OR38-3 Early Exposure to Triclocarban During Lactation Alters Survival Rate in the Female Rat Neonate

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: OR38-Physiological Impacts of Endocrine Disrupting Chemicals
Monday, June 17, 2013: 11:15 AM-12:45 PM
Presentation Start Time: 11:45 AM
Room 256 (Moscone Center)
Rebekah C Kennedy*1, Laura Healy2, Kellie Fecteau1, Ling Zhao1, Pan Hu1, Nancy A Gee3, Bill L Lasley4, Kurt Benirschke5 and Jiangang Chen1
1University of Tennessee, Knoxville, TN, 2HistoTox Labs, Inc., Boulder, CO, 3University of California, Davis, CA, 4Univ of California, Davis, CA, 5University of California, San Diego, CA
Triclocarban (TCC), a bactericide in personal care products, has been shown to impact sex and thyroid hormone function in vitro and influence adult sex organ accretion in vivo.   This study investigates the critical period of TCC exposure in utero and during lactation through a cross-fostering design. Timed pregnant Sprague Dawley rats were fed control or TCC supplemented chow (0.2% or 0.5% (w/w)) ad lib from gestational day (GD) 5 until weaning/post natal day (PND) 21.  Maternal body weight (BW) during gestation was monitored.  On PND 0, litters were culled to 6 females per dam followed by cross-fostering of pups between the three dam groups. Pup BW and survival rate were recorded daily.  On PND 21, dams were necropsied and systemic and sex organs were weighed.  Breast tissue was removed and processed for histological evaluation. Serum was collected for TCC and hormone analysis.  No difference in number of implantation or total live births at PND 0 was found.  After cross-fostering, a reduced survival rate was shown among neonates suckling from TCC exposed dams, while 100% of pups suckling from control dams, including those born to treated dams but fostered by control dams, survived to PND 21.  Length of survival among pups nursed by treated dams was dose dependent, as no pups suckling from 0.5% (w/w) TCC treated dams survived at PND 6 and 57% of pups suckling from 0.2% (w/w) TCC treated dams survived at PND 9. While initial group mean BW did not differ at PND 0, by PND 3, pups nursed by control dams were significantly heavier compared to those nursed by either treated group.  Only 13% of pups raised by 0.2% (w/w) TCC treated dams survived after weaning with an average BW of 49% of the BW of pups suckling from control dams at PND 21.  Histological evaluation of breast tissue collected from treated dams revealed evidence of involution, with inflammatory cell infiltration or inflammation compared to control lactating tissue. Additionally, circulating T3 levels were significantly elevated among 0.5% (w/w) treated dams at weaning compared to controls, indicating TCC exposure might influence maternal thyroid hormone homeostasis in vivo.  Our data suggests the critical exposure window affecting neonate survival is related to lactation because all neonates raised by control dams survived regardless of in utero exposure status. This information provides supporting evidence for the potential adverse effects of TCC exposure during early life.

Nothing to Disclose: RCK, LH, KF, LZ, PH, NAG, BLL, KB, JC

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: Supported by National Institute of Environmental Health Sciences 1R21ES017475-01A1.