Fig. 3

Nicotine-induced hair cell toxicity at 120 hours post-fertilization (hpf). The total number of hair cells was measured in four neuromasts (supraorbital [SO1 and SO2], otic [O1], and occipital [OC1]; total n=150). (A) The number of hair cells decreased in nicotine-exposed groups as shown by fluorescent microscopy (OC1, ×40). Scale bar=10 μm (×10). (B) Animals in the normal control group had an average of 49.8 hair cells. Nicotine exposure significantly decreased the number of total hair cells of the four neuromasts compared with that of the normal control, (P<0.001, one-way analysis of variance). At a concentration of 40 μM nicotine almost all the fish were dead, therefore statistical analysis was unavailable. All data were evaluated using transgenic (brn3c:EGFP) zebrafish at 120 hpf. Only statistically significant pair-wise comparisons in posthoc analysis are shown. *Statistically significant (P<0.05).