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EVALUATION OF PERFLUOROOCTANE SULFONATE IN THE RAT BRAIN
Citation:
LAU, C. S., J. R. THIBODEAUX, K. DAS, D. EHRESMAN, S. TANAKA, J. FROEHLICH, AND J. BUTENHOFF. EVALUATION OF PERFLUOROOCTANE SULFONATE IN THE RAT BRAIN. Presented at Society of Toxicology, San Diego, CA, March 05 - 09, 2006.
Description:
Perfluorooctane Sulfonate (PFOS) is an environmentally persistent chemical that has been detected in humans and wildlife. PFOS is primarily distributed in liver and blood. The current study evaluated the level of PFOS in the adult and neonatal rat brain and determined whether there was a differential distribution among brain regions. Sprague-Dawley rats (60-70 day old) were given 3 mg/kg PFOS/K+ by oral gavage daily for 14 days and sacrificed 24 h after the last treatment. A blood sample was obtained from the tail vein prior to sacrifice, and the brain was perfused with isotonic saline. Five brain regions: cerebral cortex, hippocampus, cerebellum, hypothalamus and brainstem, were dissected immediately and stored frozen at -80oC until analysis. For the developmental study, timed-pregnant rats were given PFOS (3 mg/kg) daily from gestational day 2 to 21 and allowed to deliver litters. Pups were sacrificed on postnatal day 7, and their brains were perfused and dissected similarly to the adults. Trunk blood was obtained from littermates. Extraction of brain homogenate employed a base digestion followed by a solid phase extraction at an acidic pH for optimal recovery. PFOS was determined by HPLC-MS-MS. Mean serum PFOS was 123 ?g/ml for the adults and 52 ?g/ml for the pups. Mean concentrations of PFOS among adult brain regions ranged from 5-8 ?g/g, or 4.5-6.6% of the serum level. In contrast, PFOS in neonatal brain ranged from 16 – 29 ?g/g, or 29-55% of serum level. These data indicated a limited presence of PFOS in the adult rat brain after subchronic exposure, with no differential distribution among regions. However, compared to the adults, substantially higher concentrations of PFOS were detected in the neonatal brain, likely due to incomplete formation of the blood-brain barrier at that developmental stage. This abstract does not necessarily reflect EPA policy.