Ethanol exposure significantly reduced the number of proliferating cells compared to untreated controls in O2 neuromasts of Brn3c GFP-larvae.

<p>(A) Under untreated control conditions, proliferating cell nuclear antigen (PCNA)-labeled cells (arrowhead) are primarily non-sensory supporting cells and mantle cells in the neuromast (area demarked by white dotted line). Fewer PCNA-labeled cells result from ethanol treatment at (B) 1% and (C) 1.5% by volume. (D) The mean number of PCNA-labeled cells decreases during maturation and according dose of ethanol. (E) In a separate experiment, bromodeoxyuridine was added to the embryo medium during the last 24 hours of treatment, fixed, processed for BrdU immunohistochemistry, and BrdU-labeled cells were counted. Significantly fewer BrdU-labeled cells were observed in ethanol-treated animals when compared to untreated controls. Results are the mean values ± SD. n = 10-21 neuromasts for each treatment group. **p<0.01.