTB4). Lung tissue sections were evaluated for LOX activity by immunohistochemistry.
Hamsters exposed to 1mg/m3, 2mg/m3, and 4mg/m3 of
SWCNT had increased: total BALF cell counts of 2, 2.7 and 2.7 fold, respectively,
and increased LTB4 levels of 2.9, 5.4 and 3 fold compared to the controls. Animals
exposed for 8 days had increased total cell counts (2.6x) and LTB4 levels (11.3x) as
compared to the controls. Fourteen-day exposed animals had an increased total cell
count (4x) and LTB4 levels (3.7x) as compared to the controls. LOX levels increased
in the alveolar septa and in alveolar macrophages as compared to the controls.
Differential cell counts demonstrated foamy macrophages and the presence of
lymphocytes in the treatment groups that were absent from control groups. Such
data indicate that inhaled SWCNT induces pulmonary inflammation in hamsters
with activation of LOX and increased levels of LTB4.
1193 AMPHIPHILIC POLYMER-COATED CdSe /ZnS
QUANTUM DOTS INDUCE LUNG INFLAMMATION IN
MICE WHICH IS MODULATED BY GLUTATHIONE
STATUS.
D. Botta, C. C. White, C. S. Weldy, L. A. McConnachie, J. Wilkerson, S. E.
Gill, X. Hu, W. C. Parks, X. Gao and T. J. Kavanagh. University of Washington,
Seattle, WA.
Quantum dots (QDs) are unique semi-conductor fluorescent nanoparticles with
potential uses in a variety of biomedical applications. However, concerns have been
expressed regarding their potential toxicity, specifically their capacity to induce oxidative
stress. In this study we synthesized CdSe/ZnS core/shell QDs with a tri-noctylphosphine
oxide, poly(maleic anhydride-alt-1-tetradecene) (TOPO-PMAT)
coating and assessed their effects on the respiratory tract of mice. Previous in vitro
data in macrophages had shown these QDs cause mild oxidative stress and secretion
of pro-inflammatory cytokines, and that this was glutathione (GSH)-dependent.
We therefore investigated their effects in vivo in mice genetically engineered to have
deficiencies in GSH (GCLM null mice). When exposed via nasal instillation to a 6
μg/kg Cd equivalent dose of QDs at 8 hours, neutrophil counts in broncho-alveolar
lavage fluid (BALF) increased in both wild-type (WT) as well as GCLM heterozygous
(HT) mice, whereas GCLM null (KO) mice exhibited no increase in
neutrophils. HT mice had a significantly higher level of neutrophils than WT mice.
The NOAEL for HT mice was 0.25 μg/kg Cd equivalents. TOPO-PMAT gold
nanoparticles had no effect on neutrophil influx in either WT or HT mice. Lung
cadmium (Cd) levels peaked at 1 hr in HT mice, but were similar in WT mice at
0.5hr, 1hr and 3hr. Cd levels in KO mice peaked at 0.5 hr. Levels of the pro-inflammatory
cytokines KC and TNFα in BALF increased in the WT and HT mice,
but not in KO mice. There was no change in matrix mettaloproteinase (MMP) activity
in the lungs for any genotype. Neither WT nor HT mice had increased levels
of myeloperoxidase (MPO – a marker of neutrophil influx). Interestingly, there was
a decrease in MPO in the KO mice (irrespective of treatment) relative to untreated
WT mice. We conclude that TOPO-PMAT QDs are pro-inflammatory in vivo in
mice in a GSH-dependent manner. Supported by NIH Grants R01ES016189,
P30ES07033 and T32ES07032.
1194 BIO-DISTRIBUTION OF FULLERENE INTRAVENOUS
ADMINISTRATED IN RAT.
T. Nishimura 1 , R. Kubota 1 , M. Tahara 1 , K. Shimizu 1 , T. Obama 1 , N.
Sugimoto 1 and A. Hirose 2 . 1 Division of Environmental Chemistry, National Institute
of Health Sciences, Tokyo, Japan and 2 Division of Risk Assessment, Biological Safety
Research Center, National Institute of Health Sciences, Tokyo, Japan.
Engineered nanomaterials are applied to pharmaceuticals, foods, cosmetics, and so
on. Among these engineered nanoparticles, it have been increasing the concern
about the exposure risk of fullerenes and their derivatives increases in the occupational
and/or living environment through the oral, dermal and inhalation route by
the rapid commercialization. However, the effect on the human health and the biological
behavior has not studied sufficiently. In this study, we have examined the
distribution of fullerene after injection into the rat tail vein to mimic the digestive
absorption. The fullerene was extracted with toluene from tissues and then measured
by liquid chromatography with tandem mass spectrometry. The fullerene was
detected in liver, kidney, spleen and lung in all injected rats on both the first day
and the fourth day after injection. However, the fullerene was not detected in blood
and brain. The highest concentration was detected in the lung on the first day after
the injection. The average concentration in lung was almost similar to that in liver
and spleen, but much lower in kidney. The concentrations were decreased with the
time dependency in all tissues except spleen on the fourth, fourteenth and twentyeighth
days in comparison with on the first day. The concentration in kidney, however,
had rapidly decreased on fourth day. In the case of pregnancy rats, the
fullerene was also distributed in lung, liver, spleen and kidney. However, the
fullerene was also very low in kidney and could not be detected in placenta and
fetus. These results indicate that the fullerene absorbed in the body via any route of
exposure may distribute to lung, liver, spleen and kidney as the primary exposure
SOT 2011 ANNUAL MEETING 255