You are here:
BRAIN AND BLOOD TIN LEVELS IN A DEVELOPMENTAL NEUROTOXICITY STUDY OF DIBUTYLTIN.
Citation:
MOSER, V. C., K. EHMAN, P. PHILLIPS, AND K. MCDANIEL. BRAIN AND BLOOD TIN LEVELS IN A DEVELOPMENTAL NEUROTOXICITY STUDY OF DIBUTYLTIN. Presented at Society of Toxicology, Charlotte, NC, March 25 - 29, 2007.
Description:
Dibutyltin (DBT), a widely used plastic stabilizer, is detected in the environment and human tissues. While teratological and developmental effects are known, we could find no published report of DBT effects on the developing nervous system. As part of a developmental neurotoxicity study of DBT, we periodically collected samples to determine the distribution of tin (Sn). Pregnant Sprague-Dawley rats were exposed to 0, 10, or 25 ppm DBT in drinking water from gestational day 6 to weaning. Beginning on postnatal day (PND) 3, half of the litters were directly dosed (DD group) every 2 to 3 days via gavage with 0, 1, or 2.5 mg/kg DBT such that the dose level matched the water concentration (i.e., litters with 25 ppm DBT in the water received 2.5 mg/kg). For Sn analysis, brain and blood samples were collected from culled pups on PND2 (sex combined), from pups (both sexes) as well as the dams at weaning (PND21), and from adult offspring (both sexes) at PND93. Total Sn was quantified using ICP-MS. At all ages, brain Sn levels were higher than in blood. At culling and in the DD pups at weaning, Sn levels in both tissues were linearly related to dose. Weanling pups without direct dosing showed lower levels than either the culled pups or the dams, indicating that lactational exposure is minimal or negligible even while maternal exposure is ongoing. In the adults, there was still Sn present in the brains of DD rats, but only females had measurable blood Sn levels, perhaps indicating more rapid clearance from blood in the males. The remaining adults had very low, but still measurable, Sn in the brain but not at all in blood. Thus, during exposure to DBT in drinking water, Sn is placentally, but not lactationally, transferred to the offspring. Our data suggest that Sn is concentrated in the brain compared to the blood, and its elimination with cessation of exposure is protracted, on the order of months. This exposure to the developing brain suggests the potential for neurotoxic effects.
This is an abstract of a proposed presentation and does not necessarily reflect US EPA policy.