Ethanol exposure alters zebrafish development: a novel model of fetal alcohol syndrome.

Prenatal exposure to alcohol has been shown to produce the overt physical and behavioral symptoms known as fetal alcohol syndrome (FAS) in humans. Also, it is believed that low concentrations and/or short durations of alcohol exposure can produce more subtle effects. The purpose of this study was to investigate the effects of embryonic ethanol exposure on the zebrafish (Danio rerio) in order to determine whether this species is a viable animal model for studying FAS. Fertilized embryos were reared in varying concentrations of ethanol (1.5% and 2.9%) and exposure times (e.g., 0-8, 6-24, 12-24, and 48-72 h postfertilization; hpf); anatomical measures including eye diameter and heart rate were compared across groups. Results found that at the highest concentration of ethanol (2.9%), there were more abnormal physical distortions and significantly higher mortality rates than any other group. Embryos exposed to ethanol for a shorter duration period (0-8 hpf) at a concentration of 1.5% exhibited more subtle effects such as significantly smaller eye diameter and lower heart rate than controls. These results indicate that embryonic alcohol exposure affects external and internal physical development and that the severity of these effects is a function of both the amount of ethanol and the timing of ethanol exposure. Thus, the zebrafish represents a useful model for examining basic questions about the effects of embryonic exposure to ethanol on development.