The Toxicologist - Society of Toxicology

croscopic analysis revealed that only nSP70 reached langerhans cells and draining
lymph node. Because langerhans cells are sentinels of innate and acquired immunity,
nSP-application may have potential immune-modulating effect in vivo. Thus,
we next investigated whether the induction of antigen-specific immune responses
after intra-dermal injection of the mixture of nSP and model antigen, chicken egg
ovalbumin (OVA) by IFN-γ ELISPOT assay. Results indicated that nSPs with a diameter
below 100 nm more strongly induce IFN-γ producing cytotoxic T lymphocytes
specific for OVA than conventional micro-sized SPs. Our results indicate that
the size of NMs as well as the target cell type is critical determinants for the design
of safer nSPs.
2084 DISTRIBUTION IN THE TESTIS AND REPRODUCTIVE
EFFECTS OF NANOSILICA.
Y. Morishita 1, 2 , Y. Yoshioka 1, 2, 3 , K. Yamashita 1, 2 , K. Higashisaka 1, 2 , M.
Fujimura 1, 2 , H. Pan 1, 2 , T. Ogura 1, 2 , K. Nagano 2 , Y. Abe 2 , H. Kamada 2, 3 , S.
Tsunoda 2, 3, 4 , H. Nabeshi 1 , N. Itoh 1 , T. Yoshikawa 1, 2 and Y. Tsutsumi 1, 2, 3 .
1 Department of Toxicology and Safety Science, Graduate School of Pharmaceutical
Sciences, Osaka University, Suita, Osaka, Japan, 2 Laboratory of Biopharmaceutical
Research, National Institute of Biomedical Innovation, Ibaraki, Osaka, Japan, 3 The
Center for Advanced Medical Engineering and Informatics, Osaka University, Suita,
Osaka, Japan and 4 Department of Biomedical Innovation, Graduate School of
Pharmaceutical Sciences, Osaka University, Suita, Osaka, Japan.
Nanomaterials (NMs) are already being applied in universal fields such as electronics,
cosmetics, foods, and drugs. However, the increasing use of NMs has raised
public concern about their safety. Therefore, it is necessary to investigate the safety
of NMs based on biodistribution and biological responses. Especially the reproductive
effect of NMs is important issue for preventing the toxicity to offspring. In this
study, we examined the effects of nanosilica particles (nSP), one of the most popular
NMs, to testis by analyzing the biodistribution to the testis and measuring testicular
hormone. We already found that nSP could enter blood circulation by oral,
nasal and dermal administrations. Therefore, to assess the biodistribution after entering
blood circulation, we analyzed the biodistribution of nSP to the testis after
intravenous injection by transmission electron microscopy. nSP with a diameter of
70 nm were detected in sertori cells and spermatocyte, although we did not observe
any particles in the testis of larger silica particles-treated mice. Next, we measured
the level of testosterone in blood after treatment with nSP via intravenous, oral or
nasal administrations. The level of testosterone in nSP-treated mice was different
from control mice. These data suggest that nSP could penetrate blood-testis barrier
and might induce testicular disorders.
2085 BIODISTRIBUTION AND REPRODUCTIVE TOXICITY
OF NANOSILICA FOR ENSURING THE SAFETY OF
NANOMATERIALS.
K. Yamashita 1, 2 , Y. Yoshioka 1, 2, 3 , K. Higashisaka 1, 2 , M. Fujimura 1, 2 , Y.
Morishita 1, 2 , H. Pan 1, 2 , T. Ogura 1, 2 , H. Nabeshi 1 , K. Nagano 2 , Y. Abe 2 , H.
Kamada 2, 3 , S. Tsunoda 2, 3, 4 , N. Itoh 1, 2 , T. Yoshikawa 1, 2 and Y. Tsutsumi 1, 2, 3 .
1 Department of Toxicology and Safety Science, Graduate School of Pharmaceutical
Sciences, Osaka University, Osaka, Japan, 2 Laboratory of Biopharmaceutical
Research, National Institute of Biomedical Innovation, Osaka, Japan, 3 The Center for
Advanced Medical Engineering and Informatics, Osaka University, Osaka, Japan and
4 Department of Biomedical Innovation, Graduate School of Pharmaceutical Sciences,
Osaka University, Osaka, Japan.
Recently, many nanomaterials (NMs) with innovative functions have been developed
and already used in several fields. However, knowledge concerning the potential
safety of NMs is still fragmentary. Especially, few studies have examined the effect
of NMs on maintenance of pregnancy. In this study, we examined the
biodistribution and reproductive toxicity of nanosilica particles with different size
and surface modification. Pregnant BALB/c mice were treated with silica particles
with a diameter of 70, 300 or 1000 nm (nSP70, nSP300 or mSP1000, respectively)
via intravenous injection. At first, we examine the biodistribution of silica particles
in placenta and fetuses. nSP70 was detected in not only placenta but also fetal liver
and fetal brain, although nSP300 and mSP1000 were not detected in these tissues
at all. Next, we examined the influence of silica particles on fetuses. nSP70-treated
pregnant mice showed the increase of fetal resorption rates and decrease of fetal
weights compared to control mice, suggesting that nSP70 induced the miscarriage
and fetal growth restriction. In contrast, nSP300 and mSP1000 did not induce
these pregnant complications. Furthermore, we showed that nSP70 with functional
COOH or NH2 surface modification group did not induce miscarriage and fetal
growth restriction. These results suggest that nSP70 induce the miscarriage and
fetal growth restriction, and appropriate surface modification suppresses these pregnancy
complications. We believe that our findings provide useful information for
ensuring the safety of NMs.
2086 INACTIVATION OF ENDOCANNABINOID
METABOLISM IN HUMAN THP1 MACROPHAGES
FOLLOWING EXPOSURE TO ACTIVATED
ORGANOPHOSPHOTHIONATES.
M. K. Ross 1 , A. Borazjani 1 and P. M. Potter 2 . 1 Mississippi State University,
Mississippi State, MS and 2 St. Jude Children’s Hospital, Memphis, TN.
Atherosclerosis results from chronic inflammation and dysregulated lipid metabolism.
We hypothesize that the endocannabinoid tone of vessel wall macrophages
may be perturbed by chronic exposure to activated organophosphothionate insecticides,
thus an activated endocannabinoid system may modulate cholesterol metabolism
in macrophages. When human THP1 macrophages were cholesterol loaded
and subsequently treated with chlorpyrifos oxon (CPO) or paraoxon (PO) (0, 1
and 10μM) for 24h, increasing amounts of the endocannabinoid 2-arachidonoylglycerol
(2AG) was secreted. For the 1μM and 10μM CPO treatment groups,
amounts of 2AG were 2.5-fold and 8.1-fold higher than the control group, respectively.
In contrast, 1μM and 10μM PO resulted in 3.1-fold and 3.5-fold increases
in 2AG levels, respectively. This result suggested that THP1 foam cells are capable
of 2AG biosynthesis and secretion. It further showed that oxon-mediated inhibition
of catabolic enzymes in foam cells contributes to the buildup of 2AG in culture
medium in a dose-dependent manner, which is due to inactivation of CES1 and
other hydrolytic enzymes. Furthermore, addition of exogenous 2AG to LPSprimed
THP1 macrophages, which mimics stimulation of inflamed cells by autacoids
such as endocannabinoids, caused significant amounts of prostaglandins
(PGF2α and PGE2) to be secreted compared to LPS-primed cells that did not receive
2AG (10-40-fold higher). However, enhanced production of PGs was
markedly attenuated 2-4-fold by addition of a CES1 small molecule inhibitor. This
result indicated that PG formation by THP1 macrophages is mainly regulated by
2AG hydrolysis since the pool of arachidonic acid produced following 2AG hydrolysis
is directed toward PG biosynthesis. The possibility that endocannabinoid metabolism
and subsequent COX-mediated oxygenation of arachidonic acid is perturbed
following exposure of macrophages to OP insecticides suggests a novel role
for these xenobiotics in vascular wall dysfunction. [Supported by NIH
R15ES015348]
2087 ETHYLENE BISDITHOCARBAMATE PESTICIDES
MANEB AND MANCOZEB CAUSE TOXICITY IN
NORMAL AND TRANSFORMED COLON CELLS.
H. M. Lisa and D. Hardej. Department of Pharmaceutical Sciences, St. John’s
University, Queens, NY.
Ethylene bisdithiocarbamate pesticides maneb (MB) and mancozeb (MZ) are
broad range contact fungicides used for eradication of fungal infection on a wide
variety of crops. Although reported to possess low acute toxicity to humans, scientific
evidence suggests that toxicity does occur. The purpose of this study was to investigate
toxicity of MB and MZ in human CCD-Co18, Caco2, and HT29 colon
cells. Previous testing in our laboratory has established the acute toxicity of these
agents in HT29 and Caco2 cell lines. Significant decreases in cell viability were observed
in HT29 cells from 200-400μM and in Caco2 cells from 100-400μM for
both compounds. Preliminary data with normal colon cells, CCD-Co18, shows a
similar pattern of acute toxicity, with significant decreases in cell viability ranging
from 100-400μM for both agents. To investigate chronic toxicity, cells were exposed
to concentrations of both agents ranging from 12.5-200μM for HT29 and
0.625-10μM for Caco2 cells for 10 days and viability assessed by the MTT assay.
HT29 cells showed significant decreases in cell viability at all concentrations on
days 2 through 10 for both agents. Caco2 cells exposed to MB showed significant
decreases in cell viability in concentrations 2.5-10μM on days 4 through 8, from
1.25-10μM on day 6, and 5-10μM on day 10. Upon MZ exposure, Caco2 cells
showed significant decreases in cell viability on days 4 and 6 from 1.25-10μM, day
8 from 0.625-10μM, and day 10 from 2.5-10μM. To evaluate if cellular injury resulted
in lipid peroxidation, thiobarbituric acid reactive substances (TBARS) assay
was performed on concentrations 100-200μM for both agents in HT29 cells and
20-60μM for both agents in Caco2 cells. Lipid peroxidation was not observed in either
cell line with either compound at the concentrations tested. We conclude that
the acute toxicity seen in transformed colon cells is comparable to normal cells at
the concentrations tested and that chronic toxicity in HT29 and Caco2 cells occurs
at significantly lower doses.
SOT 2011 ANNUAL MEETING 447