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Determination of the No‐Effect Dose of Bis(tri‐n‐butyltin)oxide (TBTO) for Maternal Toxicity and Teratogenicity in Mice
Author(s) -
FAQI Ali S.,
SCHWEINFURTH Hermann,
CHAHOUD Ibrahim
Publication year - 1997
Publication title -
congenital anomalies
Language(s) - English
Resource type - Journals
eISSN - 1741-4520
pISSN - 0914-3505
DOI - 10.1111/j.1741-4520.1997.tb00550.x
Subject(s) - fetus , toxicity , developmental toxicity , gestation , teratology , pregnancy , medicine , no observed adverse effect level , physiology , toxicology , biology , genetics
Tri‐n‐butyltin oxide (TBTO) is a biocide used in wood preservatives and ship paint system. Available literature data on maternal toxicity and embryotoxicity of TBTO in mice appears to be contradictory. The purpose of the study was to determine a no‐observed‐adverse‐effect‐level (NOAEL) for these parameters and to reevaluate terato‐genic potency of the substance. Pregnant mice were treated orally by gavage daily with 0.5, 1.5, 4.5, 13.5, or 27 mg TBTO/kg body weight (b.w.) on days 6–17 of gestation. The control group received 5 ml/kg b.w. peanut oil daily during the entire treatment period. Evidence of maternal toxicity was only observed at the dose level of 27 mg TBTO/kg. In this group 3 of 40 animals died during the treatment period. The number of implantation sites, number of viable fetuses, fetal sex ratio, number of dead fetuses as well as the number of resorptions showed no dose‐related effects. The fetuses of dams exposed to the highest dose (27 mg TBTO/kg b.w.) revealed a high incidence of cleft palate (11.4%) when compared to the fetuses of the vehicle control group (0.8%). Additionally at this dose level 2 fetuses (1.2%) exhibited a bent radius; 8 fetuses (5%) were observed with a short mandible, and 5 fetuses (3%) showed a fusion of occipital bones with their basal parts. No signs of maternal and prenatal toxicity could be detected in mice under the experimental conditions chosen up to the dose of 13.5 mg TBTO/kg b.w. which represents a no‐observed‐adverse‐effect level (NOAEL).