US EPA

1248012 

Journal Article 

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

Bonventre, JA; White, LA; Cooper, KR 

2012 

Yes 

Aquatic Toxicology
ISSN: 0166-445X
EISSN: 1879-1514 

Elsevier BV 

120-121 

45-53 

English 

22609741 

10.1016/j.aquatox.2012.04.008 

WOS:000306615500006 

Gasoline additives ethyl tert butyl ether (ETBE) and tertiary amyl methyl ether (TAME) are used world wide, but the consequence of developmental exposure to these hydrophilic chemicals is unknown for aquatic vertebrates. The effect of ETBE and TAME on zebrafish embryos was determined following OECD 212 guidelines, and their toxicity was compared to structurally related methyl tert-butyl ether (MTBE), which is known to target developing vasculature. LC50s for ETBE and TAME were 14mM [95% CI=10-20] and 10mM [CI=8-12.5], respectively. Both chemicals caused dose dependent developmental lesions (0.625-10mM), which included pericardial edema, abnormal vascular development, whole body edema, and craniofacial abnormalities. The lesions were suggestive of a dysregulation of WNT ligands and matrix metalloproteinase (MMP) protein families based on their roles in development. Exposure to 5mM ETBE significantly (p≤0.05) decreased relative mRNA transcript levels of mmp-9 and wnt3a, while 2.5 and 5mM TAME significantly decreased wnt3a, and wnt8a. TAME also significantly decreased mmp-2 and -9 mRNA levels at 5mM. ETBE and TAME were less effective in altering the expression of vascular endothelial growth factor-a and -c, which were the only genes tested that were significantly decreased by MTBE. This is the first study to characterize the aquatic developmental toxicity following embryonic exposure to ETBE and TAME. Unlike MTBE, which specifically targets angiogenesis, ETBE and TAME disrupt multiple organ systems and significantly alter the mRNA transcript levels of genes required for general development. 

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