The Toxicologist - Society of Toxicology

that the iron overload observed is likely due to a genetic component. Although the
incidence of iron overload in the Hsd:HHCL rat population was very low, this
could be due to a rare allele, possibly with incomplete penetrance. These findings
are unique in that there are no known models of rat hemochromatosis other than
ones that are diet-induced and all models of HHC are mouse knock-out models. As
mice are not always suitable models for human disease research, the Hsd:HHCL rat
could be a better model of human hemochromatosis. This model is potentially useful
for development of treatments for HHC and for understanding the molecular
mechanisms for regulation of iron metabolism.
512 PAIN ASSESSMENT IN MONOSODIUM IODOACETATE
(MIA)-INDUCED OSTEOARTHRITIS (OA) MODEL.
R. Samadfam, L. Chouinard and S. Y. Smith. Toxicology, Charles River Preclinical
Services, Montreal, QC, Canada. Sponsor: M. Vézina.
Major findings in basic science of pain have failed to bring new drugs into clinical
practice, partly due to the fact that the preclinical models used for pain assessments
do not adequately represent the clinical condition. A potentially useful approach to
evaluate antinociceptives is using animal models with diseases similar to humans
such as OA. The objectives of this study were to determine the optimal dose of
MIA to induce joint discomfort in rats and develop/validate relevant pain endpoints.
Measurement of dynamic weight bearing (DWB) quantifies a spontaneously
emitted behavior, providing more clinically relevant results compared to reflexive
measurements (Von Frey filament (VFF) or pinch). Adult rats were assigned
to three groups, each receiving an intra-articular injection of saline or MIA at 1 or
3 mg/dose in the right knee. Pain was evaluated at Day 14 using: body position,
gait, toe pinch, modified grip strength test VFF and DWB. Animals with more severe
symptoms of OA were treated with Naproxen and pain was evaluated once predose,
4 and 6 hours post dose. Animals treated with 1 mg/dose generally had less severe
OA symptoms with normal body position and gait and only trends of an
altered weight bearing of the right rear paw compared to controls. Animals treated
with 3 mg/dose had more severe OA had normal gait and clearly showed signs of
joint discomfort (right rear paw) as measured by DWB. Modified grip strength test
indicated the right rear paw was weaker than the untreated left rear paw. The VFF
test was the most sensitive endpoint for this model with significant differences between
the right and left rear paws. Naproxen reduced pain in the majority of the 3
mg/dose animals as evidenced by balanced weight distribution and comparable use
of both rear paws. These results indicate that reflexive pain measures were successfully
measured at 1 mg/dose. However, the 3 mg/dose produced consistent quantitative
changes and was considered the optimal dose of MIA to assess pain in a more
clinically relevant condition (spontaneously emitted behavior) using DWB.
513 PROTEOMIC ANALYSIS OF MAINSTREAM CIGARETTE
SMOKE-EXPOSED FISHER RAT NOSES IN A SHORT-
TERM STUDY.
C. A. Carter and M. Misra. Life Sciences, Lorillard Tobacco Company, Greensboro, NC.
A short-term 5 day nose-only smoke exposure study was conducted in Fisher 344
rats to identify smoke-induced nose protein changes. Groups of 10 male and female
5 wk old rats were assigned to 1 of 4 exposure groups. Animals received filtered air,
or 75, 200 or 400 total particulate matter (TPM) mg/m 3 of diluted 3R4F
Kentucky reference cigarette mainstream smoke. Exposures were conducted for 3
hrs/day, for 5 consecutive days. Half of the harvested nose tissue was decalcified and
processed for pathology, while the soft tissues were removed from the other half and
processed for proteomic analysis. We hypothesized that inflammation pathways are
activated in nasal tissues. Changes in smoke-treated animals included loss of ciliated
epithelium, hyperplasia and metaplasia of the respiratory epithelial septum, and increases
in serous exudate and inflammation. Nose lysates from control vs. treated
animals were screened for 800 proteins using antibody-based microarray technology
and the 18 most changed proteins were evaluated by Western blot. Proteins
that were expressed at high levels in the nose and are markedly increased or decreased
by smoke treatment depended on dose and gender and included: heat shock
protein 90 (Hsp90), serine/threonine protein kinase 33 (STK33), protein kinase Cdelta
and zeta, p53 apoptosis effector related to PMP-22 (PERP), and interleukin-
1 receptor-associated kinase-like 2 (IRAK2). Thus, smoke affected protein pathways
that are involved in stress, inflammation, proliferation, apoptosis, and
transformation. Inflammatory mediators were the common change observed both
with proteomics and pathology. Proteomics is a powerful method for identifying
key pathways affected by smoke exposure. Changes in identified proteins affected
by smoke exposure may induce functional changes in the nose and could serve as
early indicators of nasal damage and associated disease.
110 SOT 2011 ANNUAL MEETING
514 FIRST IN MONKEY (FIM) PERFORMED TRACKING OF
MAGNETIC CAPSULE INSIDE THE
GASTROINTESTINAL TRACT WITH 3D-MAGMA.
H. Richert 2 , S. H. Korte 1 and S. Abert 2 . 1 Covance Laboratories GmbH, Muenster,
Germany and 2 Matesy GmbH, Jena, Germany. Sponsor: G. Weinbauer.
In order to reach a maximum benefit in oral drug absorption new substances shall
be tested for their permeability in different regions of the human GI-tract.
Furthermore, for toxicological investigations of oral drug forms it is often necessary
to release a new candidate within a specific region inside the gastrointestinal tract.
Remote controlled drug release into the gastrointestinal tract can be done with the
innovative system 3D-MAGMA/MAARS, which acts magnetically for capsule localization
and for drug release.
In this first study one fasted, non sedated male Cynomolgus monkey (macaca fascicularis)
was used to test and visualize the gastrointestinal transit of a magnetic capsule.
With the magnetic monitoring system 3D-MAGMA the capsule was monitored
over 100 min every 20 min for 2 to 6 min. The system measured the
3D-position of a magnetic marked capsule and estimated in real time the travelled
path and local motility patterns of the GI tract. Following results could be achieved:
Within the first 90 minutes after capsule application a dominant frequency of approx.
2.7 to 3.3 min-1 could be determined and the three-dimensional capsule position
was detected in the region of the stomach. According to the literature, the
slow waves in the stomach have a frequency of about 3 min-1 in Cynomolgus monkeys
(similar to humans), so the capsule was surely inside the stomach. 90 minutes
after start of the investigation the dominant frequencies and the capsule position
changed. The known intestinal slow waves with a frequency of about 12 min-1
could be found, so that we could assume that the capsule had successfully traveled
into the small intestine. The animals breathing frequency of about 50 min-1 was always
visible.
CONCLUSION: It seems to be feasible to identify the capsule position during the
intestinal transit by evaluating the occurring motility pattern combined with the 3d
position of magnetic capsule. Complete visualizations of intestinal passages in nonsedated
monkeys are difficult because of short measurement intervals.
515 TOXIC EFFECTS OF ETHYL TERTIARY BUTYL ETHER
EXPOSURE IN CYP2E1 KNOCKOUT MICE.
R. Wang 1 , Y. Yanagiba 1 , K. Ohtani 1 , M. Suda 1 , Z. Weng 1 and T. Nakajima 2 .
1 Japan National Institute of Occupational Safety and Health, Kawasaki, Japan and
2 Nagoya University School of Medicine, Nagoya, Japan. Sponsor: N. Mei.
Ethyl Tertiary Butyl Ether (ETBE) is used as a fuel oxygenate in gasoline. Previous
studies with animals indicated that the toxicity of this chemical is low. ETBE is metabolized
in body by CYP2E1 as well as CYP2A6 to two primary intermetabolites,
acetaldehyde and t-butyl alcohol, which are believed to be toxic. Therefore, the
transformation of ETBE in body is critical for its toxicity. In this study, we used
CYP2E1 knockout mice to investigate if there is any change in the susceptibility to
the toxic effects of ETBE. METHODS: Wild type SV129 mice and its CYP2E1
knockout mice were exposed to ETBE at 0, 500, 1750 and 5000 ppm ETBE, 6
hr/day and 5 days/week, for 6 weeks. Blood, liver and epididymides were sampled
20 hr after the last exposure. RESULTS: Increase in the ratio of liver/body weight
was only observed in 5000 ppm exposure of both genotypes of mice; as for the effects
on hemotology, there was a tendency of dose-dependent increase in the erythrocyte
counts and hemoglobin concentrations in the groups of exposure of either
wild type or knockout mice, but statistical differences were only found between the
middle and high doses groups and the controls of wild type mice. ETBE exposure
also affected the motility of sperm, as showed by the significantly low percentages
of motile and progressive sperm with the two high doses of ETBE. The reproductive
effect was observed in both types of mice at approximately similar extent. These
results indicated that while CYP2E1 may play a role in the metabolism of ETBE,
lack of the enzyme has little influence on the toxic effects of the chemical. We thank
Ms. S. Watanabe for her assistance in the manipulation of animals.
516 THE INDIVIDUAL AND INTERACTIVE EFFECTS OF
LIPOPOLYSACCHARIDE AND DEOXYNIVALENOL ON
FREE FATTY ACIDS IN THE LIVER AND BRAIN OF RATS.
I. Ross 1 , T. Boyle 1 , W. D. Johnson 1 , L. H. Garthoff 1 , S. M. Ahn 1 , M. W.
O’Donnell 2 and C. S. Kim 1 . 1 U.S. FDA, Laurel, MD and 2 Biostatistics Branch,
Laurel, MD. Sponsor: H. Luu.
Post-translocation modification by the palmitate is crucial for the correct targeting
and function of many proteins in cells. Mutation of palmitation site makes palmitation
resistant and increases neuronal toxicity in the brain. Palmitoylation of immune
effectors is known to be crucial for host resistance to infections. This research