Fig. 1

A set of microphotographs and a graph documenting zebrafish hair cells rescued phenotype in Xanthohumol (XN) treated zebrafish larvae groups after the damage resulting from 40 min 10 μM CuSO4 exposure in 3 dpf Tg(brn3c:GFP) larvae. Images from a to e present L4 neuromast. (a) Control neuromast exhibited normal neuromast rosette with pear shaped cells (yellow arrows). (b) 40 min 10 μM CuSO4 exposure evoked severe hair cell rosette disintegration resulting in the ruptured cell membrane and released cell content (cloud-like appearance) (white arrowheads). (c) In 0.1 μM XN co-treated group the ruptured cell membrane was still present (white arrowheads), however round (white arrow) and pear shaped (yellow arrow) cells were also distinguishable. (d) 0.3 μM XN co-treatment and (e) 0.5 μM XN co-treatment significantly rescued severe phenotype resulting in a greater number of round (white arrow) and pear shaped (yellow arrow) cells. Red arrowheads points to areas within the cells with greater expression of GFP signal, suggesting chromatin condensation (c, d, e). Images from f to i present L4 and L5 neuromasts after an additional 1 h post CuSO4 exposure (red arrows). Images with 1 and 2 numbers correspond to main images and show single neuromasts under 2× magnification. Images with prims show the same elements on black background for better visualization. (f set) CuSO4 exposure resulted in almost no signal derived from persisting hair cells. (g, h, I sets) In XN treated groups the green GFP signal was detectable and the cells become shrunken and round (white arrows). The visualization was accomplished using a Zeiss LSM-700 confocal microscope (10× and 20× objectives). (j) the graph presenting the number of persisting hair cells after XN co-incubation (expressed as the area covered by hair cells) which increased in a dose-dependent manner (one-way ANOVA, GraphPad Prism 5, *** p < 0.001, ** p < 0.01). Scale bar = 10 μm (a-e and images with 1 and 2 numbers and prims). Scale bar = 150 μm (f - i).