Figure 7. SEM stereoimaging validation of hair bundle heights measurements.

(a) Representative micrographs of E6.5 BPs that were cultured for 7 days in control medium or media supplemented with RA or citral. HCs were viewed from behind the longest stereocilia and stereopair images were taken from four neighbouring fields at a distance of ~18% of the total length of the BP away from the proximal and distal ends (n_BPs = 4 for each treatment). Micrographs were blinded and hair bundle heights were then measured from stereopair images. (b) Quantifications of the stereocilia lengths that were measured from stereopair SEM images taken at 15,000 X. Proximal HCs were taller in the RA-treated BPs compared with control BPs: 3.37±0.22 mm versus 1.46±0.20 mm, respectively. Further, distal HCs were shorter in the BPs treated with citral compared with controls: 1.21±0.25 mm versus 1.93±0.19 mm, respectively. *P<0.05; one-way ANOVA with Newman–Keuls post-test. Graph shows the mean hair bundle height measured in the proximal and distal regions ±s.e.m. Scale bars, 1 µm.