Prenatal developmental toxicity study of ethyltertiary-butyl ether in rabbits

Abstract

Ethyl tertiary-butyl ether (ETBE) is commonly used as an oxygenated gasoline additive. In this study, the prenatal developmental toxicity of ETBE was determined in rabbits. New Zealand white rabbits were given ETBE by gavage at 100, 300, or 1,000 mg/kg/day on gestational days (GDs) 6-27, and the pregnancy outcome was determined on GD 28. Neither death nor abortion occurred in the pregnant rabbits at any dose. Slightly and significantly suppressed maternal body-weight gain and transiently decreased maternal food consumption were found at 1,000 mg/kg/day during the administration period. At this dose, no changes in clinical or macroscopic finding were noted in dams. No treatment-related changes were observed in any dam treated at 300 mg/kg/day or less. There was no significant effect of ETBE on the numbers of corpora lutea, implantations, live fetuses, resorptions and dead fetuses, incidences of pre- and postimplantation loss, viability of fetuses, fetal body weight, sex ratio of fetuses, or weights of gravid uteri. No significant difference was detected in the incidences of fetuses with malformations or variations between the ETBE-treated and control groups. Also, no adverse effects on the progress of ossification were noted in fetuses of dams given ETBE. Based on these findings, it is concluded that the no observed adverse effect levels of ETBE were 300 mg/kg/day for dams and 1,000 mg/kg/day for fetuses in rabbits.

Craniofacial abnormalities and altered wnt and mmp mRNA expression in zebrafish embryos exposed to gasoline oxygenates ETBE and TAME

“…It is possible that higher concentrations of MTBE could result in effects on craniofacial development, although based on the morphological observations reported in Bonventre et al (2011), MTBE did not induce cranial structures deformities in treatments as high as 25 mM MTBE (Bonventre et al, 2011). Similarly, craniofacial abnormalities, including cleft palate, were previously reported for mammalian developmental models with MTBE and TAME exposure, but not with ETBE (Bevan et al, 1997, Welsh et al, 2003; Asano et al., 2011). The craniofacial structures measured in our study are similar to cleft palate formation in mammals in that they involve comparable molecular mechanisms, specifically the involvement of both WNTs and MMPs.…”

“…Developmental inhalation studies for ETBE have not been published. However, rat and rabbit developmental studies report no adverse effects to fetuses exposed prenatally up to 1,000 mg/kg/day (9.8 moles/kg/day) ETBE (Asano et al, 2011, reviewed in de Peyster, 2010). TAME gestational inhalation studies reported NOAELs to be 1500 ppm (14.7 moles/m 3 air) for rat fetuses and 250 ppm (2.5 moles/m 3 air) for mice fetuses (Welsh et al, 2003).…”

Identification and Validation of FGF10, SP-B and FOXM1 Genes for Regulating Histogenesis of the Fetal New Zealand White Rabbit (Oryctolagus cuniculus) Lungs

“…Rabbit are the most frequently used animals in a variety of biomedical research fields. The latter fields include: neuroscience, oncology, cardiovascular, dermatology, reproduction and embryonic development [1][2][3]. Embryonic, fetal, and postnatal developmental phases of lungs are the foremost phases.…”

Expression Pattern of DMRT1 and STRA8 Genes During Postnatal Development of Rabbit Testes

“…The rabbit is an excellent model used in a variety of biomedical research fields including neuroscience, oncology, embryonic development, cardiovascular studies, dermatology, and reproduction (Ewuola & Equnike, 2010; Asano et al, 2011 andGuo et al, 2012). Rabbit is an attractive species for making gonad studies due to easily identification of the morphological changes of the seminiferous epithelium cycle (Ewuola and Equnike, 2010).…”