The Toxicologist - Society of Toxicology

greatest in SED DES10. Phospholamban expression increased with DES. pSer16-
PLB was reduced in all DES groups but pThr17-PLB had an inverted U response.
After swim, SERCA2a increased in VEH and remained high with DES. CSQ and
PLB were reduced; pSer16-PLB and pThr17-PLB levels increased. Systolic and diastolic
blood pressure was significantly reduced after DES1. Fractional shortening
and EKG did not change. SWIM increased the relative wall thickness only in
VEHs. Conclusion: DES-mediated changes in calcium homeostasis due to altered
cardiac gene expression led to an increased capacity for calcium transport and storage
and the observed differences in cardiac mass and function in adult progeny.
DES negatively affected the ability to accommodate swim. We conclude that gestational
DES alters cardiac structure/function and expression of calcium homeostasis
proteins in adult male progeny.
2189 TESTOSTERONE-MEDIATED PROGRAMMING OF
ADULT FEMALE MOUSE HEART.
W. Noiles, I. Sebag and L. Chalifour. Lady Davis Institute, Montreal, QC, Canada.
Sponsor: K. Mann.
Rationale: Sex hormones are important for cardiac function. Fetal testes secrete
testosterone and cardiomyocytes express androgen receptors leading to the idea that
the fetal heart could respond to androgen programming. We hypothesize that gestational
delivery of androgen will impact cardiac structure/function and calcium
homeostasis expression in adult female progeny. Methods and Results: Pregnant
C57Bl/6n mice (n=4) were injected subcutaneously with peanut oil (VEH) or
testosterone proprionate (TP) during gestation days (GD) 11-14 (20ug, 200ug/kg
body weight (BW)) or GD14-18 (2ug, 20ug, 200ug/kg BW). BW and anogenital
distance (AGD) was measured. Echocardiography, EKG and blood pressure measured
cardiac function. Organ weights were measured at 4M. Immunoblots of heart
homogenates measured expression. BW was not significantly altered. Females
treated GD14-18 with TP200 or GD11-14 with TP20 and TP200 had significantly
longer AGD. At euthanasia female GD14-18 TP200 mice had significantly
larger uteri due to a lack of vaginal opening. Mice after TP GD 14-18 injections
failed to show significant changes in EKG parameters but TP treated GD 11-14
treated females had a significantly shorter QRS than VEH. Blood pressure was unaffected
by treatment. GD 14-18 TP2 treated mice showed significantly reduced
fractional shortening compared to VEH and a larger left ventricular inner-diameter
compared with VEH, TP20 or TP200. All TP treated GD 14-18 females had significantly
lower levels of the sodium-potassium ATPase and calreticulin than VEH.
Significantly lower L-Type calcium channel was only detected in the TP2s.
Conclusion: Gestational testosterone proprionate in the experimental design was
adequate to masculinize female reproductive organs. Gestational TP significantly
altered cardiac function and protein expression in GD11-14 and GD14-18 adult
female progeny. These effects are mediated in a non-monotonic dose response, with
the lower concentration of TP having a greater effect on cardiac function and the
higher concentration a greater effect on expression. Gestational TP programs female
fetal hearts.
2190 EARLY LIFE PARTICLE AND OZONE INHALATION
SENSITIZES THE LUNG AND BRAIN TO LATER LIFE
CHALLENGES.
C. J. Johnston 1, 2 , J. Allen 2 , R. Gelein 2 , J. N. Finkelstein 1, 2 , G. Oberdörster 2
and D. A. Cory-Slechta 2 . 1 Pediatrics, University of Rochester Medical Center,
Rochester, NY and 2 Environmental Medicine, University of Rochester Medical Center,
Rochester, NY.
Epidemiological studies conducted in the United States and elsewhere suggest that
childhood pulmonary diseases are increasing at an alarming rate. The EPA is required
to set National Ambient Air Quality Standards (NAAQS) for particulate
matter and ozone to protect public health with an adequate safety margin.
However, these studies are done in the adult or aged animal models. We hypothesize
that pulmonary exposure to ambient traffic related particles or ozone during
postnatal lung development causes structural alterations and increased sensitivity to
secondary challenges as adults. 4 day old C57Bl/6J mice were exposed to ambient
“Real World” ultrafine and fine particles or ozone to examine how early life exposures
effect re-exposure as adults. Groups of 4 day old mice were exposed for 4
hours a day for 4 consecutive days for 2 weeks and allowed to recover until 8 weeks
of age. Mice were either sacrificed or re-exposed for 4 days and examined at the end
of exposure. Endpoints examined were respiratory and CNS inflammatory markers.
In addition, translocation of inhaled nanoparticles to the CNS and other secondary
organs was determined. Microarray analysis demonstrated that re-exposure
as adults induced mRNAs encoding cell cycle, antioxidant, proinflammatory cytokines
and chemokines. Pulmonary lavage data demonstrated an increased neu-
470 SOT 2011 ANNUAL MEETING
trophilic influx in the lungs of challenged mice as compared to those only exposed
as adults. Inhalation of gold showed greater accumulation in the kidney and spleen
of re-exposed adults. Pollutant exposure during postnatal lung development
demonstrated enhanced responses after re-challenge as compared to age matched
mice which were only exposed as adults. Our results demonstrate increased sensitivity
indicating that the lung is damaged or primed by earlier events, so exposure to
a non-toxic dose of an environmental pollutant will trigger adverse responses.
Funded By:ES-01247 and EPA PM Center R-827354.
2191 INTERSPECIES APPROACH TO THE ASSESSMENT OF
HUMAN SUSCEPTIBILITY TO PHTHALATE-INDUCED
ENDOCRINE DISRUPTION.
N. Heger 1 , S. J. Hall 1 , M. A. Sandrof 1 , E. V. McDonnell 1 , J. B. Hensley 4 , K. J.
Johnson 3 , E. Houseman 2 , K. W. Gaido 4 and K. Boekelheide 1 . 1 Pathology and
Lab. Medicine, Brown University, Providence, RI, 2 Community Health, Brown
University, Providence, RI, 3 duPont Hospital for Children, Wilmington, DE and
4 The Hamner Institutes for Health Sciences, Research Triangle Park, NC.
A testicular dysgenesis syndrome has been proposed, suggesting that alterations to
the in utero and perinatal hormonal environment may explain temporal increases
in male reproductive tract abnormalities. In utero exposure of male rats to the plasticizer
di-(n-butyl) phthalate (DBP) reveals suppression of fetal testicular steroidogenesis,
while mice remain relatively unaffected. To examine this species-specific
sensitivity, a rodent host bioassay consisting of rodent and human fetal testicular
grafts was developed. To validate the bioassay, fetal mouse (gd15) or rat (gd16)
testes were xenografted into the renal subcapsular space of nude rat or mouse hosts,
exposed to 250mg/kg/d DBP for 1, 2, or 3 days, and harvested 6 hours after the
final dose. In DBP-exposed hosts, an increase in multinucleated germ cell (MNG)
content was observed in both rat and mouse xenografts, with only rat xenografts exhibiting
suppressed steroidogenic gene expression, consistent with the intact response.
DBP treatment did not affect germ-cell content, and host species did not
influence histopathology or gene expression endpoints. To explore the human response,
a similar exposure paradigm was used, xenografting fetal testes (gestational
weeks 10-23, n=17) into nude rat hosts. A significant increase in multinucleated
germ cell content was observed following DBP exposure. RT-PCR analysis of
steroidogenic genes revealed no DBP-induced alterations on any day. Taken together,
these findings suggest that the human fetal testis responds more like the
mouse than the rat following developmental phthalate exposure, and that the resulting
effects on seminiferous cords and steroidogenic gene expression are mechanistically
distinct, species-specific and intrinsic to the testis.
2192 LACK OF TRANSGENERATIONAL EFFECT FOR
VAGINAL PATENCY AND UTERINE WEIGHT IN CD-1
MICE EXPOSED TO DIETHYLSTILBESTROL OR
17BETA-ESTRADIOL.
E. Carney, R. J. Rasoulpour, M. J. LeBaron, J. Murray, R. Sura, J. Passage, R.
Ellis-Hutchings and B. Gollapudi. The Dow Chemical Company, Midland, MI.
Epigenetic modifications, defined as heritable changes in gene expression via mechanisms
other than changes in DNA sequence, can be passed through the germ line
to influence transgenerational inheritance. Recent studies suggested that chemical
exposure of pregnant mice can cause epigenetic changes in the (F1) conceptuses,
which can be inherited by subsequent generations. To further explore this phenomenon,
groups of 25 pregnant F0 CD-1 mice were administered ~10 μg/kg/day diethylstilbestrol
(DES) or ~30 μg/kg/day 17beta-estradiol (E2) via the diet or subcutaneous
injection (SC) from gestation day 9 – lactation day (LD) 20. F1
offspring were mated for two additional generations, with F1-F3 offspring evaluated
for uterotrophic effects on postnatal day (PND) 21 and vaginal patency.
Exposed F0 dams in all groups had a 33-42% increase in LD 21 relative uterine
weight. The F1 generation had a 3-4-fold increase in relative uterine weight for
both DES and E2 diet groups; however, no effect was observed when DES and E2
were administered SC. All F1 groups had a treatment-related acceleration of vaginal
patency. In addition, the F1 females from the DES SC group were subsequently
found to be infertile, precluding further evaluation of this group. Surprisingly, there
were no grossly observable uterine tumors at the 12-month interim necropsy conducted
on a subset of the F1 generation; however histopathology and 18-month
terminal tumor incidence data are pending. In the F2 generation, there was a marginal
increase in mean PND 21 uterine weights for the dietary groups, but no indication
of uterotrophic effects in the E2 SC group. Unlike the first generation, there
was no effect on vaginal patency in the F2 litters. In the F3 generation, there was no