The alcohol‐sensitive period during early octavolateral organ development in zebrafish (Danio rerio). Issue 5 (20th January 2017)

• Record Type: Journal Article
• Authors: Zamora, Lilliann Y.; Miguel, Kayla C.; Lu, Zhongmin
• Is Part Of: Journal of neuroscience research. Volume 95:Issue 5(2017)
• Page Start: 1194
• Page End: 1203
• Publication Date: 2017-01-20
• Subjects: hair cell -- hearing -- lateral line neuromast -- otic vesicle -- otolith; Neurobiology -- Periodicals; 612
• DOI: 10.1002/jnr.24017
• Languages: English
• ISSNs: 0360-4012

Abstract

Abstract : Fetal alcohol exposure can cause Fetal Alcohol Spectrum Disorders (FASD), completely preventable developmental disabilities characterized by permanent birth defects. However, specific gestational timing when developing organs are most sensitive to alcohol exposure is unclear. In this study, we examined the temporal effects of embryonic alcohol exposure on octavolateral organs in zebrafish ( Danio rerio ), including inner ears and lateral line neuromasts that function in hearing, balance, and hydrodynamic detection, respectively. To determine an alcohol‐sensitive period in the first 24 hours post fertilization (hpf), Et(krt4:EGFP) sqet4 zebrafish that express green fluorescent protein in sensory hair cells were treated in 2% alcohol for 2, 3, and 5‐hours. Octavolateral organs of control and alcohol‐exposed larvae were examined at 3, 5, and 7 days post fertilization (dpf). Using confocal and light microscopy, we found that alcohol‐exposed larvae had significantly smaller otic vesicles and saccular otoliths than control larvae at 3 dpf. Only alcohol‐exposed larvae from 12‐17 hpf had smaller otic vesicles at 5 dpf, smaller saccular otoliths at 7 dpf and fewer saccular hair cells, neuromasts and hair cells per neuromast at 3 dpf. In addition, auditory function was assessed by microphonic potential recordings from inner ear hair cells in response to 200‐Hz stimulation. Hearing sensitivity was reduced for alcohol‐exposed larvae from 7‐12 and 12‐17 hpf. Our results show that 12‐17 hpf is an alcohol‐sensitive time window when morphology and function of zebrafish octavolateral organs are most vulnerable to alcohol exposure. This study implies that embryonic alcohol exposure timing during early development can influence severity of hearing deficits. © 2017 Wiley Periodicals, Inc. Abstract : Results from this study indicate an alcohol‐sensitive period during embryonic development that can cause morphological and functional defects of hearing organs in zebrafish. Specific timing of human fetal alcohol exposure may also lead to decreased hearing capacity, a known characteristic of FASD.